WO2023076477A2 - Orally disintegrating tablet for epinephrine prodrug formulations - Google Patents

Abstract

The disclosure provides orally disintegrating epinephrine prodrug tablet (ODT) that includes epinephrine prodrug, a pharmaceutically acceptable salt thereof, a binder, a matrix former, and a taste masking agent. The ODT of the disclosure rapidly provide epinephrine to a patient when administered. The disclosure also provides a method of treating a patient who has a condition responsive to epinephrine such as a cardiac event, asthma, croup, cancer, a microbial infection, Addison's disease, or an allergic reaction, particularly anaphylaxis by administering an orally disintegrating epinephrine prodrug tablet to the patient.

Description

ORALLY DISINTEGRATING TABLET FOR EPINEPHRINE PRODRUG FORMULATIONS

CROSS REFERENCE TO RELATED APPLICATION

[0001] This application claims priority to U.S. provisional appl. no. 63/272,520, filed October 27, 2021, which is hereby incorporated by reference in its entirety.

FIELD OF THE DISCLOSURE

[0002] This disclosure provides epinephrine prodrug orally disintegrating tablet formulations. The disclosure also provides a method of treating a patient who has a condition responsive to epinephrine such as a cardiac event, asthma, croup, cancer, a microbial infection, Addison's disease, or an allergic reaction, particularly anaphylaxis by administering an orally disintegrating dipivefrin tablet formulations to the patient.

BACKGROUND

[0003] Epinephrine is used to treat a number of conditions including anaphylaxis, cardiac arrest, and superficial bleeding, asthma and croup. Injectable epinephrine has also been shown to be efficacious for preventing and treating cancer. U.S. Patent No. 5,925,682 discloses that injecting a mammal with an effective amount of epinephrine results in the significant reduction of tumorous growth. Epinephrine may also be efficacious in treating microbial infections. Epinephrine, delivered via intramuscular or subcutaneous injection, is a drag of choice for emergency treatment of anaphylaxis. It is commercially available in injectable form delivered by autoinjectors or pre-filled syringes. In the US, epinephrine injection comes in 0.5 mg, 0.3mg, 0.15 mg and 0.1 mg dosage strengths for emergency treatment of anaphylaxis. US patent US 10,039,710 B2 discloses epinephrine spray formulations for anaphylaxis that can be administered via the sublingual or intranasal route. There remains a need for effective, economical, and easy to use formulations that can quickly deliver epinephrine into a patient's bloodstream.

[0004] An epinephrine prodrag can provide an alternative for the delivery of epinephrine. US patent application Pub No US 2019 / 0076378 Al discloses using epinephrine prodrug dipivefrin, including L-dipivefrin, for systemic delivery of epinephrine. US patent application Pub No US 2020/0276114 Al discloses dipivefrin, including L- dipivefrin hydrochloride, orally dissolving tablet formulations A number of other epinephrine prodrugs are known in the art.. A prodrug can present improved hydrophobicity, better permeation, dose reduction, reduced side effects, enhanced speed of absorption and better metabolic stability. It can also provide alternative compositions with unique stability profiles. Other prodrugs could have similar stability and/or be designed based on the desired stability profile exhibited with certain additives.

[0005] The current disclosure provides an effective, convenient, an easy to use formulation capable of quickly delivering a therapeutic level of epinephrine to a patient's bloodstream and provides additional advantages.

SUMMARY

[0006] This disclosure is directed to an epinephrine prodrug orally disintegrating tablet (ODT), comprising an epinephrine prodrug, or its pharmaceutically acceptable salt, a binder, a disintegrator and/or matrix former, and a taste masking agent and optionally a permeation enhancer. The epinephrine prodrug disclosed in the instant application is not dipivefrin, L-dipivefrin or its pharmaceutically acceptable salts. The epinephrine prodrug is a compound of the formula

or a pharmaceutically acceptable salt thereof wherein

R¹, R², R³, and R⁴ are independently chosen from H, C₁-C₁₂alkylcarbonyl, mono or di-C₁-C₁₂alkylaminocarbonyl, C₁-C₁₂alkoxycarbonyl, (C₃-C₆cycloalkyl)C₀-C₄alkylcarbonyl, phenylC₀-C₄alkylcarbonyl, (C₀-C₁₂alkyl)sulfate, and (C₀-C₁₂alkyl)phosphate;

Where each alkyl or alkoxy in the definition of R³ optionally contains one or more double or triple bonds, has one or more CH? groups replaced by O, S, NH, or NR⁵ where R⁵ is C1-C6alkyl, and is optionally substituted with one or more substituents independently chosen from halogen, hydroxyl, nitro, amino, oxo, or cyano;

Where the R¹ alkyl or alkoxy may be joined to the R² alkyl or alkoxy to form a 5 to 7-membered ring or the R³ alkyl or alkoxy may be joined to the R⁴ alkyl or alkoxy to form a 5- to 7-membered ring; and

Where not all of R¹, R², R³, and R⁴ are H, and dipi vefrin (R¹ and R² = pivaloyl group, R³ = R⁴ - H) is excluded. [0007] In certain embodiments the ODT comprises about 0.01 mg, to about 60 mg the epinephrine prodrug or 0.5mg, 1.0 mg, 2.5 mg, 5 mg, 10 mg, or 20 mg epinephrine prodrug. The epinephrine prodrug ODT of the disclosure can have a total tablet weight of less than 100 mg. The epinephrine prodrug ODT of the disclosure can comprise 10 to 70% binder (wt%), 5 to 50% matrix former and/ or disintegrat'd (wt%), and 1 to 20%' taste masking agent (wt%). The binder can comprise gelatin and/ or povidone. The matrix former can be glycine or mannitol. The taste masking agent can include citric acid and/or a sweetener such as sucralose and sodium saccharin. The epinephrine prodrug ODT composition can optionally contain a chelating agent. The epinephrine prodrug ODT composition can optionally contain an antioxidant. The epinephrine prodrug ODT composition can optionally contain a permeation enhancer. The epinephrine prodrug ODT composition can optionally contain a flavoring agent. The epinephrine prodrug ODT composition can optionally contain a colorant. The epinephrine prodrug ODT composition of the present disclosure can optionally contain a pH modifier.

[0008] The epinephrine prodrug ODT of this disclosure is suitable for treating conditions in a subject such as anaphylaxis in which epinephrine is urgently needed in the subject's systemic circulation. As such the disclosure include epinephrine prodrug ODTs capable of providing an epinephrine T_max of less than 60 min, less than 45 minutes from administration to the subject and an epinephrine plasma C_max of 0.1 to 50 ng/mL when administered to a subject.

[0009] In certain embodiments the epinephrine prodrug ODT contains not more than 10 mg of epinephrine prodrug hydrochloride and provides a plasma level of epinephrine at 20 minutes after administration that is equal or greater than a plasma level of epinephrine provided by a US FDA-approved 0.3 mg injectable epinephrine dosage form. The US FDA- approved injectable epinephrine dosage form can be a 0.5mg, 0.3 mg, 0.15 mg, or 0.1 mg epinephrine dosage form for intramuscular administration. The US FDA-approved injectable epinephrine dosage form can be a 0.5 mg, 0.3 mg, 0.15 mg, or 0.1 mg epinephrine dosage form for subcutaneous administration.

[0010] The disclosure includes a method of treating a subject suffering from a condition responsive to epinephrine by administering a epinephrine prodrug ODT of the disclosure. The condition responsive to epinephrine can be a breathing difficulty, such as a breathing difficulty is associated with anaphylaxis, asthma, bronchitis, emphysema, croup, or a respiratory infection. In certain embodiments the condition responsive to epinephrine is anaphylaxis. [0011] The disclosure includes a method of reducing the severity of an allergic reaction or anaphylaxis or inhibiting the onset of an allergic reaction or anaphy laxis in a subject, comprising administering a epinephrine prodrug ODT of the disclosure to the subject following exposure of the subject to an allergen. The epinephrine prodrug ODT of the disclosure can be the only pharmaceutical agent administered to a subject or can be administered together with another pharmaceutical agent such as an antihistamine, for example diphenhydramine.

[0012] The disclosure includes a method for treating a condition responsive to epinephrine in a subject, in which tire subject has a deficiency of epinephrine. The deficiency can be short term or chronic. Such conditions include Addison's disease, adrenal hyperplasia, hypoglycemia, or chronic active hepatitis.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] FIGURE 1. Mean plasma epinephrine concentration vs time profiles after single oral dose of epinephrine prodrug (dipivefrin) HC1 orally disintegrating tablet 5mg and single standard epinephrine IM injection 0.3 mg in beagle dogs (cross over design, N=3).

[0014] FIGURE 2. Mean plasma epinephrine concentration vs time profiles after single oral dose of epinephrine prodrug (dipivefrin) HC1 orally disintegrating tablet 5 mg and

63.5 mg in beagle dogs (cross over design, N=3).

[0015] FIGURE 3. Mean plasma epinephrine concentration vs time profiles after single oral dose of epinephrine prodrug (dipivefrin) HC1 orally disintegrating tablet 1.0 mg,

2.5 mg and single standard epinephrine IM injection 0.3 mg in beagle dogs (cross over design, N=6).

DETAILED DESCRIPTION

TERMINOLOGY

[0016] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms, including "at least one," unless the content clearly indicates otherwise. "Or" means "and/or." As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items. It will be further understood that the terms "comprises" and/or "comprising," or "includes" and/or "including" when used in this specification, specify the presence of stated features, regions, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, regions, integers, steps, operations, elements, components, and/or groups thereof.

[0017] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0018] As used herein, the term "epinephrine prodrug orally disintegrating tablet" or "epinephrine prodrug orally dissolving tablet" or "epinephrine prodrug ODT' refers to an orally disintegrating tablet comprising epinephrine prodrug (freebase), or a pharmaceutically acceptable salt, solvate, or polymorph of dipivefrin. A preferred epinephrine prodrug ODT comprises epinephrine prodrug hydrochloride or L-epinephrine prodrug hydrochloride.

[0019] The structures of epinephrine prodrug and L-epinephrine prodrug are as follows:

Epinephrine Prodrug L-Epinephrine Prodrug

[0020] Each of R¹-R⁴ carries the definitions set forth above. Alternatively R¹, R², R³, and R⁴ are independently chosen from H, C₁-C₆alkylcarbonyl, mono or di-C₁- C₁₆alkylaminocarbonyl, C₁-C₆alkoxycarbonyl, phenylC₀-C₂alkylcarbonyl, (C₀- C₆alkyl)sulfate, and (C₀-C₆alkyl) phosphate;

[0021] Where each alkyl or alkoxy in the definition of R³ optionally contains one or more double or triple bonds, has one or more CH₂ groups replaced by O, S, NH, or NR³ where R⁵ is C₁-C₆alkyl, and is optionally substituted with one or more substituents independently chosen from halogen, hydroxyl, nitro, amino, oxo or cyano. .

[0022] In certain embodiments R¹, R², R³, and R⁴ are independently selected from any of H, CH₃C(O)-, CH₃CH₂C(O)-, CH₃CH₂OC(O)-, CH₃(CH₂)₂C(O)-, CH₃(CH₂)₃C(O)-, CH₃(CH₂)₅C(O)-, (CH₃)₂CHC(O)-, CH₃(CH₂)₃OC(O)-, (CH₃)CC( O). (CH₃CH₂)(CH₃)₂CC(O)-, (CH₃)NC(O)-, CH₃(CH₂)₄OC(O)- phenylC(O)- benzylC(O)- cyclopropylC(O)- and cyclopropylCIRClO)-. The caveats that not all for R^l-R^; are H and dipivefrin is excluded apply. C(O)- is a carbonyl and the point of attachment is on the carbon atom.

[0023] In certain embodiments one or more of the following conditions are met:

(1) R¹ and R² are the same.

(ii) R ³ and R² are both not hydrogen.

(ii i) R³ and R⁴ are both hydrogen.

(iv) R¹, R², and R³ are the same and are not hydrogen, R⁴ is hydrogen.

(v) R^; and R² are hydrogen and R³ is not hydrogen.

[0024] Exemplary epinephrine prodrugs disclosed in this application are shown below:

[0025] The epinephrine prodrugs disclosed in this application can be prepared using methods readily available in the literature.

[0026] As used herein, the term "pharmaceutically acceptable salt" is a salt formed from, for example, an acid and a basic group of an epinephrine prodrug composition. Illustrative salts include, but are not limited to, sulfate, citrate, acetate, oxalate, chloride, acid chloride, bromide, iodide, nitrate, phosphate, acid phosphate, isonicotinate, lactate, salicylate, acid citrate, tartrate, oleate, tannnate, pantothenate, bitartrate, ascorbate, succinate, maleate, besylate, gentisinante, fumarate, gluconate, glucaronate, saccharate, formate, benzoate, glutamate, methanesulfonate, ethanesulfonate, benzenesulfonate, p-toluenesulfonate, and pamoate (e.g., 1,1-methylene-bis~(2"hydroxy"3-naphthoate)) salts. In an embodiment, the salt of epinephrine prodrugis a hydrochloride salt. Unless clearly contraindicated by the context, "dipivefrin" includes the pharmaceutically acceptable salts of dipivefrin.

[0027] The term "pharmaceutically acceptable salt" also refers to a salt prepared from a composition having an acidic functional group, such as a carboxylic acid functional group, and a pharmaceutically acceptable inorganic or organic base and also to a salt prepared from a composition having a basic functional group, such as an amino functional group, and a pharmaceutically acceptable inorganic or organic acid.

[0028] A "pharmaceutical agent" means a compound (including for example, an epinephrine prodrug or epinephrine), element, or mixture that when administered to a subject, alone or in combination with another compound, element, or mixture, confers, directly or indirectly , a physiological effect on the subject. The indirect physiological effect may occur via a metabolite or other indirect mechanism.

[0029] The terms "administer", "administering", "administered" or "administration" refer to any manner of providing a pharmaceutical agent (such as epinephri ne prodrug or a pharmaceutically acceptable salt thereof) to a subject or patient. Routes of administration can be accomplished through any means known by those skilled in the art. Such means include oral, buccal, intravenous, subcutaneous, intramuscular, transdermal, and inhalation, sublingual, intranasal. Oral administration is a preferred route of epinephrine prodrug administration.

[0030] The terms "taken orally" and "oral administration" refer to a manner of providing a pharmaceutical agent to a subject or patient by the mouth through the gastrointestinal tract (digestive tract, digestional tract, GI tract, GIT, gut, or alimentary canal) and/or through the oral mucosa and are used interchangeably . The gastrointestinal tract is tut organ system within humans and other animals which takes in food, digests it to extract and absorb energy and nutrients, and expels the remaining waste as feces. The mouth, esophagus, stomach and intestines are part of the gastrointestinal tract.

[0031] A "dosage form" means a unit of administration of a pharmaceutical agent. In this disclosure the dosage forms are orally disintegrating tablets. [0032] An "orally disintegrating (or dissolving) tablet" is a solid dosage form that disintegrates or dissolves rapidly, usually within a matter of seconds, when placed in the mouth. Orally disintegrating dosage forms are designed to disintegrate or dissolve rapidly on contact with saliva, thus eliminating the need for chewing, swallowing, or taking the solid dosage with water. An orally disintegrating dosage can promote pregastric absorption of the active ingredients through buccal, sublingual, oropharyngeal and esophageal membranes. As a result, an orally dissolving dosage can provide faster onset of action and higher bioavailability than a conventional solid dosage form.

[0033] A "pharmaceutically acceptable excipient" means an excipient that is useful in preparing a pharmaceutical composition that is generally safe, non-toxic, and neither biologically nor otherwise undesirable, and includes an excipient that is acceptable for veterinary use as well as human pharmaceutical use. A "pharmaceutically acceptable excipient" as used in the present application includes both one and more than one such excipient.

[0034] A "subject" is a human or non-human mammal, such as a companion animal, e.g. cat or dog. A subject can be a human or non-human patient in need of medical treatment.

[0035] A "therapeutically effective amount" or "effective amount" is that amount of a pharmaceutical agent to achieve a pharmacological effect. The term "therapeutically effective amount" includes, for example, a prophylactically effective amount, that is an amount effective to significantly reduce the probability of occurrence of a disorder in a patient at risk for the disorder. An "effective amount" of epinephrine prodrug is an amount needed to achieve a desired pharmacologic effect or therapeutic improvement without undue adverse side effects. The effective amount of epinephrine prodrug will be selected by those skilled in the art depending on the particular patient and the type of conditions being treated. It is understood that "an effective amount" or "a therapeutically effective amount" can vary from patient to patient, due to variation in general condition of the subject, the condition being treated, the severity of the condition being treated, and the judgment of the prescribing physician. When discussing a method of treating cancerous tissue, an effective amount includes an amount effective to have a statistically significant and favorable effect on the rate of the patient's cancer proliferation over time or on a level of biological marker for the cancer.

[0036] The terms "treating" and "treatment" mean implementation of therapy with the intention of reducing in severity or frequency symptoms, elimination of symptoms or underlying cause, prevention of the occurrence of symptoms or their underlying cause, or the improvement or remediation of damage due to a disorder or disease. In certain embodiments "treatment" includes prophylactic treatment, which includes administering an amount of epinephrine prodrug effective to significantly reduce the proliferation of cancerous tissue, reduce the chance of infection of a patient by a microbial pathogen. In certain embodiments treatment includes inhibiting the onset of anaphylaxis or reducing the severity of allergy symptoms in a subject exposed to an allergen.

ORALLY DISINTEGRATING TABLETS

[0037] An orally disintegrating tablet or orally dissolving tablet (ODT) is a drag dosage form available for a limited range of over-the-counter (OTC) and prescription medications. ODTs differ from traditional tablets in that they are designed to be dissolved on the tongue rather than swallowed whole. The ODT serves as an alternative dosage form for patients who experience dysphagia (difficulty in swallowing) or for patients for whom compliance is a known issue and need an easier to swallow dosage form to ensure that medication is taken. Dysphagia is common among all age groups. It is observed in about 20% of the general population, 33% of hospital patients, and in up to 40%' of patients in long-term care facilities. ODT dosages forms are also an option for pediatric patients too young to swallow pills. ODTs also have a faster onset of action than tablets or capsules due to pregastric absorption (absorption from the mouth, pharynx and esophagus as the saliva passes down into the stomach), and can be conveniently taken without water.

[0038] There has been well documented significant underutilization of epinephrine autoinjectors in the anaphylactic community due to patients' fear of injection, the inconvenience of carrying epinephrine autoinjectors, which must be maintained at a temperature between 20 and 25 °C, and the high cost of epinephrine autoinjectors. ODTs are particularly suitable for delivering epinephrine for emergency treatment of anaphylaxis given their unique advantages as patient-friendly and convenient pharmaceutical dosage forms that can be taken anytime, anywhere and by anyone without water and the need to swallow a whole tablet. It is well known in the art that epinephrine is not absorbed when taken orally, precluding the development of epinephrine ODTs for anaphylaxi s. The inventor has developed new orally disintegrating epinephrine prodrug tablets, suitable for commercial use. The ODTs of this disclosure are stable at temperatures of from less than 0 °C to at least 60 °C and thus provide a significant advantage over epinephrine auto-injectors because they do not need to be stored within a narrow temperature range. Stability of the epinephrine prodrug ODTs of this disclosure can be further enhanced by excluding moisture and oxygen during their manufacture and storage.

[0039] The epinephrine prodrug ODTs of this disclosure contain from about 0.01 to about 60 mg epinephrine prodrug or an epinephrine prodrug salt such as epinephrine prodrug hydrochloride. This disclosure includes ODTs containing 0.1 mg, 0.5 mg, 1.0 mg, 2.0 mg, 3.0 mg, 4.0 mg, 5.0 mg, 7.0 mg. 7.5 mg, 10 mg, 12 mg, 15 mg, or 20 mg or 30 mg epinephrine prodrug or epinephrine prodrug HC1. In any aspect or embodiment described herein, this disclosure includes ODTs comprising 0.01 to about 60 mg, about 0.01 to about 50 mg, about 0.01 to about 40 mg, about 0.01 to about 30 mg, about 0.01 to about 30 mg, about 0.01 to about 15 mg, about 0.01 to about 12 mg, about 0.01 to about 10 mg, about 0.01 to about 7.5 mg, about 0.01 to about 5.0 mg, about 0.01 to about 1.0 mg, 0.1 to about 60 mg, about 0.1 to about 50 mg, about 0.1 to about 40 mg, about 0.1 to about 30 mg, about 0.1 to about 20 mg, about 0.1 to about 15 mg, about 0.1 to about 12 mg, about 0.1 to about 10 mg, about 0.1 to about 7.5 mg, about 0.1 to about 5.0 mg, about 0.1 to about 1.0 mg, 1.0 to about 60 mg, about 1.0 to about 50 mg, about 1.0 to about 40 mg, about 1.0 to about 30 mg, about 1 .0 to about 20 mg, about 1.0 to about 15 mg, about 1.0 to about 12 mg, about 1.0 to about 10 mg, about 1.0 to about 7.5 mg, 5.0 to about 60 mg, about 5.0 to about 50 mg, about 5.0 to about 40 mg, about 5.0 to about 30 mg, about 5.0 to about 20 mg, about 5.0 to about 15 mg, about 5.0 to about 12 mg, 10 to about 60 mg, about 10 to about 50 mg, about 10 to about 40 mg, about 10 to about 30 mg, about 10 to about 20 mg, about 10 to about 15 mg, 15 to about 60 mg, about 15 to about 50 mg, about 15 to about 40 mg, about 15 to about 30 mg, about 15 to about 20 mg, 20 to about 60 mg, about 20 to about 50 mg, about 20 to about 40 mg, about 20 to about 30 mg, 30 to about 60 mg, about 30 to about 50 mg, about 30 to about 40 mg, about 40 to about 60 mg, about 40 to about 50 mg, about 60 to about 50 mg epinephrine prodrug or epinephrine prodrug HC1.

[0040] In any aspect or embodiment described herein, the orally disintegrating epinephrine prodrug tablet of the present disclosure includes one or more excipients. For example, in any aspect or embodiment described herein, the orally disintegrating epinephrine prodrug tablet of the present disclosure includes: (a) one or more fillers, (b) one or more binders, (c) one or more glidants, (d) one or more disintegrants, (e) one or more sweeteners or taste-masking agent, (f) one of more flavors or taste-masking agent, (g) one or more colorants, (h) one or more lubricants, (i) one or more matrix formers, (j ) one or more diluents, or (k) a combination thereof. [0041] The epinephrine prodrug ODTs of this disclosure contain a binder. Nonlimiting examples of suitable binders include water-soluble, alcohol-soluble or acetone/water soluble binders, e.g. gelatin, dextran, alginates, gum Arabic, modified starch, polyvinylpyrrolidone (PVP, also povidone) including PVP K30, Cas. Reg. No. 9003-39-8, corn starch, polyethylene oxide, polyethylene glycol, hydroxypropyl methylcellulose (HPMC), methylcellulose, cellulose derivatives, crystalline cellulose, hyprodroxypropyl methylcellulose, microcrystalline cellulose, methylcellulose, carboxymethylcellulose, sodium carboxymethylcellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, ethylcellulose, microcrystalline dextrose, a sugar, sucrose, D-mannitol, mannitol, glucose, dextrose, molasses, sorbitol, xylitol, lactose, dextrin, sodium alginate, alginic acid and salts thereof, pektines, polyvinyl acetate, povidone, copovidone, crospovidone, polyvinylpyrrolidone, xanthan gum, polyvinyl alcohol, starch, pregelatinized starch, gum tragacanth, a natural or synthetic gum, acacia, tragacanth, ghatti gum, mucilage of isapol husks, amylose, magnesium aluminum silicate, polysaccharide acids, bentonites, polyvinylpyrrolidone/vinyl acetate copolymer, larch arabogalactan, waxes, and hydroxypropylcellulose (HPC) and mixtures thereof. The amount of binder in the epinephrine prodrug ODT ranges from 10% to 70% (wt%), including 10%' to 65%, 10 % to 60%, 10% to 50%, 10% to 40%, 10% to 35%', 20% to 70 %, 20% to 65%, 20 % to 60%, 20% to 50%, 20% to 40%, 20% to 35%, 25% to 70 %, 25% to 65%, 25 % to 60%, 25% to 50%, 25% to 40%, 25% to 35%, 30% to 70 %, 30% to 65%, 30% to 60%, 30% to 50%, 30% to 40%, 30% to 35%, 35% to 70 %, 35% to 65%, 35% to 60%, 35% to 50%, 40% to 70 %, 40% to 65%, 40% to 60%, 40% to 50%, 45% to 70 %, 45% to 60%, 50% to 70 %, and 50% to 60% (wt%).

[0042] The epinephrine prodrug ODTs of this disclosure optionally contain a disintegrant. When the ODTs are prepared by direct compression a distintegrant is typically present. The disintegrant may be any disintegrani suitable for orally disintegrating tablets, for example the disintegrant may be a sugar alcohol such as sorbitol, mannitol, xylitol, isomalt, and hydrogenated starch hydrolysates, or an amino acid such as glycine, the disintegrant may also be crospovidone (crosslinked PVP), sodium starch glycolate, crosslinked sodium carboxy methyl cellulose, low substituted hydroxypropylcellulose, agar-agar, calcium carbonate, potato starch, tapioca starch, alginic acid, certain silicates, sodium carboxymethyl cellulose, starch, pregelatinized starch or mixture thereof. In certain embodiments the disintegrant is mannitol, glycine, or a combination thereof. The amount of disintegrant in the ODTs can be from 1% to 50%' (wt%), including, e.g., 10% to 50%, 10% to 40%, 10% to

30%, 10% to 20%, 15% to 50%, 15% to 40%, 15% to 30%, 15% to 25%, 20% to 50%, 20% to 40%, 20% to 30%, 25% to 50%, 25% to 40%, 25% to 35%, 30% to 50%, 30% to 40%, or 40% to 50%.

[0043] The epinephrine prodrug ODTs of this disclosure optionally contain a matrix former. Epinephrine prodrug ODTs of this disclosure prepared by lyophilization contain a matrix former and optionally contain a disintegrant. The matrix former is preferably a crystalline material that remains crystalline upon lyophilization but dissolves readily in saliva. Matrix formers include gelatins, dextrans, alginates, glycine, crystalline sugars such as mannitol (including D-mannitol), sorbitol, erythritol, and xylitol, microcrystalline cellulose, maltodextran, crystalline cellulose, and mixtures thereof. The amount of matrix former in the ODTs can be from 5% to 50% (wt%), including, e.g., 5% to 50%, 5% to 40%, 5% to 30%, 5% to 20%, 5% to 15%, 10% to 50%, 10% to 40%, 10% to 30%, 10% to 20%, 15% to 50%, 15% to 40%, 15% to 30%, 15% to 25%, 20% to 50%, 20% to 40%, 20% to 30%, 25% to 50%, 25% to 40%, 25%' to 35%, 30% to 50%', 30% to 40%, or 40% to 50%.

[0044] The epinephrine prodrug ODTs of this disclosure include a taste masking agent. Suitable taste masking agents include, but are not limited to, artificial and natural flavorants, citric acid, and sweeteners, including artificial sweeteners, nutritive sweeteners, and sugar alcohols. Examples of sweeteners useful as taste masking agents include saccharin, aspartame, acesulfame K, neotame, sodium saccharin, sucralose, trehalose, tagatose, mannitol, sorbitol, xylitol, erythritol, maltitol, sucrose, fructose, acacia syrup, alitame, sodium chloride, neohesperidine dihydrocbalcone, magnesium chloride, disodium inosinate, sodium L-glutamate, honey, cyclamate, cylamate, dextrose, calcium citrate, glycyrrhizin, sucrose, sugar, monosaccharides, oligosaccharides, aldose, ketose, maltose, lactose, xylitol, D-sorbitol, pentitol, hexitol, malitol, sodium cyclamate, maltol, mannitol, sorbitol, sylitol, isomalt, inulin, Prosweet® Powder, safrole, stevia, thaumatin, talin, monoammonium glyrrhizinate, glucose, and combinations thereof. Suitable flavorants include, but are not limited to, essential oils, peppermint oil, menthol, spearmint oil, citrus oil, cinnamon oil, strawberry flavor, cherry flavor, raspberry flavor, orange oil, apple, pear, peach, banana, Bavarian cream, caramel, cherry cream, chocolate, cinnamon, bubble gum, citrus, citrus punch, citrus cream, cotton candy, cocoa, cool cherry, camphor, cool citrus, eucalyptus, fruit punch, ginger, spearmint, spearmint cream, glycyrrhetinate, glycyrrhiza (licorice) syrup, grape, lemon, lemon cream, honey-lemon, lemon-lime, lemon-mint, lime, root beer, tutti frutti, walnut, watermelon, rum, anise, black currant, butterscotch, orange, cola, Swiss cream, mandarine, tangerine, grapefruit, vanilla, berry, mixed berry, raspberry, strawberry cream, wild cherry, maple, marshmallow, mint cream, Wintergreen, peppermint flavors, peppermint cream, methyl salicylate, eugenol, and combinations thereof. Additional suitable taste-masking agent include, but are not limited to, cellulose acetate, cellulose acetate butyrate, cellulose acetate phthalate (, ethylcellulose, hypromellose phthalate, hypromellose acetate succinate , poly(butyl methacrylic, (2-dimethylaminoethyl)methacrylate, methyl methacrylate) 1:2:1, poly(ethyl acrylate, methyl methacrylate) 2:1, poly(methacrylic acid, methylmethacrylate) 1:1, poly (methacrylic acid, ethyl acrylate) 1:1, poly (methacrylic acid, methyl methacrylate) 1:2, poly(methyl acrylate, methyl methacrylate, methacrylic acid) 7:3:1, poly(ethyl acrylate, methyl methacrylate, trimethylammonioethyl methacrylate chloride) l:2:0.2, polytethyl acrylate, methyl methacrylate, trimethylammonioethyl methacrylate chloride) 1:2:0.1, polyvinyl acetate, polyvinyl acetate phthalate, acetaldehyde (apple), benzaldehyde (cherry, almond), cinnamic aldehyde (cinnamon), citral, alpha citral (lemon, lime), neral, beta citral (lemon, lime), decanal (orange, lemon), ethyl vanillin (vanilla, cream), heliotropine, piperonal (vanilla, cream), vanillin (vanilla, cream), alpha-amyl cinnamaldehyde (spicy fruity flavors), butyraldehyde (butter, cheese), valeraldehyde (butter, cheese), citronella! (modifies, many types), decanal (citrus fruits), aldehyde C-8 (citrus fruits), aldehyde C-9 (citrus fruits), aldehyde C-12 (citrus fruits), 2-ethyl butyraldehyde (berry fruits), trans-2 hexenal (berry fruits), tolyl aldehyde (cherry, almond), veratraldehyde (vanilla), 2,6-dimethyl-5-heptenal, melonal (melon), 2-6-dimethyloctanal (green fruit), 2- dodecenal (citrus, mandarin), and mixtures thereof. The amount of taste-masking agent in the epinephrine prodrug ODTs of this disclosure can be from 0.1% to 25% (wt%), 0.5% to 25%, 1% to 25%, 2% to 25%, 5% to 25%, 10% to 25%, 0.1% to 20% (wt%), 0.5% to 20%, 1% to 20%, 2% to 20%, 5% to 20%, 10% to 20%, 0.1% to 10% (wt%), 0.5% to 10%, 1% to 10%, 2% to 10%, 5or 5% to 10%. In certain embodiments the taste masking agent is citric acid, sucralose, or saccharin, or a combination thereof.

[0045] The epinephrine prodrug ODT composition can optionally contain a chelating agent. Suitable chelating agents for the epinephrine prodrug ODTs of this disclosure include, but are not limited to, EDTA, a salt of EDTA, desferrioxamine B, deferoxamine, dithiocarb sodium, penicillamine, pentetate calcium, a sodium salt of pentetic acid, succimer, trientine, nitrilotriacetic acid, trans diaminocyclohexanetetraacetic acid (DCTA), diethylenetriaminepentaacetic acid, bis(aminoethyl)glycolether-N,N,N', N'- tetraacetic acid, iminodiacetic acid, citric acid, tartaric acid, fumaric acid, or a salt thereof. The amount of chelating agent in the epinephrine prodrug ODTs of this disclosure can be from 0.1% to 25% (wt%), including, e.g., 0.1% to 25%, 0.5% to 25%, 1% to 25%, 2% to 25%, 5% to 25%, 10% to 25%, 0.1% to 20%, 0.5% to 20%, 1% to 20%, 2% to 20%, 5% to 20%, 10% to 20%, 0.1% to 10%, 0.5% to 10%, 1% to 10%, 2% to 10%, or 5% to 10%.

[0046] The epinephrine prodrug ODT composition can optionally contain an antioxidant. Antioxidants suitable for the epinephrine prodrug ODTs of the present disclosure include, but are not limited to, butylated hydroxy anisole (BHA), butylated hydroxytoluene (BHT), ascorbic acid, methionine, sodium ascorbate, sodium thiosulfate, sodium bisulfite, sodium metabisulfite, ascorbyl palmitate, thioglycerol, alpha tocopherol (vitamin E), cysteine hydrochloride and combinations thereof.

[0047] The epinephrine prodrug ODT composition of the present disclosure can optionally contain a permeation enhancer. Permeation enhancers suitable for tire present disclosure include, but are not limited to, caprylic acid, oleic acid, polysorbate 80, menthol, EDTA, sodium edetate, cetylpyridinium chloride, benzylkonium chloride, essentials such as peppermint oi, clove oil, sodium lauryl sulfate, citric acid, sodium desoxycholate, sodium deoxyglycolate, glyceryl oleate, L - lysine, and combinations thereof.

[0048] The epinephrine prodrug ODT composi tion of the present disclosure can optionally contain a pH modifier. pH modifiers suitable for the present invention include, but tire not limited to, hydrochloric acid, citric acid, fumaric acid, lactic acid, sodium hydroxide, mono or dibasic sodium phosphate, amino acids, sodium citrate, sodium bicarbonate, sodium carbonate, ammonium carbonate and combinations of any of the foregoing. Typically, when dissolved in deionized water, the epinephrine prodrug ODT composition of this disclosure has a pH of from 1 - 7, in some embodiments a pH of from 1-5, and in some embodiments a pH of from 2.5 - 3.5.

[0049] The epinephrine prodrug ODTs can optionally contain a pharmaceutically acceptable colorant. Colorants suitable for the epinephrine prodrug ODTs of the present disclosure include, but tire not limited to, yellow, orange, red, green, and blue, colorants, or mixtures thereof. The epinephrine prodrug ODTs of this disclosure can optionally contain a coating, such as an immediate release coating.

[0050] The epinephrine prodrug ODTs can optionally contain a pharmaceutically acceptable filler. Fillers suitable for the epinephrine prodrug ODTs of the present disclosure include, but are not limited to, micro-crystalline cellulose, starches, lactose, sucrose, glucose, mannitol, sorbitol, xylitol, glucose, sugar, sugar derivates, calcium hydrogen phosphates, dicalcium phosphate, and mixtures thereof. The amount of filler in the ODTs can be from 1%' to 50% (wt%), including, e.g., 10% to 50%, 10% to 40%, 10% to 30%, 10%' to 20%, 15%' to 50%, 15% to 40%, 15% to 30%, 15% to 25%, 20% to 50%, 20% to 40%, 20% to 30%, 25% to 50%, 25%' to 40%, 25% to 35%', 30% to 50%, 30% to 40%, or 40% to 50%.

[0051] The epinephrine prodrug ODTs can optionally contain a pharmaceutically acceptable glidant. Glidants suitable for the epinephrine prodrug ODTs of the present disclosure include, but are not limited to, sterotes, magnesium stearate, calcium stearate, a hydrocarbon, mineral oil, hydrogenated castor oil, hydrogenated vegetable oil, hydrogenated soybean oil, silicone oil, a surfactant, stearic acid, sodium stearyl fumarate, macrogol, talc, sugar alcohols, solid polyethylene glycols, polyethylene glycol, methoxypolyethylene glycol magnesium or sodium lauryl sulfate, colloidal silica, sodium oleate, sodium benzoate, glyceryl behenate, glycerol, waxes, calcium hydroxide, silicon dioxide, starch, corn starch, colloidal silicon dioxide, and mixtures thereof. The amount of glidant in the ODTs can be from 1 % to 50% (wt%), including, e.g., 10% to 50%, 10% to 40%, 10% to 30%, 10% to 20%, 15% to 50%, 15% to 40%, 15%' to 30%, 15% to 25%', 20% to 50%, 20% to 40%, 20% to 30%, 25% to 50%, 25% to 40%, 25% to 35%, 30% to 50%, 30% to 40%, or 40% to 50%.

[0052] The epinephrine prodrug ODTs can optionally contain a pharmaceutically acceptable lubricant. Lubricants suitable for the epinephrine prodrug ODTs of the present disclosure include, but are not limited to, sterotes, magnesium stearate, calcium stearate, a hydrocarbon, mineral oil, hydrogenated castor oil, hydrogenated vegetable oil, hydrogenated soybean oil, silicone oil, a surfactant, stearic acid, sodium stearyl fumarate, macrogol, talc, sugar alcohols, solid polyethylene glycols, polyethylene glycol, methoxypolyethylene glycol magnesium or sodium lauryl sulfate, colloidal silica, sodium oleate, sodium benzoate, glyceryl behenate, glycerol, waxes, calcium hydroxide, silicon dioxide, starch, corn starch, colloidal silicon dioxide, and mixtures thereof. The amount of lubricant in the ODTs can be from 1% to 50% (wt%), including, e.g., 10% to 50%, 10% to 40%, 10% to 30%, 10% to 20%, 15% to 50%, 15% to 40%, 15% to 30%, 15% to 25%, 20% to 50%, 20% to 40%, 20% to 30%, 25% to 50%, 25% to 40%, 25% to 35%, 30% to 50%, 30% to 40%, or 40% to 50%.

[0053 ] The epinephrine prodrug GDI's can optionally contain a pharmaceutically acceptable diluent. Diluents suitable for the epinephrine prodrug ODTs of the present disclosure include, but are not limited to, lactose, starch, mannitol, sorbitol, dextrose, tricalcium phosphate, calcium phosphate, anhydrous lactose, spray-dried lactose, pregelatinized starch, compressible sugar, hydroxypropylmethylcellulose, hydroxypropylmethylcellulose acetate stearate, sucrose-based diluents, confectioner's sugar, monobasic calcium sulfate monohydrate, calcium sulfate dihydrate, calcium lactate trihydrate, dextrates, hydrolyzed cereal solids, amylose, powdered cellulose, calcium carbonate, glycine, kaolin, sodium chloride, and mixtures thereof. The amount of diluent in the ODTs can be from 1% to 50% (wt%), including, e.g., 10%' to 50%, 10% to 40%', 10% to 30%, 10% to 20%, 15% to 50%, 15% to 40%, 15% to 30%, 15% to 25%, 20% to 50%, 20% to 40%, 20% to 30%, 25% to 50%, 25% to 40%, 25% to 35%, 30% to 50%, 30% to 40%, or 40% to 50%.

[0054] In certain embodiments, the epinephrine prodrug ODTs are freeze dried tablets containing a binder, optionally a disintegrate, at least one matrix forming agent, also known as matrix former, and at least one taste masking agent. The taste masking agent can include a sweetener. Typical packaging of the freeze-dried epinephrine prodrug ODTs include aluminum blister packs. The blister pack comprises a multi-layered (e.g. 5 layers) laminated blister film and a lidding foil. The lidding foil is peelable such that the lidding foil over each tablet may be removed to reach the tablet.

[0055] The epinephrine prodrug ODTs can be manufactured by any of the manufacturing processes known in the art for preparing ODTs. For example, the epinephrine prodrug ODTs of this disclosure can be manufactured using conventional tableting process such as direct compression. The epinephrine prodrug ODTs can also be manufactured by wet granulation followed by drying the granules and compressing the granules into tablets. The epinephrine prodrug ODTs of the disclosure can be manufactured by a tablet molding process using water soluble excipients such as saccharides. Direct compression tablets of this disclosure typically contain a disintegrate.

[0056] In certain embodiments the total weight of the ODT is less than 100 mg, less than 70 mg, less than 50 mg, less than 40 mg, less than 30 mg, less than 20 mg, or less than 10 mg.

[0057] In certain embodiments the epinephrine prodrug orally disintegrating tablet dissolves completely in simulated saliva at 37 °C in less than 30 seconds, or less than 10 seconds or in less than 5 seconds.

[0058] In certain embodiments the epinephrine prodrug orally disintegrating tablet dissolves completely in water at ambient temperature in less than 30 seconds, or less than 10 seconds or in less than 5 seconds.

[0059] An aspect of the present disclosure relates to an epinephrine prodrug orally disintegrating tablet (ODT), comprising epinephrine prodrug, or a pharmaceutically acceptable salt thereof, a binder, a matrix former, and a taste masking agent, wherein tire tablet produces no detectable epinephrine when dissolved in fresh human saliva at 37° C. for 3 minutes, as determined by HPLC. [0060] In any aspect or embodiment described herein , the percent epinephrine is determined by HPLC, using the following conditions: C18 column, 3 μm, 100 mm x 4.6 mm, temperature 30° C, 254 nm detection, 1.0 mL/minute flow rate, 10 microliter injection volume, elution gradient:

[0061] Solvent A is 0.1% Trifluoroacetic acid (TFA) in H₂O,

[0062] Solvent B is 0.1 % TFA in acetonitrile, and the gradient from 0 to 12 minutes

[0063] In any aspect or embodiment described herein, the ODT comprises 0.01 mg to 20 mg epinephrine prodrug, or a pharmaceutically acceptable salt thereof, such as epinephrine prodrag hydrochloride.

[0064] In any aspect or embodiment described herein, the ODT comprises 0.5 mg, 1.0 mg, 2.5 mg, or 5 mg epinephrine prodrug or a pharmaceutically acceptable salt thereof, such as epinephrine prodrug hydrochloride.

[0065] In any aspect or embodiment described herein, the total weight of tire ODT is less than 50 mg.

[0066] In any aspect or embodiment described herein, the ODT comprises 10 to 70% binder (wt%), 5 to 50% matrix former (wt %), and 1 to 20% taste masking agent (wt%).

[0067] An further aspect of the present disclosure relates to an epinephrine prodrag orally disintegrating tablet (ODT), comprising not more than 63.5 mg epinephrine prodrug, or a pharmaceutically acceptable salt thereof (such as, epinephrine prodrug hydrochloride), a binder, a matrix former, and a taste masking agent, wherein the ODT provides an epinephrine T_max of less than 45 minutes and a plasma epinephrine C_max of 0.1 to 50 ng/mL, when administered to a dog or human.

[0068] In any aspect or embodiment described herein, the ODT contains not more than 5 mg of epinephrin prodrag or pharmaceutically acceptable salt thereof (e.g., epinephrin prodrug hydrochloride) and provides a plasma level of epinephrine at 20 minutes after administration that is equal or greater than a plasma level of epinephrine provided by a US FDA-approved injectable epinephrine dosage form, comprising 0.5 mg, epinephrine 0.3 mg epinephrine, 0.15 mg epinephrine, or 0.1 mg epinephrine.

[0069] In any aspect or embodiment described herein, the US FDA-approved injectable epinephrine dosage form is approved for intramuscular administration.

[0070] In any aspect or embodiment described herein, the US FDA-approved injectable epinephrine dosage form is approved for subcutaneous administration.

[0071] An additional aspect of the present disclosure relates to an epinephrine prodrug orally disintegrating tablet (ODT), comprising epinephrine prodrug, or a pharmaceutically acceptable salt thereof (such as, epinephrine prodrug hydrochloride), and 9- 53% gelatin (wt%), 20-40% glycine (wt%), 10-20% PVP K30 (wt%), 5-10% citric acid (wt%), and 5-10% saccharin sodium (wt%).

[0072] In any aspect or embodiment described herein, the ODT further comprises a permeation enhancer. For example, in any aspect or embodiment described herein, the permeation enhancer includes or is caprylic acid, oleic acid, polysorbate 80 (Polyethylene glycol sorbitan monooleate), menthol, ethylenedi aminetetraaceti c acid (EDTA), sodium edetate, cetylpyridinium chloride, sodium lauryl sulfate, citric acid, sodium desoxycholate, sodium deoxy glycolate, glyceryl oleate, L-lysine, or a mixture thereof.

[0073] Yet another aspect of the disclosure relates to an epinephrine prodrag orally disintegrating tablet (ODT), comprising epinephrine prodrug, or a pharmaceutically acceptable salt thereof (such as, epinephrine prodrug hydrochloride), a binder, a matrix former, a taste masking agent, and a penetration enhancer, wherein the tablet produces not more than 13 percent epinephrine when dissolved in fresh human saliva at 37° C for 11 minutes, as determined by HPLC.

[0074] In any aspect or embodiment described herein, the ODT comprises 0.01 mg to 20 mg epinephrine prodrug, or a pharmaceutically acceptable salt thereof (such as, epinephrine prodrug hydrochloride).

[0075] In any aspect or embodiment described herein, the ODT comprises 0.5 mg, 1.0 mg, 2.5 mg, or 5 mg epinephrine prodrug, or a pharmaceutically acceptable salt thereof (such as, epinephrine prodrag hydrochloride), wherein the total weight of the tablet is less than 50 mg.

[0076] In any aspect or embodiment described herein, the epinephrin prodrug is dipivefrin or L-dipivefrin. In any aspect or embodiment described herein, the epinephrin prodrug salt is dipivefrin hydrochloride or L-dipivefrin hydrochloride. [0077] In any aspect or embodiment described herein, the epinepbrin prodrug is not dipivefrin or L-dipivefrin. In any aspect or embodiment described herein, the epinephrin prodrug salt is not dipivefrin hydrochloride or L-dipivefrin hydrochloride. METHODS OF TREATMENT

[0078 ] The disclosure includes methods of treating a subject for a condition responsive to epinephrine by administering a epinephrine prodrug ODT of this disclosure to the subject.

[0079] Conditions responsive to epinephrine includes breathing difficulty, including breathing difficulties associated with anaphylaxis, asthma, bronchitis, emphysema, croup, or a respiratory infection.

[0080] Conditions responsive to epinephrine also include allergic attack, severe allergic symptoms, and anaphylaxis. Methods of treatment include administering a epinephrine prodrug ODT of this disclosure to a subject suffering from an allergic attack, severe allergies, or anaphylaxis. Methods of treatment of this disclosure also include administering a epinephrine prodrug ODT of this disclosure to a subject after the subject has been exposed to a known allergen, and thereby decreasing the risk of an allergic attack, severe allergies, or anaphylaxis or lessening the severity of from an allergic attack, severe allergies, or anaphylaxis. The epinephrine prodrug ODT can be administered as the only pharmaceutical agent or can optionally be administered together with another pharmaceutical agent such as an antihistamine or steroid. Examples of antihistamines include diphenhydramine, brompheniramine, cetirizine, chlorpheniramine, clemastine, fexofenadine, and loratidine.

[0081] Method of treatment includes administering an epinephrine prodrug ODT of the disclosure to a subject having insufficient epinephrine. Such a condition can be a chronic condition or an acute condition. Examples include Addison's disease, adrenal hyperplasia, hypoglycemia, and chronic active hepatitis.

[0082] The condition responsive to epinephrine can be cancer. The cancer can be skin cancer, brain cancer, a glioma, a sarcoma, breast cancer, lung cancer, non-small-cell lung cancer, mesothelioma, appendicular cancer, a genitourinary cancer, a renal cell carcinoma, prostate cancer, bladder cancer, testicular cancer, penile cancer, cervical cancer, ovarian cancer, von Hippel Lindau disease, a head and neck cancer, a gastrointestinal cancer, a hepatocellular carcinoma, gallbladder cancer, esophageal cancer, gastric cancer, colorectal cancer, pancreatic cancer, a neuroendocrine tumor, a thyroid tumor, a pituitary tumor, an adrenal tumor, a hematological malignancy, a lymphoma, a leukemia, or a combination thereof. The condition can be skin cancer, and the skin cancer is a melanoma. Epinephrine prodrug or its pharmaceutically acceptable salt can be an adjunctive anticancer treatment and the method comprises administering at least one additional anticancer treatment to the subject.

[0083] The condition responsive to epinephrine can be a microbial infection. The microbial infection can be a bacterial, viral, fungal, or parasitic infection. The microbial infection can be a viral infection, such as an influenza infection. The microbial infection can be a bacterial infection, such as a methicillin-resistant Staphylococcus aureus (MRS A) infection. Epinephrine prodrug or its pharmaceutically acceptable salt can be an adjunctive antimicrobial agent and the method further comprises the use of at least one additional antimicrobial agent for treating infection in the subject. The additional antimicrobial agent can be an antibiotic. The additional antimicrobial agent can be an antiviral agent.

[0084] The condition responsive to epinephrine can be an autoimmune disorder.

The autoimmune disorder can be rheumatoid arthritis, systemic lupus erythematosus (lupus), multiple sclerosis (MS), Type 1 diabetes mellitus, Guillain-Barre syndrome, chronic inflammatory demyelinating polyneuropathy, psoriasis, Graves' disease, Hashimoto's thyroiditis. Myasthenia gravis, vasculitis, and inflammatory bowel disease (IBD). Ulcerative colitis and Crohn's disease are the two major forms of IBD. Epinephrine prodrug or its pharmaceutically acceptable salt can be an adjunctive agent and the method further comprises the use of at least one additional pharmaceutical agent for treating an autoimmune disease in the subject. The additional pharmaceutical agent can include a steroid, immune-suppressing medicines, pyridostigmine, insulin or synthetic thyroid hormone.

[0085] Examples of the conditions responsive to epinephrine include croup, superficial bleeding, cardiac arrests, hypotension.

EXAMPLES

GENERAL METHODS

Simulated Saliva Composition

[0086] Table A provides the composition of simulated saliva used for in vitro evaluation of epinephrine prodrug ODTs. IN HC1 is used to adjust simulated saliva pH to 6.8.

In Vitro Dissolution Testing Method

[0087] An appropriate volume of simulated saliva needed to obtain a 1 mg/ml epinephrine prodrug HC1 concentration after dissolution is accurately weighed, placed in a glass vial and heated at 37 °C. One epinephrine prodrug HC1 ODT is dropped into the solution and gently swirled until the tablet is completely dissolved. The dissolution time is recorded.

HPLC analysis of epinephrine prodrug HC1 ODT

[0088] HPLC sample preparation: For epinephrine prodrug HC1 ODT 5.0 mg, 5.00 g of the simulated saliva was accurately weighed into a 20 mL glass scintillation vial. For epinephrine prodrug HC1 ODT 2.5 mg, 2.50 g of simulated saliva was used. The vials were placed in an oil bath set at 37 °C for 5 min. One tablet was placed in the appropriate vial which was gently swirled by hand until complete dissolution is achieved. The dissolution time was recorded. The dissolution samples were immediately analyzed by HPLC for purity and assay.

[0089] HPLC method:

Column: Phenomenex Gemini C18, 100 x 4.6 mm, 3.0 μm Flow rate: 1.0 mL/min

Detection: 254 nm

Temperature: 30 °C

Injection volume: 10 μL

Mobile phase: A: 0.1 % TFA in water

B: 0.1%' TFA in acetonitrile

Gradient:

[0090] The following examples illustrate preparation of epinephrine prodrug ODT formulations using dipivefrin HQ as the epinephrine prodrug.

EXAMPLE 1. PREPARATION OF EPINEPHRINE PRODRUG ODTS

[0091] The preparation of dipivefrin HC1 ODTs of various strengths is disclosed in this example. Diluent solution (pre-lyo solution minus epinephrine prodrug ODT) is prepared according to Table 1.1. To make a epinephrine prodrug ODT of a desired strength, the desired amount of epinephrine prodrug is dissolved in an appropriate amount of the diluent to obtain the epinephrine prodrug lyo solution. An aliquot of the lyo solution is then dispensed into blister pack pockets. The filled blister pack was then frozen on dry ice for at least one hour and freeze dried to obtain the epinephrine prodrug ODTs.

[0092] To prepare the diluent, gelatin is first dissolved in deionized water at about

40 °C to obtain a clear solution. The remaining excipients listed in Table 1.1 are then added and dissolved under stirring to obtain the diluent solution with pH 3.43. Dipivefrin is showh as a comparative example of an epinephrine prodrug. The structure of L-dipivefrin is:

Dipivefrin HC1 ODT 0.5 mg

[0093] Dipivefrin HC1 (5 mg) was dissolved in 5.30g of the diluent solution to obtain a lyo solution. The lyo solution (535 μl) was then dispensed into each pocket of a blister pack with a diameter of 13 mm and a depth of 3 mm resulting in a dose of 0.5 mg per tablet. The tablet blister pack was then placed on top of dry ice for one hour. The frozen tablets were freeze dried for 24 h using a VirTis Sentry 2.0 (SP Scientific) Freeze Dryer with a condenser temperature of -90 °C and a pressure of 50 mTorr. The lyophilized tablets were white, smooth, elegant and had sufficient strength for manual handling. Tablet weight: 29.87 mg+0,29 mg (SD, N=9). In vitro dissolution in simulated saliva at 37 °C: 2.30 seconds; In vivo dissolution time: 5.03 seconds; Dipivefrin HC1 assay by HPLC: 96.3%.

Dipivefrin HC1 ODT 1.0 mg

[0094] Dipivefrin HC1 (10 mg) was dissolved in 4.46g of the diluent solution to obtain a lyo solution. The lyo solution (446 μl) was then dispensed into each pocket of a blister pack with a diameter of 13 mm and a depth of 3 mm resulting in a dose of 1.0 mg per tablet. The tablet blister pack was then placed on top of dry ice for one hour. The frozen tablets were freeze dried for 24 h using a VirTis Sentry 2.0 (SP Scientific) Freeze Dryer with a condenser temperature of -90 °C and a pressure of 50 mTorr. The lyophilized tablets were white, smooth, elegant and had sufficient strength for manual handling. Tablet weight: 25.02 mg+0,33 mg (SD, N=10). In vitro dissolution in simulated saliva at 37 °C: 3.82 seconds; Dipivefrin HC1 assay by HPLC: 98.1 %.

Dipivefrin HC1 ODT 2.5 mg

[0095] Dipivefrin HC1 (25 mg) was dissolved in 5.30 g of the diluent solution to obtain a lyo solution. The lyo solution (535 μl) was then dispensed into each pocket of a blister pack with a diameter of 13 mm and a depth of 3 mm resulting in a dose of 2.5 mg per tablet. The tablet blister pack was then placed on top of dry ice for one hour. The frozen tablets were freeze dried for 24 h using a VirTis Sentry 2.0 (SP Scientific) Freeze Dryer with a condenser temperature of -90 °C and a pressure of 50 mTorr. The lyophilized tablets were white, smooth, elegant and had sufficient strength for manual handling. Tablet weight: 32.04 mg+0.42 mg (SD, N=9). In vitro dissolution in simulated saliva at 37 °C: 3.66 seconds; In vivo dissolution time: 3.86 seconds; Dipivefrin HC1 assay by HPLC: 98.8%.

Dipivefrin HC1 ODT 5.0 mg

[0096] Dipivefrin HC1 (50 mg) was dissolved in 5.30 g of the diluent solution to obtain a lyo solution. The lyo solution (535 μl) was then dispensed into each pocket of a blister pack with a diameter of 13 mm and a depth of 3 mm resulting in a dose of 2.5 mg per tablet. The tablet blister pack was then placed on top of dry ice for one hour. The frozen tablets were freeze dried for 24 h using a VirTis Sentry 2.0 (SP Scientific) Freeze Dryer with a condenser temperature of -90 °C and a pressure of 50 mTorr. The lyophilized tablets were white, smooth, elegant and had sufficient strength for manual handling. Tablet weight: 34.48 mg±0.51 mg (SD, N=9). In vitro dissolution in simulated saliva at 37 °C: 4.03 seconds. Dipivefrin HC1 assay by HPLC: 96.7%.

EXAMPLE 2. COMPARISON OF DIPIVEFRIN HCL ODTs CONTAINING SODIUM SACCHARIN AND

SUCRALOSE AS SWEETENERS

[0097] The effect of sweetener on the drying (final tablet weight) of dipivefrin HC1 ODTs is illustrated by this example. The diluent compositions are listed in Table 2.1 .

saccharin containing diluent (SS-diluent) and sucralose containing diluent (SU-diluent) were prepared at the same time in the same fashion as described in the Example 1. The tablets were removed from the blister packs, indi vidually weighed and stored in closed glass vials. One tablet from each group was tested for dissolution in simulated saliva at 37 °C at nominal drag concentration of 1.0 mg/ml. The clear solutions from the dissolution tests were analyzed by HPLC for purity assessment and dipivefrin HC1 assay. The results are summarized in Table 2.2, below. The sucralose containing dipivefrin HC1 ODTs were observed to have significantly higher weights than those containing sodium saccharin at the same dipivefrin strength (p<0 .0 5 for the 5 mg strength, p<0.01 for the 2.5 mg strength, two- tailed T-test). These results suggest that the dipivefrin HC1 lyo solution containing sodium saccharin dried more efficiently than that containing sucralose as the sweetener.

[0099] The 5 mg tablets containing sodium saccharin and sucralose were removed from the blister packs and assessed in side by side stability studies at 60 °C in closed glass vials. Stability data are summarized in Tables 2.3 and 2.4. The main degradants are a pair of monopivaloylepinephrine isomers as shown by LCMS, formed by partial ester hydrolysis of dipivefrin. Consistent with their higher tablet weight, the sucralose containing dipivefrin HC1

ODTs appeared to suffer from more hydrolytic degradation at 60 °C after 5 weeks.

EXAMPLE 3. PREPARATION OF DIPIVEFRIN HCL ODT FORMULATIONS FREE OF D-MANNITOL AND

STABILITY

[0100] This example reports the preparation of dipivefrin HQ ODTs that do not contain D-mannitol as the matrix forming agent and their in vitro dissolution property and stability. The diluent composition is shown in Table 3.1 below which gives a clear solution with a pH 2.99.

Dipivefrin HC1 ODT 5.0 mg

[0101] Dipivefrin HC1 (60.24 mg) was dissolved in 6.36 g of the diluent solution to obtain the lyo solution. The lyo solution (535 μl) was then dispensed into each pocket of a blister pack with a diameter of 13 mm and a depth of 3 mm resulting in a dose of 5.0 mg per tablet. The tablet blister pack was then placed on top of dry ice for one hour. The frozen tablets were freeze dried for 24 h using a VirTis Sentry 2.0 (SP Scientific) Freeze Dryer with a condenser temperature of -90 °C and a pressure of 50 mTorr. The lyophilized tablets were white, smooth, find elegant and had sufficient strength for manual handling. Tablet weight: 35.92 mg+0.59 mg (SD, N=11). In vitro dissolution in simulated saliva at 37 °C: 2.55 seconds. Dipivefrin HC1 assay by HPLC: 102.1%.

Dipivefrin HC1 ODT 2.5 mg

[0102] Dipivefrin HC1 (30.00 mg) was dissolved in 6.36 g of the diluent solution to obtain the lyo solution. The lyo solution (535 μl) was then dispensed into each pocket of a blister pack with a diameter of 13 mm and a depth of 3 mm resulting in a dose of 5.0 mg per tablet. The tablet blister pack was then placed on top of dry ice for one hour. The frozen tablets were freeze dried for 24 h using a VirTis Sentry 2.0 (SP Scientific) Freeze Dryer with a condenser temperature of -90 °C and a pressure of 50 mTorr. The lyophilized tablets were white, smooth, and elegant and had sufficient strength for manual handling. Tablet weight: 33.73 mg+0.48 mg (SD, N=11). In vitro dissolution in simulated saliva at 37 °C: 1 .92 seconds. Dipivefrin HQ assay by HPLC: 102.1%.

Dipivefrin HC1 ODT 1 .0 mg

[0103] Dipivefrin HCl (13.20 mg) was dissolved in 7.00 g of the diluent solution to obtain the lyo solution. The lyo solution (535 μl) was then dispensed into each pocket of a blister pack with a diameter of 13 mm and a depth of 3 mm resulting in a dose of 5.0 mg per tablet. The tablet blister pack was then placed on top of dry ice for one hour. The frozen tablets were freeze dried for 24 h using a VirTis Sentry 2.0 (SP Scientific) Freeze Dryer with a condenser temperature of -90 °C and a pressure of 50 mTorr. The lyophilized tablets were white, smooth, and elegant and had sufficient strength for manual handling. Tablet weight: 31.30 mg+0.62 mg (SD, N=11). In vitro dissolution in simulated saliva at 37 °C: 2.28 seconds. Dipivefrin HQ assay by HPLC: 100.1%.

Dipivefrin HQ ODT 0.5 mg

[0104] Dipivefrin HC1 (6.60 mg) was dissolved in 7.00 g of the diluent solution to obtain the lyo solution. The lyo solution (535 μl) was then dispensed into each pocket of a blister pack with a diameter of 13 mm and a depth of 3 mm resulting in a dose of 5.0 mg per tablet. The tablet blister pack was then placed on top of dry ice for one hour. The frozen tablets were freeze dried for 24 h using a VirTis Sentry 2.0 (SP Scientific) Freeze Dryer with a condenser temperature of -90 °C and a pressure of 50 mTorr. The lyophilized tablets were white, smooth, elegant and had sufficient strength for manual handling. Tablet weight: 32.24 mg±0.95 mg (SD, N=11). In vitro dissolution in simulated saliva at 37 °C: 2.02 seconds.

Dipivefrin HC1 assay by HPLC: 99.6%.

[0105] Both the 5mg and 2.5 mg tablets were removed from the blister packs and put on stability at 60 °C in closed glass vials. The 2 week stability data at 60 °C are summarized in Tables 3.2 and 3.3.

EXAMPLE 4. PREPARATION AND STABILITY TESTING OF DIPIVEFRIN HCL ODT FORMULATIONS CONTAINING EDTA

[0106] The diluent composition is shown in Table 4.1 below which gives a clear solution with pH 3.02.

Dipivefrin HC1 ODT 5.0 mg

[0107] Dipivefrin HC1 (66.4 mg) was dissolved in 7.00 g of the diluent solution to obtain the lyo solution. The lyo solution (535 μl) was then dispensed into each pocket of a blister pack with a diameter of 13 mm and a depth of 3 mm resulting in a dose of 5.0 mg per tablet. The tablet blister pack was then placed on top of dry ice for one hour. The frozen tablets were freeze dried for 24 hr at ambient and 60 °C for 20h using a VirTis Sentry 2.0 (SP Scientific) Freeze Dryer with a condenser temperature of -90 °C and a pressure of 50 mTorr. The lyophilized tablets were white, smooth, and elegant and had sufficient strength for manual handling. The tablets were removed from the blister packs, weighed individually and stored in a closed glass vial. Tablet weight: 28.76 mg+0.42 mg (SD, N=9). In vitro dissolution in simulated saliva at 37 °C: 1.56 seconds. Dipivefrin HCl assay by HPLC: 100.1 %.

Dipivefrin HC1 ODT 2.5 mg

[0108] Dipivefrin HC1 (33.0 mg) was dissolved in 7.00 g of the diluent solution to obtain the lyo solution. The lyo solution (535 μl) was then dispensed into each pocket of a blister pack with a diameter of 13 mm and a depth of 3 mm resulting in a dose of 5.0 mg per tablet. The tablet blister pack was then placed on top of dry ice for one hour. The frozen tablets were freeze dried for 24 hr at ambient and 60 °C for 20 hr using a VirTis Sentry 2.0 (SP Scientific) Freeze Dryer with a condenser temperature of -90 °C and a pressure of 50 mTorr. The lyophilized tablets were white, smooth, and elegant and had sufficient strength for manual handling. The tablets were removed from the blister packs, weighed individually and stored in a closed glass vial. Tablet weight: 24.23 mg±0.53 mg (SD, N=9). In vitro dissolution in simulated saliva at 37 °C: 1.52 seconds. Dipivefrin HC1 assay by HPLC: 93.0%.

[0109] The tablets were removed from the blister packs and assessed for stability at 60 °C in closed glass vials. The stability data are summarized in Tables 4.2 and 4.3.

EXAMPLE 5. DIPIVEFRIN HCL ODT FORMULATIONS STORED IN BLISTER PACKS WITH SILICA GEL PACKET

[0110] This example demonstrates that keeping the dipivefrin HC1 ODT tablets from moisture during preparation, packaging and handling is critical for their long term stability. The diluent composition was the same as that shown in Table 3.1 of Example 3. Dipivefrin HC1 ODT 5.0 mg

[0111] Dipivefrin HC1 (66.4 mg) was dissolved in 7.00 g of the diluent solution to obtain the lyo solution. The lyo solution (535 μl) was then dispensed into each pocket of a blister pack with a diameter of 13 mm and a depth of 3 mm resulting in a dose of 5.0 mg per tablet. The tablet blister pack was then placed on top of dry ice for one hour. The frozen tablets were freeze dried for 24 hr at ambient temperature. One tablet was removed from the blister pack and tested for in vitro dissolution, HPLC purity and HPLC assay (TO). The blister pack was then transferred to a vacuum oven connected to the freeze drier and dried at 60 °C for 1 week at a pressure of 86 mTorr. One tablet was removed and tested for appearance, in vitro dissolution, HPLC purity and HPLC assay (T 1 week at 60 °C). The remaining tablets were kept in the blister pack in a sealed plastic bag containing a 10g silica gel packet designed to protect an area of 91.5 cubic inch from moisture. The bags are stored both at ambient and 60 °C for long term stability testing. Dipivefrin HC1 ODT 2.5mg

[0112] Dipivefrin HC1 (33.2 mg) was dissolved in 7.00 g of the diluent solution to obtain the lyo solution. The lyo solution (535 μl) was then dispensed into each pocket of a blister pack with a diameter of 13 mm and a depth of 3 mm resulting in a dose of 5.0 mg per tablet. The tablet blister pack was then placed on top of dry ice for one hour. The frozen tablets were freeze dried for 24 hr at ambient. One tablet was removed from the blister pack and tested for in vitro dissolution, HPLC purity and HPLC assay (TO). The blister pack was then transferred to a vacuum oven connected to the freeze drier and dried at 60 °C for 1 week at a pressure of 86 mTorr. One tablet was removed and tested for appearance, in vitro dissolution, HPLC purity and HPLC assay (T 1 week at 60 °C). The remaining tablets were kept in the blister pack in a sealed plastic bag containing a 10g silica gel packet designed to protect an area of 91.5 cubic inch from moisture. The bags are stored both at ambient and 60 °C for stability testing.

[0113] The stability data are summarized in Tables 5.1 and 5.2. As the data shown, at 60 °C under high vacuum, both the 5 mg and 2.5 mg strength dipivefrin HC1 ODT showed no change in appearance, in vitro dissolution, HPLC purity and assay after 1 week. Since the main degradation pathway of dipivefrin is partial ester hydrolysis, without wishing to be bound by theory, the extraordinary stability of the dipivefrin ODTs at 60 °C is due to the absence of moisture under high vacuum. However, due to the highly porous nature of lyophilized tablets, the dipivefrin HC1 ODTs can absorb some moisture quickly from the air during their removal from the vacuum oven. This is consistent with the accelerated hydrolytic degradation observed in week 2 and apparent slowing down between weeks 2-4 possibly due to the decrease in water content after week 2.

EXAMPLE 6. INCUBATION OF DIPIVEFRIN HCL ODT IN FRESH HUMAN SALIVA AT 37 °C

[0114] This example demonstrates that dipivefrin HCI formulated as orally disintegrating tablets does not undergo significant hydrolysis in the oral cavity, in the short period of time which is typical for the administration of orally disintegrating tablets.

[0115] A dipivefrin HC1 lyo solution having a composition listed in Table 6.1 below was lyophilized in a blister pack (0.560 ml/pocket) to obtain dipivefrin HCI ODT 25 mg strength as described in Example 3. The tablets were elegant with good strength for manual handling and in vitro dissolution time of 26 seconds in simulated saliva at 37 °C.

[0116] About one quarter of the tablet was dissolved and incubated in 1 ml fresh human saliva at 37 °C for 11 min. An aliquot was diluted with deionized water, filtered through a 0.2 μm Nylon syringe filter and injected into HPLC. The analysis showed presence of about 13% epinephrine after incubation in saliva. In a separate experiment, about one quarter of the same tablet was incubated in 1 ml fresh human saliva at 37 °C for 3 min and

HPLC showed no detectable epinephrine after the incubation.

EXAMPLE 7. PREPARATION OF DIPIVEFRIN HCL ODT 63.5 MG FOR PHARMACOKINETICS STUDY

IN DOGS

[0117] A dipivefrin HC1 lyo solution having a composition listed in Table 7.1 below was lyophilized in a blister pack (0.594 mi/pocket) to obtain dipivefrin HC1 ODT 63.5 mg as described in Example 1. The tablet weight was 90.95+1.88 mg (SD, N=9).

EXAMPLE 8. PREPARATION OF DIPIVEFRIN HCL ODT 7.0 MG FOR PHARMACOKINETICS STUDY

IN DOGS

[0118] A dipivefrin HC1 lyo solution having a composition listed in Table 8.1 below was lyophilized in a blister pack (0.535 ml/pocket) to obtain dipivefrin HC1 ODT 5.0 mg as described in Example 1 . The tablets were white and had elegant appearance with pleasant taste. Weight: 34.97+0.42 mg (SD, N=9). In vitro dissolution time in simulated saliva at 37

°C: 4.90 seconds.

EXAMPLE 9. PHARMACOKINETIC STUDIES OF DIPIVEFRIN HCL ODT AFTER SINGLE ORAL ADMINISTRATION IN DOGS (N=3)

[0119] Pharmacokinetics of dipivefrin HC1 was evaluated in dogs in a three leg cross-over design according to Table 9.3 below. Four days prior to study initiation, 1 mL of whole blood was collected from four (n=4) non-naïve male Beagle dogs, aged 1.5-6.5 years and ranging from 9.8 to 10.8 kilograms in weight, into 4 chilled tubes containing K2EDTA. The blood was processed to plasma and plasma cholinesterase activity was assayed according to the Ellman method using acetylthiocholine iodide as the substrate (Ellman, G. L. et al Biochemical Pharmacology, 1961 , volume 7, page 88-95), The assay results are summarized in Table 9.1. Based on the plasma cholinesterase activity assay results, the first three dogs with highest plasma cholinesterase activity were selected for the PK study.

[0120] Dogs were housed one per cage and identified by ear tags and cage labels. The animals were healthy at the start of the study. Primary enclosures were as specified in the USDA Animal Welfare Act (9 CFR, Parts 1 , 2, and 3) and as described in the Guide for Care and Use of Laboratory Animals (ILAR publication, 2011, National Academy Press). Animals were fasted for a minimum of 12 hours prior to dosing and returned 4 hours post dose; Water was supplied ad libitum to the animals.

[0121] Dosing occurred at 0 hours on the appropriate day in accordance with the Study Design table (Table 9.3). The first leg of epinephrine IM 0.3 mg (Composition shown in Table 9.2), standard care for anaphylaxis, is included as a control. The intramuscular dose was administered via 25 gauge needle and syringe into the lateral aspect of the left or right thigh. The dosing site was clipped free of hair and cleaned with alcohol prior to dosing. The orally disintegrating tablets were dosed by placing one tablet on the tongue of the dog. The muzzle was gently held closed for 1-2 minutes. After this period, the mouth was opened to observe that the tablet had completely dissolved.

[0122] Whole blood samples (~0.5 to 1 mL) were collected from the dog's jugular vein via direct venipuncture at the appropriate time point and placed into K2EDTA tubes as the anticoagulant. Blood samples were centrifuged at a temperature of 4°C at 3000g for 5 minutes. All samples were maintained chilled throughout processing. Plasma samples (250 pL) were aliquoted into 50uL of 6% wt sodium metabisulfite solution in an eppendorf tube, and placed in a freezer set to maintain ~ -70°C until shipment in dry ice to the Keystone Bioanalytical for analysis of plasma concentrations of epinephrine.

[0123] The PK analysis results of dipivefrin HQ in dogs were summarized below (Table 9.4). The statistical analyses were performed using one-way ANOVA followed by Turkey's multiple comparisons test. All statistical analyses were performed using Prism 7.0 (GraphPad Software, San Diego, CA).

C_max: maximum plasma concentration (mean +SEM of individual dog Cmax values); Tmax: time at which maximum plasma epinephrine concentration was achieved (mean +SEM of individual dog Tmax values); AUCO-last: area under the plasma concentration versus time curve (mean +SEM of individual dog AUG values). T_max is the time at which the highest peak epinephrine concentration occurred in each individual dog. T_max is limited by experimental design because it is a discrete variable based on defined times of blood sampling.

[0124] After administration of dipivefrin HC1 orally disintegrating tablet to beagle dogs, plasma epinephrine concentration rises rapidly. The dipivefrin HC1 orally disintegrating 5 mg tablet dose provided 2 times of C_max and AUC_last compared to the epinephrine standard IM 0.3 mg injection with comparable T_max. Dipivefrin HC1 63.6 mg produced significantly higher levels of epinephrine when compared to either the 5mg dipivefrin HC1 orally disintegrating tablet (p<0.05 for C_max and p<0.01 for AUC) or the standard epinephrine IM 0.3 mg (p<0.01 for both C_max and AUC). The mean plasma epinephrine vs time profiles are shown in FIG. 1 and FIG 2. There is no significant difference in T_max among all treatment groups (p>0.6). This example demonstrates that a dipivefrin HC1 ODT can produce statistically equivalent levels of epinephrine in dogs as the standard epinephrine IM 0.3 mg, a drug of choice for emergency treatment of anaphylaxis. EXAMPLE 10. PHARMACOKINETIC STUDIES OF DIPIVEFRIN HCL ODT' AFTER SINGLE ORAL ADMINISTRATION IN DOGS (N=6)

[0125] Pharmacokinetics of dipivefrin HC1 was evaluated in six dogs in a three leg cross-over design according to Table 10.3 below. Four days prior to study initiation, 1 mL of whole blood was collected from seven (n-7) non-naive male Beagle dogs, aged 1.5-6.5 years and ranging from 10.6 to 13.75 kilograms in weight, into 7 chilled tubes containing K2EDTA. The blood was processed to plasma and plasma cholinesterase activity was assayed according to the Ellman method using acetylthiocholine iodide as the substrate (Ellman, G. L. et al Biochemical Pharmacology, 1961 , volume 7, page 88-95). The assay results are summarized in Table 10.1. Based on the plasma cholinesterase activity assay results, the top six dogs with highest plasma cholinesterase activity were selected for the PK study.

[0126] Dogs were housed one per cage and identified by ear tags and cage labels. The animals were healthy at the start of the study. Primary enclosures were as specified in the USDA Animal Welfare Act (9 CFR, Parts 1, 2, and 3) and as described in the Guide for Care and U se of Laboratory Animal s (1LAR publication, 2011 , National Academy Press). Animals were fasted for a minimum of 12 hours prior to dosing and returned 4 hours post dose; Water was supplied ad libitum to the animals.

[0127] Dosing occurred at 0 hours on the appropriate day in accordance with the Study Design table (Table 10.2). The first leg of epinephrine IM 0.3 mg (Composition shown in Table 9.2), standard care for anaphylaxis, is included as a control. The intramuscular dose was administered via 25 gauge needle and syringe into the lateral aspect of the left or right thigh. The dosing site was clipped free of hair and cleaned with alcohol prior to dosing. The orally dissolving tablets (compositions shown in Table 10.2) were dosed by placing one tablet on the tongue of the dog. The muzzle was gently held closed for 1-2 minutes. After this period, the mouth was opened to observe that the tablet had completely dissolved.

[0128] Whole blood samples (~0.5 to 1 mL) were collected from the dog's jugular vein via direct venipuncture at the appropriate time point and placed into K₂EDTA tubes as the anticoagulant. Blood samples were centrifuged at a temperature of 4°C at 3000g for 5 minutes. All samples were maintained chilled throughout processing. Plasma samples (250 μL) were aliquoted into 50uL of 6% wt sodium metabisulfite solution in an eppendorf tube, and placed in a freezer set to maintain - -70°C until shipment in dry ice to the Keystone Bioanalytical for analysis of plasma concentrations of epinephrine.

[0129] The PK analysis results of dipivefrin HC1 in dogs were summarized below (Table 10.4). The statistical analyses were performed using one-way ANOVA followed by Turkey's multiple comparisons test. All statistical analyses were performed using Prism 7.0 (GraphPad Software, San Diego, CA).

C_max : maximum plasma concentration (mean ± SD of individual dog Cmax values);

Tmax: time at which maximum plasma epinephrine concentration was achieved (mean + SD of individual dog Tmax values); AUCO-last: area under the plasma concentration versus time curve (mean + SD of individual dog AUG values). T_max is the time at which the highest peak epinephrine concentration occurred in each individual dog. T_max is limited by experimental design because it is a discrete variable based on defined times of blood sampling.

[0130] The mean plasma epinephrine vs time profiles are shown in FIG. 3. This example demonstrates that a dipivefrin HC1 ODT can produce similar levels of epinephrine in dogs as the standard epinephrine IM 0.3 mg, a drug of choice for emergency treatment of anaphylaxis.

EXAMPLE 11. PREPARATION OF DIPIVEFRIN HCL ODT FORMULATIONS OF FLEXIBLE TABLET

SIZES

[0131] The purpose of this example is to illustrate the flexibility of the subject invention with regards to tablet size at the same strength. For example, smaller tablets can be conveniently made by simply increasing the amount of API while keeping the amount of inactive ingredients the same in the solution mix prior to lyophilization; higher API content requires smaller dose weight per blister pocket producing smaller tablets after freeze drying. The amount of each inactive ingredient can also be easily adjusted (Table 11.1).

Claims

CLAIMS What is claimed is:

1. An epinephrine prodrug orally disintegrating tablet (ODT), comprising epinephrine prodrug, a pharmaceutically acceptable salt thereof, a binder, a matrix former, and a taste masking agent.

2. The epinephrin prodrug ODT of claim 1, wherein the epinephrine prodrug is a compound of the formula

or a pharmaceutically acceptable salt thereof wherein

R¹, R², R', and R⁴ are independently chosen from H, C₁-C₁₂alkylcarbonyl, mono or di- C₁-C₁₂alkylaminocarbonyl, C₁-C₁₂alkoxycarbonyl, (C₃-C₆cycloalkyl)C₀-C₄alkylcarbonyl, phenylC₀-C₄alkylcarbonyl, (C₀-C₁₂alkyl)sulfate, and (C₀-C₁₂alkyl)phosphate;

Where each alkyl or alkoxy in the definition of R³ optionally contains one or more double or triple bonds, has one or more CH₂ groups replaced by O, S, NH, or NR³ where R⁵ is C₁-C₆alkyl, and is optionally substituted with one or more substituents independently chosen from halogen, hydroxyl, nitro, amino, oxo, or cyano;

Where the R ^l alkyl or alkoxy may be joined to the R² alkyl or alkoxy to form a 5 to 7- membered ring or the R alkyl or alkoxy may be joined to the R" alkyl or alkoxy to form a 5- to 7-membered ring; and

Where not all of R¹, R², R³, and R⁴ are H, and dipivefrin (R¹ and R² = pivaloyl group, R³ = R⁴ = H) is excluded.

3, The ODT of claim 1, comprising 0.01 mg to 20 mg epinephrine prodrug hydrochloride.

4. The ODT of claim 1, comprising 0.5mg, 1.0 mg, 2.5 mg, or 5 mg or 15 nig epinephrine prodrug hydrochloride.

5. The ODT of any one of claims 1 to 4, wherein the total weight of the tablet is less than 50 mg.

6. The ODT of any one of claims 1 to 5, comprising at 10 to 70% binder (wt%), 5 to

50% matrix former (wt%), and 1 to 20% taste masking agent (wt%).

7. The ODT of any one of claims 1 to 6, wherein the matrix former comprises mannitol or glycine.

8. The ODT of any one of claims 1 to 7, wherein the taste masking agent comprises a sweetener.

9. The ODT of any one of claims 1 to 8, wherein the binder comprises gelatin and povidone.

10. The ODT of any one of claims 1 to 9, additionally comprising EDTA and or benzalkonium chloride.

11. The ODT of any one of claims 1 to 10, wherein the ODT provides an epinephrine T_max of less than 45 minutes when administered to a human.

12. The ODT of any one of claims 1 to 11, wherein the ODT provides an epinephrine plasma C_max of 0.1 to 50 ng/mL when administered to a human.

13. The ODT of any one of claims 1 to 10, wherein the ODT contains not more than 10 mg of dipivefrin hydrochloride and provides a plasma level of epinephrine at 20 minutes after administration that is equal or greater than a plasma level of epinephrine provided by a US

FDA-approved injectable epinephrine dosage form.

14. The ODT of claim 13, wherein the US FDA-approved dosage form comprises a 0.5 mg, 0.3 mg, 0.15 mg, or 0.1 mg epinephrine dosage form for intramuscular administration.

15. The ODT of claim 13, wherein the US FDA-approved dosage form comprises a 0.5 mg, 0.3 mg, 0.15 mg, or 0.1 mg epinephrine dosage form for subcutaneous administration.

16. The ODT of any one of claims 1 to 13, wherein the epinephrine prodrug is L- epinephrine prodrag hydrochloride.

17. A method of treating a subject suffering from a condition responsive to epinephrine comprising administering the ODT of any one of claims 1 to 16 to the subject.

18. The method of claim 17, wherein the condition responsi ve to epinephrine is a breathing difficulty.

19. The method of claim 1 /, wherein the breathing difficulty is associated with associated with anaphylaxis, asthma, bronchitis, emphysema, croup, or a respiratory infection.

20. The method of claim 17, wherein the condition is anaphylaxis.

21 . A method of reducing the severity of an allergic reaction or anaphylaxis or inhibiting the onset of an allergic reaction or anaphylaxis in a subject, comprising administering the ODT of any one of claims 1 to 15 to the subject following exposure of the subject to an allergen.

2.2. The method of any one of claims 17 to 21, additionally comprising administering an antihistamine to the subject.

23. The method of claim 22, wherein the antihistamine is diphenhydramine.

24. The method of claim 17 wherein the condition is Addison's disease, adrenal hyperplasia, hypoglycemia, or chronic active hepatitis.

2.5. The method of claim 17 wherein the condition is cancer.

26. The method of claim 17 wherein the condition is an autoimmune disorder.

27. The method of claim 17 wherein the condition is a microbial infection.