WO2022223522A1

WO2022223522A1 - Extended and controlled release formulation of apomorphine

Info

Publication number: WO2022223522A1
Application number: PCT/EP2022/060254
Authority: WO
Inventors: Francesco Trotta; Alessandro MAURO; Roberta Cavalli; Lorenzo PRIANO; Stefania CATTALDO
Original assignee: Universita' Degli Studi Di Torino; Istituto Auxologico Italiano - Irccs
Priority date: 2021-04-19
Filing date: 2022-04-19
Publication date: 2022-10-27
Also published as: IT202100009857A1; EP4326238A1

Abstract

The present invention provides an extended and controlled release formulation comprising at least one apomorphine loaded nanosponge of:- apomorphine or a pharmaceutically salt thereof, and - a cross-linked polymer of i) a dextrin or ii) amaltodextrin deriving from starch comprising amylose in the range from 25 to 50% expressed as dry weight relative to the dry weight of the starch with a cross-linking compound selected from the group consisting of a dianhydride, sodium trimetaphosphate and citric acid; and an optional pharmaceutically acceptable vehicle.

Description

EXTENDED AND CONTROLLED RELEASE FORMULATION OF APOMORPHINE

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FIELD OF THE INVENTION

The present invention relates to an extended and controlled release formulation of apomorphine comprising at least one apomorphine loaded nanosponge or a pharmaceutically acceptable salt thereof with a cross-linked polymer also known as nanosponge and an optional pharmaceutically acceptable vehicle.

BACKGROUND OF THE INVENTION

Apomorphine is a type of aporphine having activity as a non-selective dopamine agonist which activates both D2-like and, to a much lesser extent, D1 -like receptors. It also acts as an antagonist of 5-HT2 and a-adrenergic receptors with high affinity. Apomorphine is known as a drug useful for the treatment of Parkinson’s disease and is also known for its very susceptibility to oxidative degradation.

In fact, Apomorphine as an effective agonist at both dopamine receptors in the nervous system, has been used for treatment of Parkinson's disease in patients that have become resistant to or have developed adverse side effects with associated with chronic levodopa therapy. Typically, due to its short duration of effectiveness, apomorphine is administered by repeated subcutaneous injections or continuous parenteral infusion via a pump. These means of administration are inconvenient, in the case of subcutaneous injection, and technically difficult, in the case of pump administration, especially for Parkinson's patients whose dexterity is impaired due to the disease itself and the movements associated with chronic levodopa treatment. Apomorphine may also be administered transdermally (U.S. Pat. No. 5,562,917), intranasally (U.S. Pat. No. 5,756,483), as a topically-applied gel (U.S. Pat. No. 5,939,094), or sublingually (U.S. Pat. No. 5,994,363). None of these methods permits continuous administration over long periods of time.

Therefore, apomorphine is only administered parenterally (subcutaneous injection or infusion) for its low oral bioavailability and high hepatic “first pass” metabolism. Many approaches have been proposed so far for improving the therapeutic index of apomorphine, including new kind of therapeutic delivery systems.

Apomorphine released from the known commercial formulations has an extensive hepatic first pass metabolism leading to low oral bioavailability and a therapeutic effect lasting no longer than 40 minutes.

There is still a need for an improved means of increasing bioavailability and so the administration that would permit continuous dosing of dopamine agonists over an extended period of time of several months or longer, without the adverse side effects associated with peaks and troughs in plasma levels due to discontinuous dosing, or reliance on cumbersome mechanical equipment such as a pump.

Therefore, the object of the present invention is to provide an extended and controlled release formulation of apomorphine so overcoming the drawbacks of the prior art documents.

SUMMARY OF THE INVENTION

The inventors surprisingly found out that nanosponges can load apomorphine and enable its administration in a controlled and extended way. Owing to the invention, therefore brilliantly apomorphine can be administered by different routes, including oral, topical, parenteral and nasal one, since according to the invention the bioavailability of apomorphine was surprisingly increased avoiding its degradation. As it will more evident from below a number of nanosponge nanostructure, either cyclodextrin- based or dextrin-based, showed the capability to incorporate and protect from degradation (oxidation) apomorphine and to increase its bioavailability and hence allow to prepare an extended and controlled release formulation . Therefore, the invention relates to an extended and controlled release formulation comprising at least one apomorphine loaded nanosponge of

- apomorphine or a pharmaceutically salt thereof, and

- a cross-linked polymer of i) a dextrin or ii) a maltodextrin deriving from starch comprising amylose in the range from 25 to 50% expressed as dry weight relative to the dry weight of the starch with a cross-linking compound selected from the group consisting of a dianhydride, sodium trimetaphosphate and citric acid; and an optional pharmaceutically acceptable vehicle.

The pharmaceutical formulation according to the invention allowed that apomorphine in nanosponges resulted surprisingly in vitro released with controlled and sustained kinetics.

In another aspect the invention relates to a method for improving the bioavailability of apomorphine by avoiding its oxidative degradation by using the pharmaceutical formulation of the invention.

In a still another aspect the invention relates to a pharmaceutical formulation for use in the treatment of Parkinson’s disease.

DESCRIPTION OF THE FIGURES:

Figure 1 shows the apomorphine calibration curve of Example 3;

Figure 2 shows the result of the evaluation of example 3 regarding the chemical stability of apomorphin in b-CD-PMDA nanosponges;

Figure 3 shows the graph of the in vitro release of apomorphine b-CD-PMDA nanosponge at different pH;

Figure 4 shows the graph of the in vitro drug release kinetics of apomorphine LC- CIT, LC-STMP and b-CD-PMDA, nanosponges at pH= 6.8;

Figure 5 shows the graph of apomorphine plasma concentration over time after administration of the drug in b-CD-PMDA nanosponges (solid line) and apomorphine solution (dashed line)

DETAILED DESCRIPTION OF THE INVENTION

Therefore, the invention relates to an extended and controlled release formulation comprising at least one apomorphine loaded nanosponge of:

- apomorphine or a pharmaceutically salt thereof, and

In the present invention when the following terms are used:

- “nanosponge” it is meant the cross-linked polymer of the invention in the form of a particle. In general, the average diameter of said cross-linked particles is in the range of 1 to 1000 nm. This average diameter is a hydrodynamic diameter. It can be for instance determined by the person skilled in the art by Laser Light Scattering. In general, such particles are insoluble in water at room temperature (20°C-25°C).

- “starch” classically refers to the starch isolated from any suitable botanical source, by any technique well known to those skilled in the art. Isolated starch typically contains not more than 3% of impurities; said percentage being expressed in dry weight of impurities with respect to the total dry weight of isolated starch. These impurities typically comprise proteins, colloidal matters and fibrous residues. Suitable botanical source includes for instance legumes, cereals, and tubers. As above indicated a starchy material is a product obtained by starch.

The formulation of the invention comprises apomorphine or a pharmaceutically acceptable salt.

The pharmaceutical formulation comprises a cross-linked polymer of i) a dextrin or ii) a maltodextrin deriving from starch comprising amylose in the range from 25 to 50% expressed as dry weight relative to the dry weight of the starch with a cross- linking compound selected from the group consisting of a dianhydride, sodium trimetaphosphate and citric acid.

In a first preferred embodiment, the pharmaceutical formulation comprises of i) a dextrin with a cross-linking compound selected from the group consisting of a dianhydride, sodium trimetaphosphate and citric acid.

The dextrin according to the invention can be a linear dextrin or a cyclodextrin. This latter is a natural or semi-synthetic cyclic oligosaccharide, being generally biodegradable. Preferably, When the dextrin is a cyclodextrin, it can be a-cyclodextrin, b-cyclodextrin or g-cyclodextrins. Preferably the dextrin i) of the invention is b-cyclodextrin.

In another preferred embodiment the pharmaceutical formulation comprises a cross- linked polymer of ii) a maltodextrin deriving from starch comprising amylose in the range from 25 to 50% expressed as dry weight relative to the dry weight of the starch with a cross-linking compound selected from the group consisting of a dianhydride, sodium trimetaphosphate and citric acid.

The expression “maltodextrin” classically refers to the starchy material obtained by acid and/or enzymatic hydrolysis of starch. The present invention hence relates to a pharmaceutically formulation comprising a cross-linked polymer obtainable by reacting ii) a maltodextrin deriving from starch comprising amylose in the range from 25 to 50% expressed as dry weight relative to the dry weight of the starch. Preferably the maltodextrin of the invention derives from leguminous starch. By "leguminous" is meant within the meaning of the present invention any plant belonging to the families of the Caesalpiniaceae, Mimosaceae or Papilionaceae and notably any plant belonging to the family of the Papilionaceae such as, for example, pea, bean, broad bean, horse bean, lentil, lucerne, clover or lupin. This definition includes in particular all the plants described in any one of the tables contained in the article by R. HOOVER et al. , 1991 (HOOVER R. (1991) "Formulation, structure, functionality and chemical modification of leguminous starches: a review" Can. J. Physiol. Pharmacol., 69, pp. : 79-92). Preferably, the leguminous plant is chosen from the group formed by the pea, bean, broad bean, horse bean and their mixtures. According to a preferred and advantageous embodiment, the leguminous plant is a variety of pea or horse bean, producing seeds containing at least 25%, preferably at least 40%, by weight of starch (dry/dry). More advantageously, said leguminous plant is the pea. The term "pea" being here considered in its broadest sense and including in particular: all the wild "smooth pea" varieties and all the mutant "smooth pea" and "wrinkled pea" varieties, irrespective of the uses for which said varieties are generally intended (human consumption, animal nutrition and/or other uses). The leguminous starch of the invention preferably has an amylose content in the range from 30% to 40%, preferably from 35% to 40%, more preferably from 35% to 38%, these percentages being expressed as dry weight relative to the dry weight of starch.

The maltodextrins are conventionally obtained by acid and/or enzymatic hydrolysis of starch. Referring to the regulatory status, the maltodextrins have a dextrose equivalent (DE) of 1 to 20.

Preferably in the present invention the maltodextrin has a dextrose equivalent (DE) of 17 and an average molecular weight by weight of about 12000 D.

Suitable maltodextrins are commercially available, for instance those marketed under the name KLEPTOSE® Linecaps (LC) (ROQUETTE) or GLUCIDEX® (ROQUETTE).

The cross-linked polymer contained in the pharmaceutical formulation of the invention is preferably of i) a b- cyclodextrin or ii) a maltodextrin deriving from pea starch with a cross-linking compound selected from the group consisting of a dianhydride, sodium trimetaphosphate and citric acid.

The crosslinking compound hence is selected from the group consisting of a dianhydride, sodium trimetaphosphate and citric acid. Preferably, it is a dianhydride. Among the dianhydrides, in the present invention the following dianhydrides can be used: diethylenetriaminepentaacetic dianhydride, ethylenediaminetetraacetic dianhydride, benzophenone-3,3',4,4'-tetracarboxylic dianhydride, and pyromellitic dianhydride. More preferably the cross-linking compound is pyromellitic dianhydride.

The cross-linked polymer, i.e. the nanosponge, of the pharmaceutical formulation can be obtained by reacting either i) a b- cyclodextrindextrin or ii) a maltodextrin with a cross-linking compound selected from the group consisting of a dianhydride, sodium trimetaphosphate and citric acid in a ratio in the range of the compound i) or ii) with respect to the cross-linking compound in the range from 1 :2 to 1 :12.

The pharmaceutical formulation of the invention can be obtained by the loading of apomorphine on preformed nanosponges, generally dispersed as aqueous nanosuspension, in the presence of antioxidants and suitable excipients. The apomorphine impregnation can be obtained also with the slurry method. After the loading process the aqueous nanosponge nanosuspension is freeze-dried to obtain a dry powder.

Each cross-linked polymer is a nanosponge in the form of a solid particle.

The final pharmaceutical formulation comprises apomorphine loaded in the crosslinked polymer compound, i.e. an apomorphine-loaded nanosponge having specific physical characteristics. The final pharmaceutical formulation comprises hence a plurality of particles of apomorphine-loaded nanosponges.

The final pharmaceutical formulation comprises at least one apomorphine-loaded nanosponge having specific physical characteristics.

Preferably the apomorphine-loaded nanosponge, i.e. the least one apomorphine loaded nanosponge is selected from apomorphine-p-CD-PMDA (Pyromellitic dianhydride) nanosponge, apomorphine-Linecaps-citric acid nanosponge and apomorphine-Linecaps-STMP (sodium trimetaphosphate (STMP) nanosponge. Advantageously, apomorphine-p-CD-PMDA (Pyromellitic dianhydride) nanosponge has an average diameter from 150 nm to 600 nm; a polydispersity index from 0.1 to 0.35; and a Zeta potential from - 10 mV to - 30 mV; apomorphine-Linecaps-citric acid nanosponge has an average diameter from 200 nm to 700 nm; a polydispersity index from 0.1 to 0.4; and a Zeta potential from - 10 mV to - 30 mV apomorphine- Linecaps-STMP (sodium trimetaphosphate (STMP) nanosponge has an average diameter from 100 nm to 500 nm; a polydispersity index from 0.1 to 0.3; and a Zeta potential from - 10 mV to -40 mV.

The apomorphine loading capacity of the apomorphine ranged from 2% to 20% and the encapsulation efficiency ranged from 90 % to 99 % for all apomorphine loaded nanosponges.

The pharmaceutical composition comprises hence apomorphine dispersed in the crosslinked polymer compound, i.e. an apomorphine-loaded nanosponge and an optional pharmaceutically acceptable vehicle.

This latter can be preferably water or aqueous solutions or hydrogels.

The pharmaceutical formulation according to the invention hence allowed that apomorphine in nanosponges resulted surprisingly in vitro released with controlled and sustained kinetics.

The invention relates also to the pharmaceutical formulation for use as a medicament.

The pharmaceutical formulation of the invention may be administered by any suitable route of administration, including both systemic administration and topical administration.

Systemic administration includes oral administration, parenteral administration, trans-dermal administration, rectal administration, and administration by inhalation. The extended and controlled release formulation of the invention may be administered once or according to a dosing regimen wherein a number of doses are administered at varying intervals of time for a given period of time as prescribed for treating the disease. The pharmaceutical formulations of the invention may be prepared and packaged in bulk form or may be prepared and packaged in unit dosage form. A dose of the pharmaceutical formulation contains at least a therapeutically effective amount of apomorphine.

The pharmaceutical formulation can contain also one or more pharmaceutically acceptable excipient.

Conventional dosage forms include those adapted for (1) oral administration such as tablets, capsules, caplets, pills, troches, powders, syrups, elixirs, suspensions, solutions, emulsions, sachets, and cachets; (2) parenteral administration such as sterile solutions, suspensions, and powders for reconstitution; (3) trans-dermal administration such as trans-dermal patches; (4) rectal administration such as suppositories; (5) inhalation such as aerosols and solutions; and (6) topical administration such as creams, ointments, lotions, pastes, sprays and gels.

Suitable pharmaceutically acceptable excipients include the following types of excipients: diluents, fillers, binders, disintegrants, lubricants, granulating agents, coating agents, wetting agents, suspending agents, emulsifiers, sweeteners, flavour masking agents, colouring agents, anti-caking agents, humectants, plasticizers, viscosity increasing agents, antioxidants, preservatives, stabilizers, surfactants, and buffering agents. Suitable diluents and fillers include lactose, sucrose, dextrose, mannitol, sorbitol, starch, cellulose, calcium sulphate, and dibasic calcium phosphate. The oral solid dosage form may further comprise a binder. Suitable binders include gelatine, sodium alginate, alginic acid, guar gum, povidone, and cellulose and its derivatives (e.g. microcrystalline cellulose). The oral solid dosage form may further comprise a disintegrant. Suitable disintegrants include crospovidone, sodium starch glycolate, alginic acid, and sodium carboxymethyl cellulose. The oral solid dosage form may further comprise a lubricant. Suitable lubricants include stearic acid, magnesium stearate, calcium stearate, and talc. Suitable carriers for oral dosage forms include but are not limited to magnesium carbonate, magnesium stearate, talc, lactose, pectin, dextrin, starch, methylcellulose, sodium carboxymethyl cellulose, and the like. Techniques used to prepare oral formulations are the conventional mixing, granulation and compression or capsules filling. The compounds of the present invention may be also formulated for parenteral administration with suitable carriers including aqueous vehicles solutions (i.e. : saline, dextrose) or and/or oily emulsions.

The invention will be now further detailed with reference to the experimental part.

Experimental part Example 1

1.A. Preparation of 3-CD-PMDA (Pyromellitic dianhydride), nanosponqe 1.A.

12.26 g of anhydrous Linecaps (KLEPTOSE® Linecaps (LC provided by ROQUETTE) was dissolved in 50 ml_ of dimethyl sulfoxide in a 100 ml_ round bottom flask. Subsequently, 6.3 mL of triethylamine and 9.46 g of pyromellitic dianhydride were introduced. The solution was stirred at room temperature until gelation. 24 h later, the rigid gel was broken with a spatula, ground in a mortar and cleaned with deionized water through Buchner filtration. After a final rinse with acetone, the nanosponge was dried at room temperature.

1.B. Preparation of LC-citric, nanosponqe 1.B

An aqueous solution of monomers was prepared by dissolving 20.00 g of Linecaps (KLEPTOSE® Linecaps (LC provided by ROQUETTE), 1 .87 g of sodium hypophosphite monohydrate and 13.54 g of citric acid in 100 mL of deionized water, in a 250 mL beaker. Afterwards, the solution was poured in a 20 cm-diameter crystallizing dish and heated in an oven for 1 h at 140 °C and 4 h at 100 °C, under low pressure (~20 mbar). At the end of the reaction, a rigid sponge-like polymer was obtained. The polymer was soaked in deionized water to soften and then it was stirred. After a few minutes, the stirring was stopped and the polymer left to sediment. The supernatant was carefully poured away, in order to remove the soluble and colloidal fractions of the polymer, and replaced with fresh deionized water. This cleaning cycle was repeated five-six times, until a clear and colourless supernatant was observed. Finally, the NS was filtered in a Buchner funnel, rinsed with acetone and left to dry at room temperature.

1.C. Preparation of LC-STMP (sodium trimetaphosphate (STMP). nanosponqe 1.C 4.000 g of Linecaps (KLEPTOSE® Linecaps (LC provided by ROQUETTE) was dissolved in 18 mL of a 1 .5 M NaOH solution in a 40 mL vial. Then, 2,156 g of sodium trimetaphosphate was added. After a few minutes under stirring, a rigid polymer gel was formed. The gel was removed from the vial and ground in a mortar. Finally, the gel was washed several times with deionized water in a Buchner funnel and rinsed with acetone. After drying at room temperature, a white powder was collected.

Example 2

A) Preparation of the blank nanosponqe aqueous nanosuspension

Three types of nanosponges prepared as in example 1. i.e b-CD-PMDA (Pyromellitic dianhydride), LC-citric and LC-STMP (sodium trimetaphosphate (STMP) were used for loading apomorphine and hence prepare the final formulation. Firstly, a nanosuspension of blank each nanosponge (NS) prepared in example 1 was prepared by using a top-down method. For this purpose, the NS coarse powder was suspended in saline solution (NaCI 0.9% w/v) at the concentration of 10 mg/ml. The sample was homogenized using a high shear homogenizer (Ultraturrax®, IKA, Konigswinter, Germany) for 10 min at 24,000 rpm. Then, a high pressure homogenization (HPH) step was performed using an EmulsiFlex C5 instrument (Avestin, Mannheim, Germany) for 90 min at a back-pressure of 500 bar, to further reduce the size of the NS and obtain an homogeneous size distribution.

The blank NS aqueous nanosuspension was purified by dialysis (Spectra/Por cellulose membrane, cut-off 12,000 Da; Spectrum Laboratories, Rancho Dominguez, CA, USA) to eliminate potential synthesis residues.

B) Preparation of the at least one apomorphine-loaded formulation, i.e. an apomorphine-loaded nanosponqe

Three types of blank nanosponges were used for loading apomorphine and hence prepare the final formulation.

A blank aqueous nanosuspension for each nanosponges (b-CD-PMDA,, LC-citric or LC-STMP) was used for the apomorphine loading. After the addition of an antioxidant (i.e. ascorbic acid 0.1 % w/v) and EDTA 0.05 % to the nanosponge nanosuspension, an amount of apomorphine (generally 2 mg/ mL) was added to each one. The systems were stirred overnight in the dark. Subsequently, the nanosuspension was purified by dialysis to eliminate the apomorphine not incorporated.

In order to obtain apomorphine-loaded NS as a powder, the sample was freeze- dried using a Modulyo freeze-drier (Edwards, Crawley, UK).

Example 3

Physical-chemical characterization of the pharmaceutical formulation i.e. apomorphine loaded nanosponqes Blank and apomorphine-loaded nanosponges were in vitro characterized by determining their physico-chemical parameters. Average diameter, polydispersity index and zeta potential were measured by Dynamic Light Scattering (DLS) using a 90 Plus particle sizer (Brookhaven Instruments Corporation, USA). The measurements were carried out at a fixed scattering angle of 90° and at 25°C. For the analysis, the samples were diluted in filtered water (1 :30 v/v). For Zeta potential determination the diluted samples were placed in the electrophoretic cells where an electric field of approximately 15 V/cm was applied.

The average diameter, polydispersity index and zeta potential value of the apomorphine-loaded nanosponges are reported in Table 1. Table 1 Physico-chemical characteristics of apomorphine-loaded nanosponges formulations

All the apomorphine-loaded nanosponges showed sizes lower than 600 nm and a negative zeta potenzial, with a value high enough to assure the physical stability of the nanosponge aqueous nanosuspensions.

Apomorphine quantitative determination

The quantitative determination of apomorphine was carried out by spectrophotometric analysis using an UV-Vis spectrophotometer (DU730 Beckman Coulter).

The concentration of apomorphine was calculated using the external standard method from a calibration curve. A stock standard solution was prepared dissolving a weighted amount of apomorphine in filtered water added of 0.1%w/v sodium metabisulfite. Then, this solution was diluted with the same solvent providing a series of standard solutions over the concentration range of 1 to 15 pg/mL. The absorbance of each standard solution was measured at 272 nm. The calibration curve was obtained by plotting the absorbance versus the corresponding drug concentration and reported in Figure 1. The calibration curve was linear over the concentration range of 1-15 pg/mL, with a regression coefficient of 0.999.

Table 2. Apomorphine calibration curve

In vitro stability studies

The apomorphine-loaded nanosponges prepared in example 2 were stored at 4 °C and their physico-chemical stability was evaluated by measuring the apomorphine concentration over time.

To determine the apomorphine concentration in the nanosponges, the samples were diluted with filtered water (1:100 v/v), sonicated for 15 minutes and filtered by 0.22 micron filter to separate the apomorphine from the nanosponges. The filtrate was analyzed by spectrophotometric analysis to measure the apomorphine concentration. The results are reported in Figure 2. The apomorphine concentration present in the apomorphine-loaded nanosponges did not change for 6 months.

Example 4

Determination of loading capacity and encapsulation efficiency A weighted amount of each freeze-dried apomorphine-loaded nanosponge as prepared in example 2 and characterized in example 3 was suspended in filtered water and sonicated for 15 minutes. After centrifugation (20000 rpm, 10 min), the supernatant was filtered by 0.22 micron filter and then analyzed by spectrophotometer to quantify the amount of apomorphine loaded in the NS.

The loading capacity of each apomorphine-loaded nanosponge was calculated using the formula:

Loading capacity (%) = [amount of apomorphine loaded/weight of apomorphine- loaded NS] X 100

The encapsulation efficiency was calculated as follows:

Encapsulation efficiency (%) = [amount of apomorphine loaded/total amount of apomorphine

The loading capability and encapsulation efficiency of apomorphine was determined on freeze-dried samples. The drug encapsulation efficiency was higher than 90 % and the loading capability ranged from 2 % to 20%.

Example 5

In vitro drug release study

The in vitro release studies were carried out using multi-compartment rotating cells. The donor phase, consisting of 1 ml of each apomorphine-loaded nanosponge as prepared in example 1 , was separated from the receiving phase by a dialysis membrane (Spectra/Por cellulose membrane, cut-off 12,000 Da). The receiving phase was phosphate buffered solution (PBS) added of 0.1 % w/v sodium metabisulfite. The in vitro release was evaluated using PBS at three different pH values, one simulating gastric fluid (pH = 1.2) and another intestinal fluid (pH = 6.8) and at pH = 4.0. At fixed times the receiving phase was completely withdrawn and replaced with fresh receiving medium. The withdrawn samples for were analysed using an UV-Vis spectrophotometer to determine the apomorphine concentration. The results are reported in Figure 3 and Figure 4. Apomorphine delivery from all the nanosponges showed a constant and extended release kinetics.

Example 6

In vivo oral administration of apomorphine in nanosponqes To investigate the oral absorption of apomorphine encapsulated in the nanocarrier, an apomorphine-loaded PMDA nanosponge aqueous suspension at the drug concentration of 1 mg/mL was administered directly into the duodenal lumen of fed rats by a surgical implanted duodenal cannula. Blood samples were collected through a surgical implanted cannula inserted in the Jugular vein into heparinized tubes at designed time until 24 hours after the formulation administration. An apomorphine solution was administered into the duodenum of rats as controls. All plasma samples were analyzed using the tuned HPLC method with a fluorometric detector.

Figure 5 reports the apomorphine plasma concentration over time after the administration of apomorphine solution and apomorphine loaded in nanosponges. The results showed that apomorphine in nanosponges showed an increase in stability and oral bioavailability.

Claims

1. An extended and controlled release formulation comprising at least one apomorphine loaded nanosponge of:

- apomorphine or a pharmaceutically salt thereof, and

2. The extended and controlled release formulation according to claim 1 , wherein the pharmaceutical formulation comprises a cross-linked polymer of i) a dextrin, that is a cyclodextrin selected from a-cyclodextrin, b-cyclodextrin and g-cyclodextrins.

3. The extended and controlled release formulation according to claim 2, wherein the dextrin i) is b-cyclodextrin.

4. The extended and controlled release formulation according to claim 1 , wherein the pharmaceutical formulation comprises a cross-linked polymer of ii) a maltodextrin deriving from leguminous starch.

5. The extended and controlled release formulation according to claim 4, wherein the leguminous starch derives from a plant is chosen from the group formed by the pea, bean, broad bean, horse bean and their mixtures, more preferably the leguminous plant is a variety of pea or horse bean.

6. The extended and controlled release formulation according to claim 4, wherein the leguminous starch has an amylose content in the range from 30% to 40%, preferably from 35% to 40%, more preferably from 35% to 38%, these percentages being expressed as dry weight relative to the dry weight of starch.

7. The extended and controlled release formulation according to anyone of claims 1-6, wherein the crosslinking compound is a dianhydride, preferably pyromellitic dianhydride.

8. The extended and controlled release formulation according to claim 1 wherein the least one apomorphine loaded nanosponge is selected from b-CD-PMDA (Pyromellitic dianhydride) nanosponge, Linecaps- citric acid nanosponge and Linecaps-STMP (sodium trimetaphosphate (STMP) nanosponge.

9. The extended and controlled release formulation according to claim 8, wherein b-CD-PMDA (Pyromellitic dianhydride) has an average diameter from 150 to 600 nm; a polydispersity index from 0.10 to 0.35; and a Zeta potential from - 10 to - 30 mV.

10. The extended and controlled release formulation according to claim 8, wherein apomorphine-Linecaps-citric acid has an average diameter from 200 nm to 700 nm; a polydispersity index from 0.1 to 0.4; and a Zeta potential from - 10 mV to - 30 mV.

11. The extended and controlled release formulation according to claim 8, wherein apomorphine-Linecaps-STMP (sodium trimetaphosphate (STMP) has an average diameter from 100 nm to 500 nm; a polydispersity index from 0.1 to 0.3; and a Zeta potential from - 10 mV to -40 mV.

12. The extended and controlled release formulation according to anyone of claims 1-11 , wherein the loading capacity ranged from 2% to 20% and the encapsulation efficiency ranged from 90 % to 99 % for all apomorphine loaded nanosponges.

13. A method for improving the bioavailability of apomorphine by avoiding its oxidative degradation by using the pharmaceutical formulation according to anyone of claims 1-12.

14. A pharmaceutical formulation according to anyone of claims 1-12 for use as a medicament.

15. A pharmaceutical formulation according to anyone of claims 1-12 for use in the treatment of Parkinson’s disease.