CN101708164A - Rivastigmine slow-release microspheres and preparation method thereof - Google Patents

Abstract

The invention discloses a PLGA/PLA injection slow-release microsphere encapsulating tartaric acid/rivastigmine bitartrate and a preparation method thereof. The slow-release microsphere is mainly composed of tartaric acid/rivastigmine bitartrate and biodegradable polymer The medicinal material is composed of lactic acid-glycolic acid copolymer PLGA and polylactic acid PLA, which can be used by W ₁ /O/W ₂ double emulsification solvent evaporation method, O/W emulsification solvent evaporation method, O ₁ /O ₂ drying method in emulsion and Prepared by spray-drying method, the particle size of the microspheres is less than 100 microns, the drug loading capacity is high, there is no obvious burst release effect, and the release can be sustained for one week, one month or three months. The sustained-release microspheres are used for the treatment of Alzheimer's disease, Senile diseases such as Parkinson's disease can prolong the drug action time, reduce the frequency of medication, and greatly improve the patient's compliance with medication.

Description

A kind of rivastigmine sustained-release microspheres and preparation method thereof

technical field

The invention belongs to the technical field of pharmacy, and in particular relates to a slow-release microsphere for tartrate/rivastigmine bitartrate PLGA/PLA injection and a preparation method thereof.

Background technique

Alzheimer's disease (AD), also known as senile dementia, is a type of senile central nervous system degenerative disease, and its exact etiology is not yet fully understood. At present, the hypothesis of cholinergic nerve damage is widely accepted. It is generally believed that the cognitive deficits in patients with Alzheimer's disease are caused by the dysfunction of cholinergic nerve conduction in the cerebral cortex and forebrain base. Through cholinergic nerve conduction to improve symptoms. Acetylcholinesterase inhibitors restore the normal level of acetylcholine and increase the excitability of cholinergic neurons by inhibiting the activity of acetylcholinesterase, which has been proved to be effective both theoretically and clinically.

Tartaric acid/rivastigmine bitartrate (trade name Exelon, Chinese Aisi can, developed by Novartis), its chemical name is (S)-N, N-ethylmethyl-carbamic acid-3-[1-(di Methylamino)ethyl]phenyl ester. Rivastigmine tartrate/bitartrate is a long-acting reversible non-competitive carbamate acetylcholinesterase inhibitor selectively acting on the brain, and also a butyrylcholinesterase inhibitor, belonging to the third generation Drugs that improve the function of the cholinergic nervous system. Its effect on the central nervous system is much stronger than that on the peripheral nervous system, and clinical application will not cause liver toxicity. In 2000, it was approved by the US FDA for the treatment of moderate and severe Alzheimer's disease, and in 2006 it was approved for the treatment of mild and moderate dementia related to Parkinson's disease. Clinical dosage forms include capsules (each tablet contains 1.5, 3, 4.5 and 6 mg), oral liquid preparations and transdermal patches. Capsules and oral liquid formulations are administered twice daily, and transdermal patches are administered once daily. These conventional preparations, in addition to frequent administration and inconvenient treatment, the peak-valley phenomenon of drug concentration is also a problem. In comparison, sustained-release preparations, especially for one month or even three months, have more practical significance in terms of practical therapeutic applications.

PLGA/PLA is a medical polymer material with good biocompatibility, biodegradability, good safety, and excellent physical and chemical properties. This material has been approved by the US FDA for sustained-release drug carriers and other human implanted devices . After PLGA/PLA enters the human body, it first degrades into lactic acid and glycolic acid in the human body, and then further degrades into carbon dioxide and water to be excreted from the body, which is harmless to the human body. The degradation rate of PLGA in vivo can be regulated by the content and order of glycolic acid in its molecule.

At present, no research on rivastigmine tartrate/hydrotartrate preparations has been found, so developing a long-acting sustained-release preparation for the treatment of senile diseases such as Alzheimer's disease and Parkinson's disease has great clinical significance and applicable value. The technical problem to be solved by the present invention is to provide a kind of preparation process that is easy to wrap tartaric acid/rivastigmine bitartrate in biodegradable lactic acid-glycolic acid copolymer (PLGA) or polylactic acid (PLA), and prepare it for injection The method of sustained-release microspheres capable of slow and sustained release for 1 week, one month or even three months, the tartaric acid/rivastigmine bitartrate sustained-release microsphere preparation prepared by this method has high drug loading, high encapsulation efficiency, no With the characteristics of obvious burst release and sustained slow release, it can be used to treat moderate to severe Alzheimer's disease and mild to moderate dementia related to Parkinson's disease.

Contents of the invention

The invention discloses a slow-release microsphere for tartaric acid/rivastigmine bitartrate PLGA/PLA injection, which is characterized in that it is composed of tartaric acid/rivastigmine bitartrate and biodegradable medicinal The polymer auxiliary material is composed, and its parts by weight are:

Tartrate/Rivastigmine Bitartrate 0.28%～9.11%

Polymer excipients 90.89%～99.72%

Its preparation method can be prepared by W ₁ /O/W ₂ double emulsification solvent evaporation method, O/W emulsification solvent evaporation method, O ₁ /O ₂ emulsion drying method and spray drying method, preferably O ₁ /O ₂ emulsion Medium drying method.

The tartaric acid/rivastigmine bitartrate sustained-release microspheres of the present invention, wherein the active ingredient is rivastigmine, the common English name is Rivastigmine, and the Chinese chemical name is (S)-N, N-ethylmethyl-carbamic acid-3- [1-(Dimethylamino) ethyl] phenyl ester, its structural formula is as shown in the figure below:

Acids that can form salts with it include tartaric acid and bitartrate, which form rivastigmine tartrate and rivastigmine bitartrate respectively. Biodegradable polymer pharmaceutical excipients PLGA/PLA, PLGA has a molecular weight of 5,000 to 50,000 Daltons, of which lactic acid The ratio of PLA to glycolic acid is 90:10 to 50:50, the molecular weight of PLA is 6,000-100,000 Daltons, it can be either carboxyl terminal or alkyl terminal, and the polymer excipients that make up the slow-release microspheres are the above-mentioned One or a mixture of two or more.

The tartrate/rivastigmine bitartrate PLGA/PLA sustained-release microspheres for injection of the present invention comprises the following steps:

(1) Dissolve PLGA/PLA in a single or multi-component organic solvent with a certain polarity, add tartaric acid/rivastigmine bitartrate, and stir to dissolve it to form a clear dispersed phase;

(2) The dispersed phase is mixed with the continuous phase composed of an oily inert medium containing a certain concentration of emulsifier, wherein the organic solvent in the dispersed phase is incompatible with the oily inert medium of the continuous phase, and is emulsified for a period of time under rapid stirring;

(3) After the emulsification is completed, the organic solvent is gradually volatilized, and the drug-loaded microspheres are precipitated;

(4) The obtained microspheres are collected by filtration, the oily inert medium adsorbed on the surface of the microspheres is washed off successively with a non-polar solvent, and the free drug adsorbed on the surface of the microspheres is washed off with a strong polar solvent, and obtained by conventional freeze-drying. The organic solvent of the phase is a single solvent of chloroform, dichloromethane, ethyl acetate, methyl acetate, dioxane, ether, acetone, tetrahydrofuran, acetonitrile or multiple solvents mixed in a certain proportion; the oily inert medium of the continuous phase is Mineral oil composed of liquid paraffin or simethicone, vegetable oil composed of tea oil, peanut oil or soybean oil, and polyol composed of glycerin, wherein the volume ratio of the dispersed phase to the continuous phase is 1:40 to 1:10.

Wherein the emulsifier used in the step (2) is a nonionic surfactant with an HLB value ranging from 1.8 to 12.4, preferably Span 80 (Span80), and its concentration in the continuous phase is 0.05% to 2%.

Wherein in the step (4), the solvent used to wash away the oily inert medium adsorbed on the surface of the microspheres is one or both of normal hexane, hexane, and sherwood oil, and the strong polar solvent is one of water, methanol, and ethanol one or two.

Four specific preparation methods of the sustained-release microsphere preparation of the present invention are as follows:

1. W ₁ /O/W ₂ double emulsification-solvent evaporation method:

(1) An appropriate amount of tartaric acid/rivastigmine bitartrate and additives are dissolved in a certain amount of water to form an internal water phase. Among them, the concentration of tartrate/rivastigmine bitartrate is 50-200 μg/mL, and the types of additives are gelatin, poloxamer 188, poloxamer 407, polyethylene glycol 1000, polyethylene glycol 6000, polyethylene glycol Diol 10000, polyethylene glycol 20000;

(2) Dissolve a certain amount of PLGA or PLA in the organic solvent dichloromethane or ethyl acetate at a concentration of 10mg/mL-100mg/mL to form an oil phase;

(3) adding the inner water phase to the oil phase, ultrasonic emulsification to form colostrum;

(4) Colostrum is quickly added dropwise to 0.1%～2% polyvinyl alcohol (PVA) aqueous solution, and this solution also can also have 0～5% sodium chloride or 0～5% sucrose, and magnetic stirring is fully homogenized, Stir at a speed of 3,500-10,000 rpm, continue stirring at a low speed at room temperature for 6 hours to volatilize the organic solvent, and stir at a speed of 300-600 rpm to obtain slow-release microspheres, wash, collect, and freeze-dry.

2. O/W emulsification-solvent evaporation method

(1) Dissolve an appropriate amount of tartaric acid/rivastigmine bitartrate and PLGA or PLA in a mixed solvent composed of a weak polar organic solvent and a strong polar organic solvent, wherein the weak polar organic solvent includes dichloromethane, ethyl acetate , methyl acetate, strong polar organic solvents including methanol, acetonitrile, propylene glycol, dimethyl sulfoxide. The concentration of tartrate/rivastigmine bitartrate in the organic phase is 50-200 μg/mL, and the concentration of PLGA or PLA is 10 mg/mL-100 mg/mL;

(2) Add the organic phase to an aqueous solution containing 0.1% to 2% polyvinyl alcohol (PVA), and the solution may also have 0 to 5% sodium chloride or 0 to 5% sucrose, fully homogenized by magnetic stirring, and stir The speed is 3,500-10,000 rpm, and the organic solvent is continuously stirred at a low speed at room temperature for 6 hours, and the stirring speed is 300-600 rpm, and the slow-release microspheres are obtained, washed, collected, and freeze-dried.

3. Drying method in O ₁ /O ₂ emulsion

(1) Dissolve PLGA or PLA in a single or multi-component organic solvent with a certain polarity, add tartaric acid/rivastigmine bitartrate, stir to dissolve and form a clear dispersed phase; the organic solvent of the dispersed phase is chloroform, dichloro Methane, ethyl acetate, methyl acetate, dioxane, diethyl ether, acetone, tetrahydrofuran, acetonitrile single solvent or multiple solvents mixed in a certain proportion; the concentration of PLGA or PLA is 10mg/mL～100mg/mL, tartaric acid/ The concentration of rivastigmine bitartrate is 1mg/mL～10mg/mL.

(2) Mix the dispersed phase with a continuous phase composed of an oily inert medium containing a certain concentration of emulsifier, wherein the organic solvent in the dispersed phase is incompatible with the oily inert medium of the continuous phase, and emulsify for a period of time under rapid stirring. Among them, the oily inert medium of the continuous phase is mineral oil composed of liquid paraffin or simethicone; vegetable oil composed of tea oil, peanut oil or soybean oil, and polyol composed of glycerin; the emulsifier is a nonionic surfactant. Disk 80 (Span80), its concentration in the continuous phase is 0.05%-2%; the volume ratio of the dispersed phase to the continuous phase is 1:40-1:10; the stirring speed during emulsification is 500-2,000 rpm;

(3) After the emulsification is completed, the organic solvent is stirred at a low speed to gradually volatilize, and the drug-loaded microspheres are precipitated. Wherein the stirring speed is 300～600 rpm;

(4) The obtained microspheres are collected by filtration, and the oily inert medium adsorbed on the surface of the microspheres is washed away successively with non-polar solvent n-hexane, and the free drug adsorbed on the surface of the microspheres is washed away with water, and conventional freeze-drying is obtained.

4. Spray drying method

The tartaric acid/rivastigmine bitartrate and PLGA/PLA are dissolved in a certain polar organic solvent, stirred evenly, and spray-dried to obtain the product. The organic solvent used includes one or two or more mixed solvents of dichloromethane, ethyl acetate, glacial acetic acid, and methyl acetate. Wherein, the concentration of rivastigmine tartrate/hydrotartrate is 1-10 mg/mL, and the concentration of PLGA or PLA is 10-100 mg/mL. During spray drying, the inlet temperature is 50°C, the outlet temperature is 35°C, the flow rate is 30%, and the spray pressure is 50%.

The biodegradable polymer pharmaceutical excipient PLGA/PLA used in the present invention has a molecular weight of 5,000-50,000 Daltons, wherein the ratio of lactic acid to glycolic acid is 90:10 to 50:50, and the molecular weight of PLA is 6,000-100,000 Daltons, either carboxy-terminated or alkyl-terminated. The polymer excipients constituting the sustained-release microspheres are one or a mixture of two or more of the above.

The sustained-release microspheres prepared by the invention have a particle diameter of 1-100 microns.

The slow-release microspheres prepared by the invention have a smooth and round surface without adhesion.

In the slow-release microspheres prepared by the present invention, tartaric acid/rivastigmine bitartrate is distributed in the microspheres in a molecular or amorphous state.

The sustained-release microspheres prepared by the present invention can be released slowly and sustainably for one week or one month according to in vitro release experiments, and no obvious burst release effect has been observed.

The present invention has successfully prepared sustained-release microspheres for injection coated with tartaric acid/rivastigmine bitartrate, which have the characteristics of high drug loading, high encapsulation rate, no obvious burst release, and sustained slow release, which can be used for the treatment of moderate and severe Alzheimer's disease and mild to moderate dementia associated with Parkinson's disease.

Detailed ways

Example 1: W ₁ /O/W ₂ double emulsification-solvent evaporation method to prepare rivastigmine tartrate sustained-release microspheres

Dissolve 25mg rivastigmine tartrate and 50mg poloxamer 188 in 0.2mL water as the inner aqueous phase; dissolve 100mg PLGA (RG502H, PLA:PGA=50:50, Mw=20000) in 2.0mL ethyl acetate , forming the oil phase. Add the inner water phase to the oil phase, ultrasonically emulsify with the probe, work at a frequency of 200 watts, work for 1 second, and rest for 1 second to obtain W ₁ /O colostrum. Quickly pour the colostrum into 40mL of rapidly stirred 0.1% PVA aqueous solution (adjust the pH to 9.0 with glycine-sodium hydroxide, which contains 1% sodium chloride), stir at 7,000 rpm, and emulsify for 2 minutes at room temperature Continue stirring at a speed of 500 rpm for 6 hours to evaporate the organic solvent, collect the solidified microspheres by centrifugation, wash with distilled water three times, and freeze-dry to obtain the microspheres.

Embodiment 2: O/W emulsification-solvent volatilization method prepares rivastigmine tartrate sustained-release microspheres

Dissolve 25mg rivastigmine tartrate and 100mg PLGA (RG502H, PLA:PGA=50:50, Mw=20000) in a mixed solvent consisting of 2mL ethyl acetate and 0.2mL propylene glycol to form an oil phase. Pour the oil phase quickly into 40mL of 0.1% PVA aqueous solution (adjust pH 9.0 with glycine-sodium hydroxide, which contains 1% sodium chloride), stir at 7,000 rpm, and emulsify for 2 minutes at room temperature. Continue stirring at a speed of 500 rpm for 6 hours to evaporate the organic solvent, collect the solidified microspheres by centrifugation, wash with distilled water three times, and freeze-dry to obtain the microspheres.

Example 3: Preparation of rivastigmine tartrate sustained-release microspheres by O ₁ /O ₂ emulsification-drying method in liquid

Dissolve 20mg rivastigmine tartrate and 200mg PLGA (RG502H, PLA:PGA=50:50, Mw=20000) in 2mL of a mixed solvent composed of dichloromethane and acetonitrile (volume ratio 3:2), and ultrasonically vibrate to make it Dissolve to form the internal oil phase; inject the internal oil phase into 40mL liquid paraffin containing 0.2% Span 80, stir at 800 rpm for 15 minutes to emulsify, continue stirring at 500 rpm for 6 hours at room temperature to evaporate the organic solvent, filter , followed by washing the microspheres with n-hexane and water, redissolving in a small amount of water, and freeze-drying to obtain the microspheres.

Example 4: Preparation of rivastigmine tartrate sustained-release microspheres by O ₁ /O ₂ emulsification-drying method in liquid

Dissolve 20 mg rivastigmine tartrate, 50 mg PLGA (RG752H PLA:PGA=75:25, Mw=20000) and 150 mg PLA (R202S, Mw=20000) in 2 mL of dichloromethane and acetonitrile (volume ratio 3:2) In the mixed solvent, ultrasonically oscillate to dissolve and form the internal oil phase; inject the internal oil phase into 40mL liquid paraffin containing 0.2% Span 80, stir at 800 rpm for 15 minutes to emulsify, and continue at room temperature at 500 rpm Stir for 6 hours to evaporate the organic solvent, filter, wash the microspheres with n-hexane and water successively, redissolve in a small amount of water, and freeze-dry to obtain the microspheres.

Embodiment 5: Preparation of rivastigmine tartrate sustained-release microspheres by spray drying method

Dissolve 30mg of rivastigmine tartrate and 300mg of PLGA (RG752H PLA:PGA=75:25, Mw=20000) in 15mL of glacial acetic acid, ultrasonically oscillate to dissolve completely, and spray dry under the following conditions: inlet temperature 50°C, outlet The temperature is 35°C, the flow rate is 30%, and the spray pressure is 50%, to obtain microspheres.

Embodiment 6: Determination of drug loading of rivastigmine tartrate sustained-release microspheres

Accurately weigh a certain amount of microspheres (less than 10mg), add 0.5mL of dichloromethane, ultrasonically oscillate to dissolve completely, then add 5mL of 0.1M hydrochloric acid, vortex and mix well, centrifuge at 4000 rpm for 10 minutes, remove the supernatant After the solution was filtered, the concentration of rivastigmine tartrate was determined by HPLC, and the drug loading capacity of the microspheres was calculated.

Example 7: In vitro drug release experiment of rivastigmine tartrate sustained-release microspheres

Accurately weigh a certain amount of microspheres (less than 50 mg), add 8 mL of pH 7.4 phosphate buffer (containing 0.02% Tween 80 and 0.02% sodium azide) as a release medium, and place at 37 ° C, 50 rpm at a constant temperature Shake on a shaker. On days 0.5, 1, 3, 5, 7, 14, 21, and 28, 6 mL of the supernatant was taken, and after filtration, the concentration of rivastigmine tartrate was determined by HPLC; at the same time, the same volume of fresh release medium was added.

Description of drawings

The scanning electron microscope picture of the rivastigmine tartrate sustained-release microspheres prepared by accompanying drawing 1 embodiment 3

The X-ray diffraction pattern of the rivastigmine tartrate sustained-release microspheres prepared in accompanying drawing 2 embodiment 3

Note: (1) is PLGA; (2) is rivastigmine tartrate API; (3) is the physical mixture of PLGA and rivastigmine tartrate API; (4) rivastigmine tartrate sustained-release microspheres

The in vitro release curve of the rivastigmine tartrate slow-release microspheres prepared by accompanying drawing 3 embodiment 3

The in vitro release curve of the rivastigmine tartrate slow-release microspheres prepared by accompanying drawing 4 embodiment 4

Claims (10)

1. tartaric acid/rivastigmine-hydrogentartrate PLGA/PLA slow release microphere for injection, it is characterized in that by tartaric acid/rivastigmine-hydrogentartrate and molecular weight ranges 5,000～50, the biodegradable medicinal high polymer adjuvant between 000 is formed, and its parts by weight are:

Tartaric acid/rivastigmine-hydrogentartrate 0.28%～9.11%

High polymer adjuvant 90.89%～99.72%

2. sustained-release micro-spheres according to claim 1 is characterized in that adopting W ₁/ O/W ₂Emulsion solvent evaporation method, O/W emulsion-solvent evaporation method, O ₁/ O ₂Emulsifying intra-liquid desiccation method and spray drying method for preparation, preferred O ₁/ O ₂The emulsifying intra-liquid desiccation method.

3. sustained-release micro-spheres according to claim 1, it is characterized in that active component is a Rivastigmine, general English is called Rivastigmine, the chinesization formal name used at school is (S)-N, N-ethyl-methyl-carbamic acid-3-[1-(dimethylamino) ethyl] phenyl ester, can tartaric acid and liquor epinephrinae bitartratis ophthalmicus be arranged acid salifiable, form tartaric acid Rivastigmine and rivastigmine-hydrogentartrate respectively with it.

4. rivastigmine slow-release microspheres according to claim 1, it is characterized in that Biodegradable high-molecular pharmaceutic adjuvant PLGA/PLA, the molecular weight of PLGA is 5,000～50,000 dalton, wherein the ratio of lactic acid and hydroxyacetic acid is 90: 10 to 50: 50, and the molecular weight of PLA is 6,000～100,000 dalton, both can be carboxyl terminal, also can be the alkyl end, and the high polymer adjuvant of forming sustained-release micro-spheres is one or both and the two or more mixture in above-mentioned.

5. O according to claim 4 ₁/ O ₂Emulsifying-intra-liquid desiccation method, this method comprises the following steps:

(1) PLGA/PLA has been dissolved in certain polar single or polynary organic solvent, has added tartaric acid/rivastigmine-hydrogentartrate, stirred and make it the clarifying decentralized photo of dissolving formation;

(2) continuous phase that decentralized photo and the oiliness inert media that contains certain density emulsifying agent are formed is mixed, and wherein the organic solvent in the decentralized photo does not dissolve each other mutually with the oiliness inert media of continuous phase, emulsifying a period of time under stirring fast;

(3) emulsifying is volatilized organic solvent after finishing gradually, separates out medicine carrying microballoons;

(4) filter the microsphere that collection obtains, with the oiliness inert media of non-polar solven flush away microsphere surface absorption, with the free drug of intensive polar solvent flush away microsphere surface absorption, normal freeze-drying promptly successively.

6. method according to claim 5, the organic solvent that it is characterized in that decentralized photo are the single solvent of chloroform, dichloromethane, ethyl acetate, methyl acetate, dioxane, ether, acetone, oxolane, acetonitrile or blended by a certain percentage multicomponent solvent; The oiliness inert media of continuous phase is the mineral oil that liquid paraffin or simethicone etc. are formed, the polyhydric alcohol that vegetable oil that Oleum Camelliae, Oleum Arachidis hypogaeae semen or soybean oil are formed and glycerol are formed, and wherein the volume ratio of decentralized photo and continuous phase is 1: 40～1: 10.

7. method according to claim 5, wherein the used emulsifying agent of step (2) is the nonionic surfactant of HLB value scope between 1.8～12.4, preferred sorbester p17 (Span80), its concentration in continuous phase is 0.05%～2%.

8. method according to claim 5, the solvent that it is characterized in that being used in the step (4) the oiliness inert media of flush away microsphere surface absorption is one or both of normal hexane, hexane, petroleum ether, and intensive polar solvent is one or both in water, methanol, the ethanol.

9. sustained-release micro-spheres according to claim 1 is characterized in that microspherulite diameter is 1～100 micron.

10. the slow release microphere for injection of the described tartaric acid/rivastigmine-hydrogentartrate of claim 1 is characterized in that being used for the treatment of Senile disease as Alzheimer and parkinson disease etc. as durative action preparation.

Images