Asenapine maleate oral adhesive film preparation as well as preparation method and application thereof

Abstract

The invention discloses an asenapine maleate oral adhesion film preparation as well as a preparation method and application thereof, belongs to the field of pharmaceutical preparations, and particularly relates to an asenapine maleate self-nanoemulsion oral adhesion film and an asenapine maleate nanocrystal oral adhesion film preparation. The self-nanoemulsion can improve the solubility of asenapine maleate, the lower surface tension of the self-nanoemulsion is beneficial to penetrating through a mucous membrane hydration layer and enhancing mucous membrane absorption, and the nanocrystal can improve the solubility and dissolution rate of API, increase the drug concentration gradient near the oral mucosa and promote diffusion and oral absorption of drugs. The oral cavity adhesion film can adhere to the sublingual part and rapidly release the medicine, the medicine is absorbed by rich submucosal blood vessels and directly enters systemic circulation, metabolism of the gastrointestinal tract and the liver is avoided, and then oral bioavailability is enhanced.

Description

Technical Field

[0001] The invention belongs to the field of pharmaceutical preparations, and in particular relates to a preparation method and application of an asenapine maleate self-nanoemulsion oral adhesive film and an asenapine maleate nanocrystal oral adhesive film preparation. Background Art

[0002] Schizophrenia is a chronic mental disorder characterized by abnormal behavior and confusion with reality. Patients will experience positive symptoms characterized by fantasy, negative symptoms characterized by weakened emotional expression and lack of motivation, and cognitive defects characterized by impaired learning and memory. Patients are unable to integrate into social and family life, distort reality, and even have antisocial tendencies. The common problem of poor compliance among patients is the key to the high relapse rate, so the disease is intermittent, the long-term treatment effect is poor, and the symptoms cannot be completely relieved. In severe cases, there are violent tendencies such as suicide and disability. Not only are patients deeply troubled, but also a heavy burden on families and society. It is estimated that schizophrenia is a major part of the burden of mental illness, accounting for 15% of total health care expenditures. This disease usually begins in adolescence, reducing life expectancy by 10 years. The early onset, long course, and high relapse rate make schizophrenia one of the most burdensome and costly diseases in the world.

[0003] At present, the main treatment for schizophrenia is still drug therapy, mostly using atypical antipsychotics such as olanzapine and risperidone, but these drugs have serious adverse reactions when used for a long time. As the latest atypical antipsychotic drug, asenapine maleate has a wider range of indications, better tolerance, lower toxicity and side effects compared with olanzapine and risperidone, and can be used for emergency treatment of adult patients, with broad application prospects and clinical efficacy.

[0004] Asenapine Maleate (ASM), also known as asenapine, has a structural formula of (3aRS, 12bRS)-5-chloro-2,3,3a,12b-tetrahydro-2-methyl-1H-dibenzo[2,3:6,7]oxa [4,5-c]pyrrole is an atypical antipsychotic drug belonging to the dibenzoxazolidine pyrrole class. It is a white powder with a molecular formula of C 17 H 16ClNO·C4H4O4, the structural formula is shown in formula (I). This drug belongs to BCS class II drugs, is poorly soluble in water, and is easily soluble in ethanol, methanol, acetone, etc., with a logP of 4.9 and a pKa value of 8.6 (25°C). ASM is mainly directly glucuronidated by uridine diphosphate glucuronosyltransferase 1A4 (UGT1A4) and cytochrome P450 1A2 (CYP1A2). Nearly 38 metabolites have been identified, but none of them show clinically relevant activity, and none of them can cross the blood-brain barrier. ASM interacts with a wide range of receptors in the body, but its exact mechanism of action is still unclear. In schizophrenia, it shows effects on dopamine D2 and 5-HT 2A receptor antagonism, and at the same time, it has an antagonistic effect on D1, D3, and D 2A , D 2B It has a high affinity for D4 receptors and also interacts with serotonin receptor subtypes, including 5-HT7, 5-HT 5A , 5-HT 1A , 5-HT 1B , 5-HT 2C , 5-HT 2B , 5-HT 2A and 5-HT6, in most cases ASM behaves as an antagonist and can be used to treat acute schizophrenia in adults, acute mania, and bipolar disorder in children.

[0005]

[0006] Asenapine maleate is extensively metabolized in the liver and gastrointestinal tract, and its oral bioavailability is less than 2%. The sublingual tablet (Saphris) developed by Schering-Plough can increase its bioavailability to 35% through sublingual administration, but the preparation, transportation, and storage costs of sublingual tablets are high and the patient compliance is low (no food or water should be taken for 10 minutes after taking it). In view of the difficulties encountered by the above clinical preparations, it is necessary to develop an oral preparation with good absorption, rapid onset, and high patient compliance.

[0007] The oral mucosal drug delivery system refers to a new type of drug delivery system in which the preparation acts on the oral cavity to exert local treatment or is directly absorbed into the systemic circulation through the oral mucosa to exert systemic treatment. It has been regarded as an effective alternative to conventional oral and parenteral administration. The oral physiological environment is mild, the pH value is close to neutral and the enzyme activity is low. The drug is absorbed through the mucosa without first-pass metabolism in the liver. It has the characteristics of convenient administration, easy removal, and high patient compliance. Compared with other mucosa, the oral mucosa is not easily damaged, the cells are quickly renewed and repaired, it has certain permeability, firmness and strong resistance to mechanical irritation, and it has stronger tolerance to potential allergens, which can reduce irreversible irritation or damage caused by drug administration.

[0008] So far, some invention patents have provided methods for preparing asenapine maleate oral dissolving films to simplify the preparation process and improve oral absorption. Patent CN 104000800 A discloses an asenapine maleate oral dissolving film, which has a simple preparation process and convenient packaging, transportation and storage compared to sublingual tablets, but an organic solvent (ethanol or acetone) is used in the preparation process, and a large amount of organic solvent will volatilize in industrial production, and there is a problem of organic solvent residue in the final system; Patent CN102657635A discloses a method for preparing a sponge-like asenapine sublingual film with micropores, which uses silicon dioxide as a pore-forming agent, and forms micropores on the surface of the film by high-temperature volatilization of an organic solvent. This film will form a large amount of organic solvent residues, and the uniformity of the film is difficult to control due to the uneven distribution of the number of micropores, and it is difficult to ensure the accuracy of the dosage. Asenapine maleate has poor water solubility and is extensively metabolized in the body, while the sublingual mucosa can significantly increase its oral bioavailability. However, the above methods do not improve the solubility of the drug, and all have the problem of short sublingual residence time, and cannot fundamentally improve the oral absorption of the drug.

[0009] Self-nanoemulsion system is a new technology in the field of pharmaceutical preparations in recent years. Asenapine maleate can be dissolved in a mixed system of one or more oils, surfactants and co-surfactants to prepare a self-nanoemulsion drug delivery preparation of asenapine maleate. When the self-nanoemulsion system comes into contact with water, it will spontaneously emulsify to form micron or nanometer-sized emulsion droplets, which are called self-microemulsion system and self-nanoemulsion system, respectively. Since the drug (API) in the self-nanoemulsion system is already in a dissolved state, compared with the dissolution of solid API, the API in the self-nanoemulsion system can directly skip the dissolution process, has a faster dissolution or penetration rate, and can effectively solve the problem of poor water solubility and low bioavailability of asenapine maleate. Compared with emulsions, self-emulsifying drug delivery systems are thermodynamically stable systems, have more stable physical and chemical properties, are easy to prepare, and can quickly emulsify to form fine microemulsions at appropriate temperatures and moderate movements in the oral cavity or gastrointestinal tract, thereby increasing drug solubility, permeability and bioavailability. However, in actual production and use, there are problems such as high production cost, inconvenient transportation and storage, and low drug loading. The use of large doses of surfactants can also cause mucosal irritation. Generally, it is encapsulated in capsules for oral administration, with a single dosage form, and is prone to problems such as capsule shell compatibility, drug precipitation and leakage. By solidifying the liquid self-emulsifying system in different ways to form a solid self-emulsifying system, the stability of the drug can be significantly improved, the shortcomings of liquid preparations in production, storage and transportation can be effectively improved, and the dosage form selection can be increased, expanding the scope of drug application.

[0010] Nanocrystal drugs (NC) refer to crystalline or amorphous drugs with a size less than 1 μm, no carrier, and a small amount of stabilizer that can exist stably. Usually, NC often exists in the form of crystalline dispersed particles. When it is dispersed in a liquid, it is called a nanosuspension, which includes nanocrystals, stabilizers, and liquid dispersion media. Nanosuspensions significantly improve the solubility and dissolution rate of drugs by reducing the particle size of APIs. They have the advantages of simple prescription, high safety, high bioavailability, and large drug loading. Nanosuspensions can improve drug solubility, enhance drug penetration and diffusion in the oral mucosa, and oral dissolving films can circumvent extensive metabolism in the liver and gastrointestinal tract. The combination of the two can effectively improve the oral bioavailability of poorly soluble drugs. It is a new delivery method that is efficient, low-cost, and easy to prepare. In addition, the physical stability of nanosuspensions is the main challenge in their development and application. Oral dissolving films can not only realize the solidification of nanosuspensions, improve their stability, but also maintain the rapid release characteristics of their preparations, which also provides a new option for the solidification of nanosuspensions.

[0011] At present, there are relatively few reports on self-nanoemulsion and nanocrystalline oral membranes in China. Patent CN 113209052 A discloses a cannabidiol self-nanoemulsion buccal membrane, which can greatly improve the in vitro dissolution rate and oral mucosal permeation rate of the drug; Patent CN 109172547A discloses a self-microemulsified oral fast-dissolving film for pets and its preparation method. For many drugs with strong fat solubility, good permeability and low oral bioavailability, the core problem has not been improved or solved. The traditional oral administration method has obvious first-pass effect and low bioavailability. The oral mucosal drug delivery system is a new drug delivery route developed to replace the traditional systemic administration route. Compared with the traditional oral administration route, the drug can be absorbed through the oral mucosa and directly enter the systemic circulation, thereby avoiding degradation by gastrointestinal enzymes and the first-pass effect of the liver. The drug can quickly reach an effective blood drug concentration, increase drug absorption, and improve the bioavailability of the drug. Compared with the gastrointestinal absorption route, the dosage can be reduced and the related side effects can be reduced; oral films have suitable mechanical properties and are easy to transport and store; they have accurate dosage and good taste, which can improve patient compliance with medication, and are especially suitable for the elderly, mentally ill patients and children with dysphagia.

[0012] So far, no patents related to asenapine maleate self-nanoemulsion oral adhesive film and nanocrystalline oral adhesive film have been reported. Summary of the invention

[0013] Based on the physicochemical properties of the drug itself, the advantages and limitations of existing preparations, and the advantages of self-nanoemulsions and nanosuspensions combined with oral mucosa administration, the present invention aims to provide an asenapine maleate self-nanoemulsion oral adhesive film and an asenapine maleate nanocrystal oral adhesive film preparation, which can improve the solubility of API and has the advantages of high drug loading, rapid onset, rapid absorption and high bioavailability, and the preparation has excellent mechanical properties and is conducive to storage, transportation and use.

[0014] The asenapine maleate self-nanoemulsion oral adhesive film preparation of the present invention is mainly composed of an asenapine maleate self-nanoemulsion system, a film-forming material, an adhesive material, a solid adsorbent and a taste masking agent. The self-nanoemulsion oral adhesive film preparation is prepared by dissolving asenapine maleate in the self-nanoemulsion system, adsorbing the solid adsorbent and then dispersing the solid adsorbent in the film-forming material to form an oral adhesive film. The self-nanoemulsion system comprises an oil phase, an emulsifier and an auxiliary emulsifier. The droplet size of the self-nanoemulsion system is 10 to 300 nm, preferably 20 to 150 nm.

[0015] The particle size of the emulsion droplets formed after the preparation is re-dissolved is 10 to 300 nm, preferably 20 to 150 nm.

[0016] The content of the self-nanoemulsification system in the asenapine maleate self-nanoemulsification oral adhesive film preparation is 1-80% w / w, preferably 3-70% w / w, and more preferably 10-60% w / w.

[0017] The oil phase contained in the self-nanoemulsion system refers to a pharmaceutically acceptable oil or oily substance, selected from: soybean oil, castor oil, corn oil, olive oil, sesame oil, sunflower oil, peanut oil, long-chain monoglycerides, long-chain triglycerides, medium-chain triglycerides, caprylic capric triglycerides, caprylic capric mono- and diglycerides, monooleic glyceryl, monolinoleic glyceryl, glyceryl monolinoleate, propylene glycol fatty acid esters, propylene glycol monolaurate, caprylic / capric / succinic triglycerides, vitamin E, fatty acids and fatty acid esters, mineral oils or any combination thereof.

[0018] In the self-nanoemulsion oral adhesive film preparation of the present invention, the hydrophilic-hydrophobic balance (HLB value) of the oil phase is 8 to 18. The content of the oil phase in the self-nanoemulsion system is 5-75% w / w, preferably 10-60% w / w, more preferably 15-50% w / w.

[0019] The self-nanoemulsion system in the self-nanoemulsion oral adhesive film preparation provided by the present invention also contains an emulsifier, which adopts various pharmaceutically acceptable non-ionic surfactants, cationic surfactants, anionic surfactants, zwitterionic surfactants or any combination thereof. Specifically selected from perfluorooctane sulfonate (PFOS), sodium dodecyl sulfate (SDS), ammonium lauryl sulfate and other alkyl sulfates, sodium dodecyl ether sulfate (SLES) and alkylbenzene sulfonate, Tween 20 or 80, Span 80 or 85, poloxamer, caprylic acid capric acid polyethylene glycol glyceride, polyoxyethylene (35) castor oil ELP, polyoxyethylene ether castor oil, polyoxyethylene ether hydrogenated castor oil, fatty acid polyethylene glycol glyceride, polyoxyethylene dehydrated sorbitan fatty acid ester and phospholipids. The hydrophilic-hydrophobic balance value (HLB value) of the surfactant is 11 to 16.

[0020] The content of the emulsifier in the self-nanoemulsification system is 10-50% w / w, preferably 20-45% w / w.

[0021] The self-nanoemulsion system in the self-nanoemulsion oral adhesive film preparation provided by the present invention further comprises an emulsifier. The emulsifier is selected from one or more of ethanol, propylene glycol, n-propanol, isopropanol, n-butanol, isobutanol, n-pentanol, isopentanol, 1-hexanol, 2-hexanol, 1-octanol, 2-octanol, fusel oil, polyethylene glycol, dimethyl isosorbide, propylene carbonate, diethylene glycol monoethyl ether, tetrahydrofuran polyethylene glycol ether and glycerol.

[0022] The content of the co-emulsifier in the self-nanoemulsification system is 3-30% w / w, preferably 5-40% w / w.

[0023] The solid adsorbent used in the self-nanoemulsion oral adhesive film preparation of the present invention is various pharmaceutically acceptable solid adsorbents, selected from one or more of microcrystalline cellulose, lactose, pregelatinized starch, talc, silicon dioxide, mannitol, PEG 4000 and PEG 6000.

[0024] The asenapine maleate nanocrystalline oral adhesive film preparation of the present invention is mainly composed of asenapine maleate nanosuspension, film-forming material, adhesive material, plasticizer and taste masking agent. The asenapine maleate nanosuspension is prepared by wet grinding, and the nanosuspension is dispersed in a film-forming glue to form a bioadhesive film. The nanoparticles formed by the preparation after redissolution have a particle size of 10 to 500 nm, preferably 20 to 350 nm.

[0025] The nanosuspension is prepared from a drug and a stabilizer, the content of the nanosuspension in the asenapine maleate nanocrystal oral adhesive film preparation is 10-60% w / v, the particle size of the nanosuspension is 10-400 nm, the concentration of asenapine maleate in the nanosuspension is 1%-6% w / v, preferably 1%-3% w / v; the volume ratio of the nanosuspension to the film-forming glue is 3:7. The stabilizer is selected from one or two of Tween 20, Tween 80, Poloxamer 188, hydroxypropyl methylcellulose, sodium lauryl sulfate, and polyethylene caprolactam-polyvinyl acetate-polyethylene glycol graft copolymer (Soluplus), preferably Soluplus.

[0026] Further, the concentration of the stabilizer Soluplus is 0.25%-5% w / v, preferably 0.5%-1% w / v;

[0027] In the nanocrystalline oral adhesive film preparation of the present invention, the plasticizer is selected from any one of polyethylene glycol 400, glycerol, 1,2-propylene glycol, silicone oil, mannitol, and sorbitol, or a mixture of any two of them in any proportion, preferably polyethylene glycol 400 or glycerol.

[0028] In the two oral adhesive film preparations described in the present invention, the taste masking agent is sucralose.

[0029] The film-forming material used in the present invention is a pharmaceutically acceptable polymer film-forming material, including a water-soluble polymer, a water-insoluble polymer, or a combination of one or more water-soluble polymers and / or water-insoluble polymers. The film-forming material is specifically selected from hydroxypropyl methylcellulose (HPMC), hydroxypropyl cellulose (HPC), polyvinyl alcohol (PVA), hydroxypropyl methylcellulose, sodium carboxymethyl cellulose, polyvinyl pyrrolidone (PVP) K90, polyvinyl alcohol-polyethylene glycol copolymer, xanthan gum, tragacanth gum, sodium alginate, pullulan or a combination thereof.

[0030] Furthermore, the content of the film-forming material of the present invention is 10%-60% w / v, preferably 10%-40% w / v.

[0031] The adhesive material used in the present invention is a pharmaceutically acceptable bioadhesive material, including one or two of sodium carboxymethylcellulose, carbomer, polycarbophil, chitosan, polyvinyl pyrrolidone (PVP) K90, carrageenan, xanthan gum, gelatin, guar gum, gum arabic, polyacrylic acid, methyl methacrylate copolymer, copolymer of acrylic acid and alkyl acrylate, sodium hydroxypropyl methylcellulose, and hydroxypropyl methylcellulose.

[0032] Furthermore, the content of the adhesive material of the present invention is 1%-20% w / v, preferably 2%-20% w / v.

[0033] Furthermore, in the formulation of the asenapine maleate self-nanoemulsion oral adhesive film, the mass ratio of asenapine maleate, propylene glycol monocaprylate, polyoxyethylene (35) castor oil ELP and diethylene glycol monoethyl ether is 28:360:296:148.

[0034] Furthermore, the prescription of the asenapine maleate self-nanoemulsion oral adhesive film is:

[0035]

[0036] The dosage of the asenapine maleate self-nanoemulsion oral adhesive film preparation prepared by the present invention is 2.5 mg / tablet, and the above prescription is for a batch of 1000 tablets.

[0037] The present invention also provides a method for preparing an asenapine maleate self-nanoemulsion oral adhesive film preparation, which is specifically as follows:

[0038] a. Mix the drug with the oil phase, emulsifier and co-emulsifier, and stir in a 37°C water bath to fully dissolve the drug to form an asenapine maleate self-nanoemulsion system;

[0039] b. Dispersing the film-forming material and the adhesive material in water and stirring to dissolve to form a uniform film-forming glue;

[0040] c. The asenapine maleate from step a is poured into the film-forming gel of step b under stirring at room temperature, and a solid adsorbent is added after forming a nanoemulsion, and stirred until uniformly dispersed to allow sufficient adsorption;

[0041] d. Add pigments, taste masking agents, etc., stir evenly at room temperature, let stand to degas, use a coating machine to spread the film, set the scraper height to 1.0 mm, the coating speed to 20 mm / s, and dry at 40°C for 2 h after coating. When the temperature returns to room temperature, demold the asenapine maleate self-nanoemulsion oral adhesive film preparation.

[0042] The asenapine maleate self-nanoemulsion oral adhesive film preparation provided by the present invention is prepared by adjusting the ratios and dosages of the oil phase, the emulsifier, the co-emulsifier and the asenapine maleate in the self-nanoemulsion system, and screening the optimal formulation composition of the asenapine maleate self-nanoemulsion by examining the particle size, PDI, emulsification ability and stability of the self-nanoemulsion system. The film-forming material and the solid adsorbent are determined by examining the appearance, mechanical properties and formulation compatibility of the film, the adhesive material is determined according to the adhesion, in vitro retention time, mechanical properties and formulation compatibility, and the optimal asenapine maleate self-nanoemulsion oral adhesive film preparation formulation is determined by examining the drug loading of the film, the change in particle size after redissolution, the appearance and mechanical properties of the film.

[0043] In the present invention, in the prescription of the asenapine maleate nanocrystalline oral adhesive film preparation, the mass ratio of asenapine maleate to Soluplus is 360:60.

[0044] Furthermore, the prescription of the asenapine maleate nanocrystalline oral adhesive film is:

[0045]

[0046] The dosage of the asenapine maleate nanocrystalline oral adhesive film preparation prepared by the present invention is 2.5 mg / tablet, and the above prescription is for a batch of 1000 tablets.

[0047] The present invention also provides a method for preparing an asenapine maleate nanocrystalline oral adhesive film preparation, which is specifically as follows:

[0048] a. The drug, stabilizer, grinding medium and grinding beads are weighed in appropriate amounts according to the ratio of each prescription and placed in a grinding tube, mixed evenly to form a coarse suspension, and asenapine maleate nanosuspension is prepared by wet grinding;

[0049] b. Dispersing the film-forming material and the adhesive material in water and stirring to dissolve to form a uniform film-forming glue;

[0050] c. Pour the asenapine maleate nanosuspension of step a into the film-forming gel of step b under stirring at room temperature and stir evenly;

[0051] d. Add plasticizer, taste masking agent and pigment, stir evenly at room temperature, let stand to degas, use a coating machine to spread the film, set the scraper height to 1.0 mm, the coating speed to 20 mm / s, dry at 40°C for 2 h after coating, wait until the temperature returns to room temperature, and demold to obtain the asenapine maleate nanocrystal oral adhesive film preparation.

[0052] The asenapine maleate nanocrystalline oral adhesive film provided by the present invention determines the nanosuspension prescription by adjusting the drug concentration, stabilizer type and concentration, grinding bead size, etc. in the nanosuspension prescription, and further screens the grinding time, grinding frequency, etc. to determine the preparation process of the nanosuspension. On the basis of the self-nanoemulsion oral adhesive film, the prescription of the nanocrystalline oral adhesive film is further determined, the plasticizer and the amount of the nanosuspension are screened, and finally the asenapine maleate nanocrystalline oral adhesive film is coated.

[0053] The asenapine maleate oral adhesive film preparation of the present invention can be used for treating acute schizophrenia, acute mania in adults and bipolar mania in children.

[0054] The beneficial effects of the present invention compared with the prior art are as follows:

[0055] 1. Provide the process and prescription of two preparation methods of asenapine maleate self-nanoemulsion and nanosuspension. The two nanoformulations can improve the mucosal absorption of drugs by improving the dissolution and dissolution of drugs, promoting the diffusion of drugs in the mucus layer, increasing the absorption and penetration of drugs in the oral mucosa, and prolonging the oral retention time of drugs, thereby improving oral bioavailability. Both can be combined with oral adhesive membranes to achieve drug delivery through the sublingual mucosa. The drugs are absorbed directly into the blood through the abundant submucosal blood vessels, which can avoid degradation in the gastrointestinal tract and the first-pass effect of the liver, thereby improving the oral absorption efficiency of ASM.

[0056] 2. The oral adhesive film preparation of asenapine maleate provided by the present invention can be quickly hydrated and adhered to the oral mucosa after contacting a small amount of saliva, and is not easy to fall off. Patients with mental illness are extremely emotionally unstable, and some patients have the behavior of hiding or spitting out drugs. The oral adhesive film does not need to be swallowed, and can quickly adhere and release drugs after sublingual administration. It can exert its efficacy in a short time to stabilize the patient's mood, and greatly improve the patient's medication compliance.

[0057] 3. The present invention creatively introduces a solid adsorbent to adsorb the self-nanoemulsion, which can improve the mechanical properties of the self-nanoemulsion oral adhesive film. The combination of the self-nanoemulsion and nanosuspension with the oral film also provides a new option for the solidification method of the above preparations, which can effectively solve the long-standing problems of poor stability and low patient compliance of the self-nanoemulsion and nanosuspension.

[0058] 4. The present invention combines self-nanoemulsion technology and nanocrystals with oral adhesive film. Self-nanoemulsion can improve the solubility of asenapine maleate. Its lower surface tension is conducive to penetrating the mucosal hydration layer and enhancing mucosal absorption. Nanocrystals can improve the solubility and dissolution rate of API, increase the drug concentration gradient near the oral mucosa, and promote drug diffusion and oral absorption. The oral adhesive film can adhere to the sublingual and quickly release the drug. The drug is absorbed directly into the systemic circulation through the abundant submucosal blood vessels, avoiding gastrointestinal and liver metabolism, thereby enhancing oral bioavailability. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 It is the particle size distribution of asenapine maleate self-nanoemulsion oral adhesive film preparation after re-dissolving in water;

[0060] Figure 2 It is the particle size distribution of asenapine maleate nanocrystalline oral adhesive film preparation after being re-dissolved in water;

[0061] Figure 3 The in vitro dissolution curves of asenapine maleate self-nanoemulsion oral adhesive film and asenapine maleate nanocrystal oral adhesive film preparations;

[0062] Figure 4In vivo pharmacokinetic and blood concentration curves of asenapine maleate self-nanoemulsion oral adhesive film and asenapine maleate nanocrystal oral adhesive film preparations. DETAILED DESCRIPTION

[0063] The present invention is described in detail below with reference to the embodiments, but the embodiments of the present invention are not limited thereto. Obviously, the embodiments described below are only partial embodiments of the present invention. For those skilled in the art, other similar embodiments obtained without creative labor all fall within the protection scope of the present invention.

[0064] Example 1

[0065] Preparation of Asenapine Maleate Self-nanoemulsion

[0066] 1. Screening of oil phase, emulsifier and co-emulsifier

[0067] Solubility determination of asenapine maleate in different oil phases, emulsifiers and co-emulsifiers: The equilibrium solubility determination was carried out by the classic shake flask method. 1 g of oil phase, emulsifier and co-emulsifier were added to centrifuge tubes respectively, and then 1 mg of asenapine maleate was added to each centrifuge tube respectively. The tubes were vortexed for 2 min, and an appropriate amount of asenapine maleate was added according to the dissolution conditions so that the oil phase always had visible drug solids. The tubes were shaken in a 37°C constant temperature water bath for 48 h (100 rpm), taken out and centrifuged (13000 rpm, 20 min); 0.3 mL of the supernatant was aspirated and transferred to a 10 mL volumetric flask, and the mobile phase was added to the scale line. An appropriate amount of solution was taken and filtered with a 0.45 μm microporous filter membrane, and the filtrate was added to the injection bottle. The drug solubility was determined by high performance liquid chromatography. The solubility determination results of ASM in different oil phases, emulsifiers and co-emulsifiers are shown in Table 1.

[0068] Table 1 Solubility of ASM in different oil phases, emulsifiers and co-emulsifiers

[0069]

[0070] The screened oil phase, emulsifier and co-emulsifier include caprylic capric acid mono- and diglycerides, polyoxyethylene (35) castor oil, diethylene glycol monoethyl ether, medium chain glycerides, soybean oil, caprylic capric acid macrogol glycerides, peppermint oil, Tween 20, Tween 60, Tween 80, sesame oil, oleyl alcohol, polyethanol-7-stearate, polyoxyethylene 40 hydrogenated castor oil, PEG400, oleoyl polyoxyethylene glyceride, lauric acid macrogol glyceride, and propylene glycol monocaprylate.

[0071] 2. Screening of self-nanoemulsion prescriptions

[0072] The oil phase, emulsifier and co-emulsifier were determined in combination with the solubility and pseudo-ternary phase diagram. The proportion of each component was determined according to the particle size, PDI, emulsification time, transmittance and emulsion stability of the self-nanoemulsion. The final self-nanoemulsion formula was: propylene glycol monocaprylate (45.0%), polyoxyethylene (35) castor oil (37.0%) and diethylene glycol monoethyl ether (18.0%). The measured particle size was 45.54±0.75nm, the PDI was 0.18±0.05, and the drug loading was 3.5%.

[0073] Example 2

[0074] Preparation of Asenapine Maleate Nanosuspension

[0075] Asenapine maleate nanosuspension was prepared by wet grinding method. An appropriate amount of stabilizer was weighed into a grinding tube, 1 mL of purified water was injected, asenapine maleate was added, and it was shaken to disperse to obtain a coarse suspension. Finally, a certain amount of 0.5 mm zirconium oxide grinding beads was added, the grinding tube was placed in a grinder, and the grinding parameters were adjusted to grind to obtain asenapine maleate nanosuspension.

[0076] The single-factor variable method was used to screen the stabilizer of the nanosuspension and its concentration, and the grinding time and drug loading were used to further optimize the prescription, resulting in a nanosuspension with a drug concentration of 3% w / v and a stabilizer Soluplus concentration of 0.5% w / v. The grinding time was 60 min, the grinding frequency was 60 Hz, the particle size was 124.20±2.46 nm, and the PDI was 0.13±0.09.

[0077] Example 3

[0078] Preparation of Asenapine Maleate Self-nanoemulsion Oral Adhesive Films (ASM@SNE-OMFs)

[0079] The present invention adopts a solvent casting method to prepare an asenapine maleate self-nanoemulsion oral adhesive film preparation. Film-forming materials and adhesive materials are added to purified water in a certain proportion to dissolve, added to the self-nanoemulsion, stirred evenly, then added with a solid adsorbent, stirred to fully adsorb the self-nanoemulsion, and finally added with a taste masking agent, and coated and dried to obtain a self-nanoemulsion oral adhesive film preparation. The film-forming materials of this step are preferably hydroxypropyl methylcellulose and polyvinyl alcohol, and the adhesive materials are preferably carbomer 934P, sodium hydroxypropyl methylcellulose, hydroxypropyl methylcellulose K4M and polyvinyl pyrrolidone K90. The film-forming materials and adhesive materials are weighed in appropriate proportions, and the optimal prescription is determined according to the appearance, mechanical properties and adhesion ability of the film, and the drug loading of the film is determined by examining the drug content and particle size changes.

[0080] Table 2 Investigation of drug loading of asenapine maleate self-nanoemulsion oral adhesive film preparation

[0081]

[0082] Example 4

[0083] Preparation of Asenapine Maleate Nanocrystal Oral Adhesive Film (ASM@NC-OMFs)

[0084] The present invention adopts solvent casting method to prepare asenapine maleate nanocrystalline oral adhesive film preparation. Film-forming material and adhesive material are added to purified water in a certain proportion to dissolve, then nano suspension is added, stirred evenly, taste masking agent and plasticizer are finally added, fully stirred to make the film-forming glue liquid dispersed evenly, and coated and dried to obtain the nanocrystalline oral adhesive film preparation. The film-forming material and adhesive material of the asenapine maleate nanocrystalline oral adhesive film are based on the self-nanoemulsion oral adhesive film, and the two are basically the same. However, since the self-nanoemulsion system itself has a large amount of oil phase, it can play the role of plasticizer, so no plasticizer is added, while the nanocrystalline oral adhesive film needs to add a plasticizer to improve the mechanical properties of the film, and the volume ratio of the nano suspension and the film-forming glue liquid is determined by the film loading amount, and the results are shown in Table 3.

[0085] Table 3 Investigation of drug loading of asenapine maleate nanocrystal oral adhesive film preparation

[0086]

[0087] The specific prescription is as follows:

[0088] Asenapine maleate self-nanoemulsion oral adhesive film 1

[0089]

[0090] * Used in the formulation but removed during the process. Asenapine Maleate Self-nanoemulsion Oral Adhesive Film 2

[0091]

[0092] * Used in the formulation but removed during the process. Asenapine Maleate Self-nanoemulsion Oral Adhesive Film 3

[0093]

[0094]

[0095] *Used in formulation but removed during processing.

[0096] Asenapine maleate self-nanoemulsion oral adhesive film 4

[0097]

[0098] *Used in formulation but removed during processing. Formulations 1-4 above were used to compare adhesive materials.

[0099] Asenapine maleate self-nanoemulsion oral adhesive film 5

[0100]

[0101] *Used in the recipe but removed during processing. Recipe 5 is used to compare the film-forming materials with recipe 1.

[0102] Asenapine Maleate Nanocrystal Oral Adhesive Film 6

[0103]

[0104] * Used in the formulation but removed during the process. Asenapine Maleate Nanocrystalline Oral Adhesive Film 7

[0105]

[0106] *Used in formulation but removed during processing. Formulation 7 was used to compare adhesive materials.

[0107] Asenapine Maleate Nanocrystal Oral Adhesive Film 8

[0108]

[0109] *Used in the formulation but removed during processing. Formulation 8 was used for comparison of film-forming materials.

[0110] Example 5

[0111] Determination of the thickness of asenapine maleate oral adhesive film preparations

[0112] The different positions of the film obtained by coating were cut into three small films of 2 cm × 3 cm, and the thickness of the two preparations was measured by a five-point sampling method using an electronic spiral micrometer (resolution: 0.001 mm), i.e., the four corners and the center of the film. Five values ​​were recorded and the average value was calculated to obtain the thickness of the oral adhesive film preparation.

[0113] Example 6

[0114] Mechanical property evaluation

[0115] (1) Determination of tensile strength and elongation at break

[0116] Cut the film into strips of 20mm×150mm, fix the two ends in the left and right clamps of the electronic stripping machine, control the tightness of the sample, and keep it in a state of being just straightened but not taut. Set the stretching speed to 30mm / min. After the test starts, the right clamp of the electronic stripping machine moves automatically, and the sensor sensing force value and elongation are recorded. Three groups are measured in parallel, and the average value is recorded. The calculation formula for the tensile strength and elongation at break of the film is as follows:

[0117]

[0118]

[0119] (2) Folding endurance test

[0120] A 2 cm×3 cm film was folded repeatedly at the same position and in the same direction until the film broke, and the number of folds was recorded and the average value was taken (n=3).

[0121] Example 7

[0122] Adhesion time assay

[0123] The two oral adhesive films were cut into circular sheets with a diameter of 1.5 cm, lightly moistened with simulated saliva (pH 6.8), and attached to the surface of the pig buccal membrane. The retention time of the film was determined using a disintegration device (37°C, 50 rpm). The film moved vertically up and down. When moving downward, the film and the pig buccal membrane must be completely submerged in the medium solution. The time when the film dissolves or falls off is recorded as the adhesion time.

[0124] Example 8

[0125] Adhesion test

[0126] The adhesion of asenapine maleate self-nanoemulsion oral adhesive film and nanocrystal oral adhesive film preparations was determined by texture analyzer. The porcine buccal membrane was cut into 1.5 cm × 1.5 cm square membranes and adhered to the punch of the texture analyzer. The preparation was then placed in a surface dish, moistened with simulated saliva, and then placed on the lower end bracket of the texture analyzer. The texture analyzer punch was lowered at a speed of 1 mm / s. When the porcine buccal membrane on the punch came into contact with the preparation, a force of 0.5 N was applied to the punch for 60 seconds. Then the punch was raised at a speed of 1 mm / s to separate the porcine buccal membrane from the preparation. The force at the time of separation was recorded as the adhesion. The adhesion of asenapine maleate self-nanoemulsion oral adhesive film and nanocrystal oral adhesive film and the two preparations without PVP K90 were measured.

[0127] According to Examples 5 to 8, the mechanical properties, adhesion and adhesion time of asenapine maleate oral adhesive film preparations (F1 SNEDDS-OMFs to F5SNEDDS-OMFs, F6 NC-OMFs to F8 NC-OMFs) (formulations of Examples 1-8) were measured. The results are shown in Table 4.

[0128] As shown in Table 4, the formulations containing carbomer, sodium hydroxypropyl methylcellulose and hydroxypropyl methylcellulose K4M (F2SNEDDS-OMFs, F3SNEDDS-OMFs, F4SNEDDS-OMFs and F7NC-OMFs) have poor film-forming properties and poor appearance. From the test results in the table, it can be seen that although the retention time is long, the film is thick, there are a lot of bubbles on the surface, and the folding endurance, elongation at break and tensile strength are poor. The formulation with hydroxypropyl methylcellulose as the film-forming material has slightly poor adhesion and adhesion time. Comprehensively considering the parameters such as film thickness, folding endurance, elongation at break, tensile time, adhesion and adhesion time and the above requirements, F1SNEDDS-OMFs and F6NC-OMFs were finally selected as the optimal formulations.

[0129] Table 4 Film formulation characteristics

[0130]

[0131] Example 9

[0132] Determination of particle size of asenapine maleate oral adhesive film preparation after reconstitution / hydration

[0133] The homemade asenapine maleate self-nanoemulsion oral adhesive film and nanocrystalline oral adhesive film preparations were re-dissolved in water, and their particle sizes were measured and compared with the particle sizes of liquid self-nanoemulsion systems and nanosuspensions containing asenapine maleate, to investigate the effects of combining self-nanoemulsions, nanosuspensions with oral adhesive films and during the entire formulation process on particle size.

[0134] like Figure 1 As shown in the figure, the average particle size of asenapine maleate after reconstitution in the nanoemulsion oral adhesive film preparation was 125.88±2.61nm, and the PDI was 0.17±0.08; Figure 2 As shown in the figure, the average particle size of the maleic acid asenapine nanocrystal oral adhesive film preparation after reconstitution is 325.10±5.03nm, and the PDI is 0.30±0.06. It can be seen that after the maleic acid asenapine self-nanoemulsion and nanocrystals are loaded into the oral adhesive film, the particle size increases slightly, but remains within a relatively small range, and the particle size is uniform, which is conducive to the diffusion of the maleic acid asenapine self-nanoemulsion and nanocrystals in the mucus layer and enhances the mucosal permeability of the drug.

[0135] Example 10

[0136] Evaluation of in vitro dissolution of asenapine maleate in oral adhesive film

[0137] The present invention designs two oral adhesive films that need to be taken sublingually. In order to simulate the oral environment as much as possible, the present invention selects simulated saliva as the dissolution medium, and the volume is 20mL. Asenapine maleate self-nanoemulsion oral adhesive film preparation, asenapine maleate nanocrystal oral adhesive film preparation and asenapine maleate raw material are respectively added to 20mL of release medium, and 1mL of medium is taken at 1, 2, 4, 6, 8, 12, 16, 20, 30, 60 and 120min under the conditions of 37±1°C and 100r / min (the same temperature and the same amount of corresponding medium are then supplemented), insoluble impurities are filtered to remove, 20μL is taken and injected into a high performance liquid chromatograph to determine the drug content, and the dissolution rate is calculated.

[0138] The results are as follows Figure 3 As shown in the figure, the dissolution rates of asenapine maleate from the nanoemulsion oral adhesive film and the asenapine maleate nanocrystal oral adhesive film are basically similar. The nanocrystal oral adhesive film can dissolve 90% within 15 minutes, and the self-nanoemulsion oral adhesive film can dissolve 92% within 30 minutes, which are significantly higher than the asenapine maleate raw material.

[0139] Embodiment 11

[0140] Evaluation of the pharmacokinetics of asenapine maleate in oral adhesive film in vivo

[0141] The present invention compares the oral bioavailability of three test preparations ASM@SNE-OMFs, ASM@NC-OMFs and ASM sublingual tablets in rats. 18 SD rats (male) were divided into three groups, fasted for 12 hours before administration, and had free access to water. During administration, the rats were anesthetized with ether, and the sublingual membrane and sublingual tablets were delivered to the sublingual part of the rats by tweezers and moistened with 0.2mL simulated saliva. The dosage of the three groups was controlled to be 2.4mg / kg. 0.5mL of blood was taken into a 0.5mL centrifuge tube rinsed with heparin sodium solution 5min, 15min, 30min, 1h, 2h, 4h, 8h, 12h, and 24h after administration, and the supernatant plasma was taken at 13000rpm for 5min.

[0142] The plasma samples were extracted by liquid-liquid extraction and then analyzed by UPLC-MS / MS.

[0143] Blood drug concentration curve Figure 4 The pharmacokinetic data are shown in Table 5. When asenapine maleate sublingual tablets were used as the reference preparation, the AUC of asenapine maleate self-nanoemulsion oral adhesive film was (0-24h) and C max The AUC of asenapine maleate nanocrystal oral adhesive film was increased by 1.39 times and 1.45 times respectively. (0-24h) and C maxThe AUC of ASM@SNE-OMFs and ASM@NC-OMFs compared with ASM sublingual tablets was 1.27 and 1.33 times higher, respectively. (0-24h) and C max There were significant differences, indicating that ASM@SNE-OMFs and ASM@NC-OMFs could significantly improve the oral bioavailability of ASM.

[0144] Table 5 Pharmacokinetic parameters

[0145]

[0146] *p<0.05, comparing ASM@SNE-OMFs and ASM@NC-OMFs with ASM sublingual tablets.

Claims

1. An asenapine maleate self-nanoemulsion oral adhesive film preparation, characterized in that: The invention mainly comprises an asenapine maleate self-nanoemulsion system, a film-forming material, an adhesive material, a solid adsorbent and a taste-masking agent; the self-nanoemulsion oral adhesive film preparation is prepared by dissolving asenapine maleate in the self-nanoemulsion system, adsorbing the asenapine maleate in the solid adsorbent and then dispersing the asenapine maleate in the film-forming material to form an oral adhesive film; the self-nanoemulsion system comprises an oil phase, an emulsifier and an auxiliary emulsifier; the emulsion droplet particle size formed after the preparation is redissolved is 10 to 300 nm; the content of the self-nanoemulsion system in the asenapine maleate self-nanoemulsion oral adhesive film preparation is 10-60% w / w.

2. The asenapine maleate self-nanoemulsion oral adhesive film preparation according to claim 1, characterized in that: The oil phase contained in the self-nanoemulsion system refers to a pharmaceutically acceptable oil or oily substance selected from: soybean oil, castor oil, corn oil, olive oil, sesame oil, sunflower oil, peanut oil, long-chain monoglycerides, long-chain triglycerides, medium-chain triglycerides, caprylic capric triglycerides, caprylic capric acid mono- and diglycerides, monooleic glyceride, monolinoleic glyceride, glyceryl monolinoleate, propylene glycol fatty acid ester, propylene glycol monolaurate, caprylic / capric / succinic triglyceride, vitamin E, fatty acids and fatty acid esters, mineral oil or any combination thereof; the hydrophilic-hydrophobic balance value of the oil phase is 8-18; the content of the oil phase in the self-nanoemulsion system is 15-50% w / w; The emulsifier contained in the self-nanoemulsion system is a pharmaceutically acceptable nonionic surfactant, a cationic surfactant, an anionic surfactant, a zwitterionic surfactant or any combination thereof, specifically selected from perfluorooctane sulfonate, sodium dodecyl sulfate, ammonium lauryl sulfate and other alkyl sulfates, sodium dodecyl ether sulfate and alkylbenzene sulfonate, Tween 20 or 80, Span 80 or 85, poloxamer, caprylic acid capric acid macrogol glyceride, polyoxyethylene (35) castor oil ELP, polyoxyethylene ether castor oil, polyoxyethylene ether hydrogenated castor oil, fatty acid macrogol glyceride, polyoxyethylene dehydrated sorbitan fatty acid ester and phospholipids. The hydrophilic-hydrophobic balance value of the surfactant is 11-16. The content of the emulsifier in the self-nanoemulsion system is 20-45% w / w. The co-emulsifier contained in the self-nanoemulsion system is selected from one or more of ethanol, propylene glycol, n-propanol, isopropanol, n-butanol, isobutanol, n-pentanol, isopentanol, 1-hexanol, 2-hexanol, 1-octanol, 2-octanol, fusel oil, polyethylene glycol, dimethyl isosorbide, propylene carbonate, diethylene glycol monoethyl ether, tetrahydrofuran polyglycol ether and glycerol; the content of the co-emulsifier in the self-nanoemulsion system is 5-40% w / w; The solid adsorbent used in the self-nanoemulsion oral adhesive film preparation is various pharmaceutically acceptable solid adsorbents, selected from one or more of microcrystalline cellulose, lactose, pregelatinized starch, talcum powder, silicon dioxide, mannitol, PEG 4000 and PEG6000.

3. A self-nanoemulsion oral adhesive film preparation of asenapine maleate according to claim 2, characterized in that: The mass ratio of asenapine maleate, propylene glycol monocaprylate, polyoxyethylene (35) castor oil ELP and diethylene glycol monoethyl ether is 28:360:296:148; the formula of the asenapine maleate self-nanoemulsion oral adhesive film preparation is: The dosage of the asenapine maleate self-nanoemulsion oral adhesive film preparation is 2.5 mg / tablet.

4. The method for preparing the asenapine maleate self-nanoemulsion oral adhesive film preparation according to claim 1, characterized in that: Follow these steps: a. Mix the drug with the oil phase, emulsifier and co-emulsifier, and stir in a 37°C water bath to fully dissolve the drug to form an asenapine maleate self-nanoemulsion system; b. Dispersing the film-forming material and the adhesive material in water and stirring to dissolve to form a uniform film-forming glue; c. The asenapine maleate from step a is poured into the film-forming gel of step b under stirring at room temperature, and a solid adsorbent is added after forming a nanoemulsion, and stirred until uniformly dispersed to allow sufficient adsorption; d. Add taste masking agent and pigment, stir evenly at room temperature, let stand to degas, use a coating machine to spread the film, set the scraper height and coating speed, dry at 40°C after coating, wait for the temperature to return to room temperature, and demold to obtain the asenapine maleate self-nanoemulsion oral adhesive film preparation.

5. An asenapine maleate nanocrystal oral adhesive film preparation, characterized in that: The invention mainly consists of asenapine maleate nanosuspension, film-forming material, adhesive material, plasticizer and taste-masking agent; the asenapine maleate nanosuspension is prepared by wet grinding, and the nanosuspension is dispersed in film-forming glue to form a biological adhesive film; the nanoparticles formed by the preparation after redissolution have a particle size of 10 to 500 nm.

6. The asenapine maleate nanocrystalline oral adhesive film preparation according to claim 5, characterized in that: The nanosuspension is prepared from a drug and a stabilizer. The content of the nanosuspension in the asenapine maleate nanocrystal oral adhesive film preparation is 10-60% w / v, the particle size of the nanosuspension is 10-400 nm, and the concentration of asenapine maleate in the nanosuspension is 1-6% w / v; wherein the stabilizer is selected from one or two of Tween 20, Tween 80, poloxamer 188, hydroxypropyl methylcellulose, sodium lauryl sulfate, and polyethylene caprolactam-polyvinyl acetate-polyethylene glycol graft copolymer; the concentration of the stabilizer is 0.25-5% w / v; in the nanocrystal oral adhesive film preparation, the plasticizer is selected from any one of polyethylene glycol 400, glycerol, 1,2-propylene glycol, silicone oil, mannitol, and sorbitol, or a mixture of any two of them in any proportion.

7. The asenapine maleate self-nanoemulsion oral adhesive film preparation according to claim 1 or the asenapine maleate nanocrystal oral adhesive film preparation according to claim 5, characterized in that: The film-forming material used is a pharmaceutically acceptable polymer film-forming material, specifically selected from hydroxypropyl methylcellulose, hydroxypropyl cellulose, polyvinyl alcohol, hydroxypropyl methylcellulose, sodium carboxymethyl cellulose, polyvinyl pyrrolidone K90, polyvinyl alcohol-polyethylene glycol copolymer, xanthan gum, tragacanth gum, sodium alginate, pullulan or a combination thereof; the content of the film-forming material is 10-60% w / v; The adhesive material used is a pharmaceutically acceptable bioadhesive material, selected from one or two of sodium carboxymethylcellulose, carbomer, polycarbophil, chitosan, carrageenan, polyvinyl pyrrolidone K90, xanthan gum, gelatin, guar gum, gum arabic, polyacrylic acid, methyl methacrylate copolymer, copolymer of acrylic acid and alkyl acrylate, sodium hydroxypropyl methylcellulose, and hydroxypropyl methylcellulose; the content of the adhesive material is 1-20% w / v.

8. The oral adhesive film preparation of senapine maleate nanocrystals according to claim 5, characterized in that: The mass ratio of asenapine maleate and the stabilizer polyethylene caprolactam-polyvinyl acetate-polyethylene glycol graft copolymer is 360:60; the formula of the asenapine maleate nanocrystalline oral adhesive film preparation is: The dosage of the asenapine maleate nanocrystal oral adhesive film preparation is 2.5 mg / tablet.

9. The method for preparing the asenapine maleate nanocrystalline oral adhesive film preparation according to claim 5, characterized in that: Follow these steps: a. The drug, stabilizer, grinding medium and grinding beads were weighed according to the proportion of each prescription and placed in a grinding tube, mixed evenly to form a coarse suspension, and asenapine maleate nanosuspension was prepared by wet grinding; b. Dispersing the film-forming material and the adhesive material in water and stirring to dissolve to form a uniform film-forming glue; c. Pour the asenapine maleate nanosuspension of step a into the film-forming gel of step b under stirring at room temperature and stir evenly; d. Add plasticizer, taste masking agent and pigment, stir evenly at room temperature, let stand to degas, use a coating machine to spread the film, set the scraper height and coating speed, dry at 40°C after coating, wait for the temperature to return to room temperature, and demold to obtain the asenapine maleate nanocrystal oral adhesive film preparation.

10. Use of the asenapine maleate self-nanoemulsion oral adhesive film preparation according to claim 1 or the asenapine maleate nanocrystalline oral adhesive film preparation according to claim 5 in the treatment of acute schizophrenia in adults, acute mania and bipolar mania in children.

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