42results about How to "Retain biocompatibility" patented technology

The invention relates to a preparation technique of crosslinked hyaluronic acid gel preparation, characterized in that divinylsulphone reacts with hydroxyl group of hyaluronic acid to form ether linkage. The steps are that the raw material of hyaluronic acid being put into container and dissolving in alkali reagent; stirring to make it thoroughly dissolve; mixing the alkaline hyaluronic acid solution and divinylsulphone in container to form crosslinked hyaluronic acid gel clot; adding substance riched in hydroxyl groups into the reaction solution; extracting the crosslinked hyaluronic acid gel clot and putting it into agitator to stir; and then crosslinked hyaluronic acid gel becoming micro grained. The advantages thereof are that the gel preparation is suitable for injection in vivo, with long residence timen in humans and good filling effect.

The invention relates to a bone repair material containing nano hydroxyapatite / collagen particles, and a preparation method thereof. The invention provides a bone repair material which comprises: 1 to 2 parts by weight of the nano hydroxyapatite / collagen particles, 1 part by weight of chitosan and 2 to 3 parts by weight of Beta-sodium glycerophosphate (which is supplemented by the weight proportion of the components). The invention also provides a preparation method of the bone repair material; the bone repair material is placed at 37 DEG C or injected into human body, thus forming in-situ gelatin. The bone repair material provided by the invention not only can retain the characteristics of modeled natural bone structure, but also ensures the new performance of syringeability of the material and has temperature sensitivity, thus being applicable to minimal invasive surgery and convenient for clinical application.

The invention relates to cross-linked sodium hyaluronate and a preparation method and application thereof. The cross-linked sodium hyaluronate is prepared from raw materials, including sodium hyaluronate, an inorganic salt and a cross-linking agent. The preparation method comprises the steps: dissolving a certain amount of sodium hyaluronate in an alkaline solution with the pH value of 7.5 to 9.0, then, adding a certain amount of inorganic salt into the solution, and carrying out stirring until the inorganic salt is completely dissolved; heating the solution to the temperature of 20 DEG C to 60 DEG C, then, slowly dripping a certain volume of cross-linking agent solution into the solution, carrying out stirring, and carrying out a reaction for a period of time while carrying out heat preservation; adjusting the pH to 7.1 to 7.5 with acid, carrying out balancing for 1 to 2 hours, then, carrying out precipitation with ethanol or an ethanol solution, so as to obtain lumpy solids, i.e., the cross-linked sodium hyaluronate. By the method provided by the invention, the cross-linking efficiency of the cross-linked sodium hyaluronate can be increased, the reaction yield can be increased, side reactions can be reduced, and the residual of the cross-linking agent can be reduced; the prepared cross-linked sodium hyaluronate is safe and non-toxic, is good in stability, long in in-vivo retention time and good in filling effect and is applicable to in-vivo injection.

An injectable pH-sensitive chitosan quaternary ammonium salt hydrogel is prepared through reaction between chitosan and 2.3-epoxypropyl ammonium trimethylchloride, depositing in acetone, washing, baking to obtain chitosan quatemary ammonium salt, dissolving it in acidic solution, dripping the solution of glycerine phosphate while stirring, and heating for gelatinizing.

The invention relates to a ligament support containing silk fibroin compound oriented nanofiber and a preparation method thereof, and belongs to the technical field of medical apparatus and instruments. The ligament support is prepared from oriented fiber combining silk fibroin with a medical high molecular synthetic material and has a porous three dimensional structure, the mass ratio of the silk fibroin and medical high molecular synthetic material in the compound oriented fiber is (1-20):(1-1), the diameter of the compound oriented fiber is 500nm-10000nm, the thickness of the ligament is 1mm-10mm, and the width of the ligament is 1mm-15mm. The ligament support has a uniform microstructure and good biocompatibility, provides a matrix structure for growing of ligament cells, and can be used for increasing the tensile strength of the ligament due to the compound fiber orientated structure. The ligament support is simple in preparation method and convenient to operate, the preparation process is controllable, and the preparation method is suitable for preparing the ligament supports of various sections and lengths.

The invention relates to a preparation method of an organic soluble photosensitive chitosan derivative. The method comprises the following steps that: 2g of chitosan is added into 70ml of triethylamine to be stirred at room temperature, so that the chitosan is uniformly dispersed in the triethylamine; the carbon tetrachloride solution of 10 weight percent of photosensitive chloride monomer is prepared, wherein the amount of the added photosensitive chloride monomer is 0.5 to 8 times of the mole of chitosan on the amino, imino and hydroxyl; chloride monomer solution is slowly dripped into chitosan solution, to be continuously stirred; after all the solution is dripped, the reaction is continued to be carried out for 2 to 6h; after the reaction, filtration is carried out, and powdery solid is prepared; and then 8 weight percent of sodium bicarbonate solution is washed by water for 3 times; the product washed by water is filtered, vacuumized and dried to prepare the chitosan derivative; and the derivative can be dissolved in acetone, toluene, N, N-dimethylformamide, benzene and other organic solutions. A post-processing purification process without toxic, harm or pollution is adopted in the preparation process, and the preparation method of the invention is an environmental-friendly process method.

The invention relates to a method for preparing a light sensitive type water soluble chitosan derivative. The method comprises the following steps of: adding chitosan into 2-weight percent dilute solution of acetic acid to prepare 2 weight percent aqueous solution of chitosan; adding a light sensitive acrylamide-type monomer of N-p-hydroxyphenyl acrylamide or N-[4-(sulfonamide)phenyl]acryloyl into ethanol to prepare ethanol solution of the light sensitive acrylamide-type monomer; mixing the2 weight percent aqueous solution of chitosan, and the ethanol solution of the light sensitive acrylamide-type monomer to obtain mixed solution; adding p-hydroxyanisole in to the mixed solution; heating the mixed solution to the temperature of between 50 and 70 DEG C for reaction, neutralizing the mixed solution by using sodium hydroxide and performing rotary evaporation, purifying and vacuum-drying to obtain the light sensitive type water soluble chitosan derivative. The method has the advantages of mild reaction conditions, easy control, simple steps, easily-controllable substitution degree, environmentally-friendly subsequent treatment and economical reaction process.

The invention relates to amphipathic chitosan-bile acid derivatives and a preparation method thereof. The amphipathic chitosan-bile acid derivatives have the structure shown as a general formula I; and in the formula, R1 refers to H or COCH3, R2 and R3 respectively refer to -H or -OH, and R4 refers to -CH2CHOHCH3. The preparation method comprises the following steps of: reacting chitosan with bile acid in the presence of activating reagents of EDC and NHS to obtain hydrophobic chitosan-bile acid; and reacting the hydrophobic chitosan-bile acid with epoxypropane under the alkaline condition toobtain the chitosan-bile acid derivatives with good water solubility. By the method, the amphipathic chitosan-bile acid derivatives with high surface activity, emulsifying property and hydrotropy canbe obtained, and can serve as medicine solubilizing and sustained-release carriers.

The invention discloses a composite collagen membrane for bone grafting in an alveolar bone defect area and a preparation method of the composite collagen membrane, the composite collagen membrane isof a double-layer structure and is composed of a compact collagen fiber membrane layer and a collagen sponge layer; wherein the collagen fiber membrane layer is made of bovine collagen fibers, and thecollagen sponge layer comprises bovine collagen fibers and hyaluronic acid. The compact layer can prevent non-osteoblasts from growing towards a bone grafting area, but allows fibroblasts to be attached along collagenous fibers; and a three-dimensional frame structure of the collagen sponge layer serving as the inner side is beneficial to osteoblast fusion and bone regeneration supporting. The composite collagen membrane has low antigenicity and excellent biocompatibility and has enough barrier time after being used for a human body, and the membrane can keep a complete structure in a wet state and achieve the effect of being attached to the bone wall; after the composite collagen membrane is used for about 1-2 months, the composite collagen membrane starts to be automatically degraded, and is finally decomposed into components which are non-toxic and harmless to a human body and are absorbed by tissues.

The invention discloses a hydrogen peroxide responding type targeted fluorescent medicine-carrying nanomaterial and a preparation method and belongs to the technical field of nanomaterials. A structural formula is shown in the description, and the preparation method of the nanomaterial includes the steps of synthesis of PHEMA, synthesis of FPEG, synthesis of PHEMA-Sim / Prv / Com / Lo, synthesis of PHEMA-Sim / Prv / Com / Lo-FPEG-ISO-1 and the like. The nanoparticles prepared by the preparation method have the functions of high drug utilization rate, fluorescence calibration and targeting of atherosclerotic plaques.

The invention discloses a carboxymethyl-polyaminated chitosan decolorant, and a preparation method and application thereof. The carboxymethyl-polyaminated chitosan decolorant is prepared from chitin through a carboxymethyl reaction, a deacetylation reaction and an addition reaction. The carboxymethyl-polyaminated chitosan decolorant prepared in the invention retains the inherent excellent properties of no toxicity, no harm, biocompatibility, degradability and the like of chitosan, is substantially improved in dissolving performance, especially has enhanced decoloring performance on dyes and has a wider application scope. The preparation method is short in production period and simple to operate. The carboxymethyl-polyaminated chitosan decolorant can be applied to wastewater treatment chemicals or as a high-efficiency decolorant and is an environment-friendly water treatment agent.

The invention discloses a chlorine dioxide stabilizing medium, a preparation method, and disinfecting liquid prepared from the chlorine dioxide stabilizing medium. The preparation method comprises the following steps of mixing mesoporous TiO2 capsules with isopropyl alcohol and gamma-aminopropyltriethoxysilane, performing a reflux reaction at 70-90 DEG C, and enabling obtained modified nanometer TiO2 capsules to be dispersed in an alkaline solution so as to obtain suspending liquid I; mixing chitosan with the isopropyl alcohol and glycidyltrimethylammonium chloride, performing a reflex reaction at 70-90 DEG C, performing extraction with anhydrous ethanol, performing drying, and enabling the obtained chitosan quaternary ammonium salt to dissolve in an alkaline solution so as to obtain a solution II; and mixing the suspending liquid I with the solution II so as to obtain the chlorine dioxide stabilizing medium. ClO2 is led into the chlorine dioxide stabilizing medium, and a reaction is performed, so that the disinfecting liquid is obtained. The disinfecting liquid is safe and non-toxic, and can rapidly remove microorganisms on the surfaces of fruits and vegetables for preservation of the fruits and the vegetables.

The invention discloses moisture preserving, whitening and freckle and pox removing anti-bacterial dressing, belongs to the technical field of biological materials and further discloses a preparing method of the moisture preserving, whitening and freckle and pox removing anti-bacterial dressing. The moisture preserving, whitening and freckle and pox removing anti-bacterial dressing is prepared from, by weight, 0.5-5% of bacterial cellulose, 2-8% of chitosan azelaic acid, 2.5-5% of hydroxypropyl methyl cellulose, 2-8% of glycerol, 0.5-2.5% of polyethylene glycol and the balance water. Chitosan azelaic acid and bacterial cellulose are combined and can restrain activity of melanin enzyme, eliminate acnes and play a role in whitening, freckle removing and moisture preserving. The technology is simple, no pollution is caused to the environment, the problem of insolubility and irritation of chitosan and azelaic acid which are individually used in medical instruments and cosmetics is solved, and the problems of non-dispersibility of bacterial cellulose in water and incompatibility of chitosan azelaic acid and hydroxypropyl methyl cellulose are solved.

The invention discloses a water-soluble dropping pill prepared by a crosslinking technology and a preparation method of the water-soluble dropping pill. The water-soluble dropping pill comprises an inner layer core liquid, a middle shell layer and an outer shell layer. The inner layer core liquid contains water and water-soluble essence, the middle shell layer is a polyelectrolyte composite gel layer formed by cross-linking reaction of sodium alginate, chitosan and calcium salt under an acidic condition, and the outer shell layer is a waterproof wax layer. The middle shell layer of the water-soluble dropping pill is the polyelectrolyte composite gel layer formed by the cross-linking reaction of the sodium alginate, the chitosan and the calcium salt under the acidic condition, and the polyelectrolyte composite gel layer has the characteristics of hardness and frangibility after being dried, so that the prepared water-soluble dropping pill is relatively good in roundness and has a certain hardness; when a consumer smokes the cigarette, the dropping pill is easily broken by pinching and has obvious blasting sound, so that the smoking requirement of the cigarette consumer can be met; the outer shell layer can prevent the middle shell layer from increasing the toughness due to water absorption, so that the weather resistance of the water-soluble dropping pill is improved, and the water-soluble dropping pill can maintain relatively stable hardness and brittleness.

The invention discloses a preparation method of a silk fibroin / silicon dioxide composite material. The preparation method comprises the following steps: (1) preparing silicon dioxide sol: mixing tetraethyl orthosilicate with water, adding a silk fibroin solution, adding ethanol, adjusting the pH value of the system to 2-3, performing heating to a temperature of 50-70 DEG C, and performing a stirring reaction to obtain the silicon dioxide sol; (2) preparing a composite solution: cooling the silicon dioxide sol prepared in the step (1) to room temperature, and adding the silk fibroin solution into the silicon dioxide sol while stirring to obtain a composite solution; (3) preparing gel: pouring the composite solution into a mold, and performing reacting at 30-50 DEG C for 1-20 hours to obtain the gel; and (4) purifying, aging, drying and dehydrating the gel in the step (3) to obtain the silk fibroin / silicon dioxide composite material. According to the preparation method of the silk fibroin / silicon dioxide composite material, the prepared SF / SiO2 composite material is excellent in mechanical property and good in biocompatibility.

The invention discloses a multifunctional liposome based on hydrogen peroxide response and a preparation method and application thereof, and belongs to the technical field of nano materials. The multifunctional liposome based on hydrogen peroxide response is jointly composed of phosphatidylserine and biblock polymer polyethylene glycol-polyacrylate propylene; and the preparation method includes the steps of preparation of PEG-PPS and preparation of the multifunctional liposome in response to hydrogen peroxide. The multifunctional liposome based on hydrogen peroxide response is used for coatinga dual-mode probe FITC-SiO2@Fe3O4 and can be used for in-vivo imaging; and the multifunctional liposome based on hydrogen peroxide response is used for coating anti-atherosclerosis drugs and can be used for drug release in vivo. According to the multifunctional liposome based on hydrogen peroxide response and the preparation method and application thereof, biodegradable polyethylene glycol is conjugated to the outer surface of the liposome to produce an invisible carrier, and immune clearance is prevented; and meanwhile, the traditional polyethylene glycol is specially modified, and while biocompatibility is retained and the hydrogen peroxide can be responded to release imaging agents or the drugs.

The invention belongs to the technical field of biological medicines and polymer nano-materials, and particularly relates to a pH-responsive drug-loaded nanoparticle and a preparation method thereof.According to the preparation method, a core layer with pH response is obtained through electrostatic interaction of a quaternary ammonium salt modified pectin / polycaprolactone grafted copolymer and drug adriamycin, and a disulfide crosslinked shell layer is obtained through mercaptopectin under the action of hydrogen peroxide, so that drug-loaded nanoparticles with pH response are prepared; a shell-core structure enables the nanoparticle to have high stability, leakage of the drug can be effectively reduced, long-acting release is achieved, the quaternary ammonium salt unit in the core is pH-sensitive, the nanoparticle is subjected to conformational change in the environment with low pH, active ingredients of the drug in the nanoparticle are released, and the drug has targeting property.

The invention discloses an antibacterial and healing-promoting functional dressing which comprises a bottom lining layer, a polyurethane foam layer and an antibacterial and healing-promoting functional layer which are sequentially bonded, the antibacterial and healing-promoting functional layer comprises, by mass, 0.03-20% of antibacterial and healing-promoting functional components, 0.03-20% of a humectant and 0.1-10% of a thickener, and the sum of the mass fractions of the antibacterial and healing-promoting functional components and the mass fractions of the humectant and the thickener is 100%. The antibacterial and healing-promoting functional component is composed of one or more water-soluble chitosan which is good in solubility, antibacterial and capable of promoting skin cell proliferation. A high polymer material with antibacterial and healing-promoting functions is mixed with a polymer with moisturizing and swelling characteristics, so that the antibacterial property and biocompatibility of the material are retained. The viscous functionalized polymer solution keeps the function of absorbing wound exudate while endowing the foam dressing with functionality; the wound exudate adsorbed by the dressing can also be used as a solvent, so that the dry antibacterial healing-promoting macromolecules are quickly swelled and dissolved to recover a semi-gel state, and a moist environment of the wound is stably and continuously kept.

The invention belongs to the field of materials, and particularly relates to a cellulose-based friction nano-generator and a preparation method thereof. The invention provides a cellulose-based nanometer friction generator, the friction generator comprises a positive electrode material, a negative electrode material and an electrode material, and the positive electrode material comprises bacterial cellulose and hydroxyethyl cellulose. The invention provides a cellulose-based positive electrode material for a friction nanometer generator for the first time, and also provides a method for improving the output performance of the friction nanometer generator by regulating and controlling the surface work function of a friction material through a simple physical blending method for the first time. The nano friction generator positive electrode film prepared by the invention is only dissolved by deionized water in the preparation process, and has good biocompatibility and degradability; the introduced hydroxyethyl cellulose can reduce the surface work function of the bacterial cellulose film, and the output performance of the prepared friction nano-generator can be greatly improved while the advantages of the bacterial cellulose are reserved.

The invention relates to cross-linked sodium hyaluronate and a preparation method and application thereof. The cross-linked sodium hyaluronate is prepared from raw materials, including sodium hyaluronate, an inorganic salt and a cross-linking agent. The preparation method comprises the steps: dissolving a certain amount of sodium hyaluronate in an alkaline solution with the pH value of 7.5 to 9.0, then, adding a certain amount of inorganic salt into the solution, and carrying out stirring until the inorganic salt is completely dissolved; heating the solution to the temperature of 20 DEG C to 60 DEG C, then, slowly dripping a certain volume of cross-linking agent solution into the solution, carrying out stirring, and carrying out a reaction for a period of time while carrying out heat preservation; adjusting the pH to 7.1 to 7.5 with acid, carrying out balancing for 1 to 2 hours, then, carrying out precipitation with ethanol or an ethanol solution, so as to obtain lumpy solids, i.e., the cross-linked sodium hyaluronate. By the method provided by the invention, the cross-linking efficiency of the cross-linked sodium hyaluronate can be increased, the reaction yield can be increased, side reactions can be reduced, and the residual of the cross-linking agent can be reduced; the prepared cross-linked sodium hyaluronate is safe and non-toxic, is good in stability, long in in-vivo retention time and good in filling effect and is applicable to in-vivo injection.

The invention relates to a method for preparing organic-dissolvable photosensitive chitosan derivate. The method includes the following steps that: 2g of chitosan is added in 70ml of triethylamine, and is stirred under the room temperature, so that the chitosan can be uniformly dispersed in the triethylamine; carbon tetrachloride with 10 percent by weight of photosensitive acyl chloride monomer is prepared, wherein the amount of the added photosensitive acyl chloride monomer is 0.5 to 8 times larger than the mole number of amino group, imino group and hydroxyl group on the chitosan; the acyl chloride monomer solution is slowly dripped into the chitosan solution, and is constantly stirred; after all the acyl chloride monomer solution is dripped, reaction continuously takes place for 2 to 6 hours, vacuum filtration is carried out after the reaction is finished, so that powder-like solid is obtained, the powder-like solid is then washed by water with 8 percent by weight of sodium bicarbonate solution for three times, the product is filtered after washing, and is dried under vacuum, so that the chitosan derivate is obtained, and the chitosan derivate can be dissolved in organic solution such as acetone, methylbenzene, N,N-dimethylformamide and benzene. A non-toxic, harmless and pollution-free post-purification step is adopted in the preparation process, so the method is an environment-friendly technique.

The invention discloses a photopolymerizable chitosan derivative. The derivative is prepared by adding an activated mixed solution of methacrylamide carboxylic acid or acrylamide carboxylic acid, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS) into an acetic acid solution of chitosan dropwise, reacting at room temperature, regulating the pH value to 8, dialyzing with deionized water and lyophilizing. The derivative remains the original bioactivity and biocompatibility of chitosan, and introduces a new photopolymerizable group, can be polymerized through initiation of an initiator 2959 under ultraviolet radiation, and has the advantages of mild reaction condition, simple steps, easiness for control and environmentally-friendly post-treatment; and the prepared hydrogel has the advantages of low toxicity and excellent biocompatibility.

The invention discloses a preparation method of an implantable stent capable of inducing metastasis of circulating tumor cells. Specifically, the preparation method comprises the following steps: spin-coating PDMS, so that a thin film is formed, and curing the thin film; conducting plasma treatment on the obtained PDMS film, so that the surface of the PDMS film is negatively charged; dropping a cationic polymer solution onto the surface of the PDMS film, implementing spin-coating, then dropping clean water and implementing spin-coating, then spraying a PBS solution containing an exosome, thendropping an anionic polymer solution, implementing spin-coating, then dropping clean water and implementing spin-coating, therefore through such circulation, a layer-by-layer self-assembled film containing the exosome is loaded on the PDMS surface; and removing the PDMS from a substrate, and implementing disinfecting via epoxy hexane gas. The implantable stent provided by the invention, as a flexible thin film, is excellent in denaturation capacity and mechanical performance, and implanting difficulty, caused by space limitation, can be overcome; and the PDMS is modified via a layer-by-layer self-assembling technology, so that biocompatibility, non-degradability and excellent deformation capacity and mechanical performance are reserved, and meanwhile, loading and sustained release of the exosome / drugs are achieved.

The invention discloses a carboxymethyl-polyaminated chitosan decolorant, and a preparation method and application thereof. The carboxymethyl-polyaminated chitosan decolorant is prepared from chitin through a carboxymethyl reaction, a deacetylation reaction and an addition reaction. The carboxymethyl-polyaminated chitosan decolorant prepared in the invention retains the inherent excellent properties of no toxicity, no harm, biocompatibility, degradability and the like of chitosan, is substantially improved in dissolving performance, especially has enhanced decoloring performance on dyes and has a wider application scope. The preparation method is short in production period and simple to operate. The carboxymethyl-polyaminated chitosan decolorant can be applied to wastewater treatment chemicals or as a high-efficiency decolorant and is an environment-friendly water treatment agent.

The invention discloses a polymerizable chitosan derivative and a preparation method thereof. According to the invention, benzaldehyde is used for protecting the amino group of 2-amino-4-pentenoic acid, and the material is subjected to a reaction with the amino group on chitosan; when the reaction is finished, hydrochloric acid is used for deprotection, such that the polymerizable chitosan derivative is prepared. According to the invention, a double bond group which can be subjected to further polymerization reaction is introduced into chitosan molecular chain, such that the original biological activity and biocompatibility of chitosan are maintained in the obtained polymerizable chitosan derivative. During the preparation process, reaction conditions are mild, and the process is easy to control. According to the invention, a new chitosan derivative is provided, and chitosan modification range is expanded.

The present invention discloses an injectable pH-sensitive chitosan quaternary ammonium salt hydrogel and a preparation method thereof, belonging to the medicine engineering pharmaceutic preparation field. The method adopts the chitosan hyamine and the glycerophosphate to prepare the injectable pH-sensitive chitosan quaternary ammonium salt hydrogel. The preparation method comprises the following steps: (1) the chitosan and the 2.3-epoxypropyl ammonium trimethylchloride are reacted at the reaction temperature, are deposited using acetone, washed, and dried to obtain chitosan hyamine; (2) the prepared chitosan hyamine is dissolved into an acid solution; (3) glycerophosphate is added dropwise into the chitosan hyamine acid solution to obtain uniform and clear mixed solution while stirring; (4) the temperature is rised to a gelatinization temperature, and an uniform and transparent chitosan hyamine hydrogel is obtained after keeping constant temperature. The hydrogel can happen gelatinization at a room temperature, and responds to the internal pH value variation to swelling, dissolve and realize intelligent release of the embedding drugs.

The invention discloses a moisturizing, whitening, freckle-removing, acne-removing and antibacterial dressing, which belongs to the technical field of biomaterials and is composed of the following components by weight: bacterial cellulose: 0.5-5%, chitosan azelaic acid: 2-8% , hydroxypropyl methylcellulose: 2.5-5%, glycerin: 2-8%, polyethylene glycol: 0.5-2.5%, and the balance is water. The invention also discloses a preparation method of a moisturizing, whitening, freckle-removing, acne-removing and antibacterial dressing. The invention utilizes the combination of chitosan azelaic acid and bacterial cellulose to inhibit the activity of melanase, eliminate acne, and play the roles of whitening, freckle removing and moisturizing. The invention has simple process, does not pollute the environment, overcomes the insolubility and irritation of chitosan and azelaic acid used alone in medical equipment and cosmetics, and solves the non-dispersibility of bacterial cellulose in water and the resistance of chitosan Incompatibility of azelaic acid with hydroxypropylmethylcellulose.