Preparation And Research Of Insulin/Chitosan Microspheres

Chitosan as a natural polymer material, it was non-toxic and has good adsorption, biocompatibility, biodegradation, film-forming property,hydrophilicity and good modification. Genipin is an excellent natural biological crosslinking agent, which can dissolve in water and react with the amino group of chitosan. Insulin is a protein and peptide drugs, which have certain biological activity. Insulin is one of the most effective treatment of type I diabetes and type II diabetes drugs. The new insulin dosage form is a hot research topic. By oral administration, the area of drug absorption is big, the process of drug absorption is more close to the normal physiological cycle of the human body, infection and subcutaneous fat atrophy and other side-effects cannot occur. This way is the most easily acceptable to patients, but the direct oral insulin will be degraded by the pepsin and trypsin in gastrointestinal so that reduce the bioavailability of the drug.In this paper, through the emulsion chemical crosslinking method, using chitosan as the carrier and genipin cross-linking agent, chitosan microspheres with insulin were prepared. The optimum technological conditions of the slow release system were determined. The 1g chitosan solution was dissolved in 100 m L acetic acid solution, and the concentration of acetic acid solution was 2 %.Then chitosan solution, 30 mg insulin and Span-80 2 m L were added to 100 m L liquid paraffin. 0.02 g genipin was added to the mixture one hour after. The reaction was reacted 3 h at the conditions of 40 degree centigrade and stirring speed under of 800 r/min. Through Infrared spectroscopy(IR), scanning electron microscope(SEM), ultraviolet spectrophotometer(UV/vis) and other test methods,this paper has discuss the impact of the different dosage of crosslinking agent,crosslinking time, chitosan/insulin ratio, stirring speed, dosage of emulsifying agent, emulsifying time on the morphology of chitosan microspheres, drugloading ratio and the embedding rate for drug. At the same time under the different conditions of insulin release time and release rate were characterized.Chitosan sustained release microspheres with an average particle size of 15?m and a drug loading of 1.18 %. The release of insulin was only 36 % after 2 h,which avoided the emergence of burst release. The release of insulin reached73 % after 12 h, then the release of insulin gradually leveled off. The release rate of insulin was 85 % after 48 h. That reached the purpose of insulin protecting and releasing.