| Currently, the clinical application of peptide and protein drugs are still limited to the injection, which gives patient great pain and inconvenience. Therefore, the development of the non-injection mode to delivery protein and peptide has been a studied target for decades. And oral administration is of particular concern because of its safety, simple and convenience, and good patient compliance. Collagen peptide is relatively small molec ular weight peptide from the hydrolysis of collagen. Collagen peptide has various effects such as anti-oxidation, skin care, bone health and so on. But it has low bioavailability because collagen peptide is unstable and easily to be degraded by acids and enzymes in the gastrointestinal tract. Considering these issues, the oral enteric calcium alginate/chitosa n(SA/CTS) microspheres will be prepared to load collagen peptide in this article, and then to protect the stability of collagen peptide and improve it oral absorption by improving the intestinal adhesion of microspheres, and to improve its oral bioavailability. The main contents of this thesis are as follows:(1) Collagen peptide-loaded SA/CTS microspheres were prepared respectively by Double-Emulsion method and Spray Coacervation method, optimized and characterized. As a result, the microspheres prepared by Double-Emulsion method were with ideal sphericit y and small particle size and uniform distribution. The calcium alginate microspheres(SA microspheres) median particle size was 3.5 μm, SA / CTS microspheres was 4.5 μm. The SA / CTS microspheres prepared by Spray Coacervation Method was with poor sphericit y and large particle size as the median particle size was 162.8 μm, and these microspheres were separated into two kinds of less than 200 μm and range from 200 to 500 μm through sieve. The Drug-loading of SA microspheres and SA/CTS microspheres prepared by Double-Emulsion method was 7.83% and 4.50%, and The Drug-loading of 200 μm and 500 μm SA / CTS microspheres is 5.33% and 6.40%. In vitro release studies indicated that SA / CTS microspheres prepared by Spray Coacervation method completely released after 3 h in simulated intestinal fluid. Release of the microspheres prepared by Double-Emuls io n method was relatively moderate, about 70% of collagen peptide was released from SA / CTS microspheres after 3 h, and the thorough release takes about 8 h.(2) Everted Gut Sac(EGS) and Single-pass intestinal perfusion(SPIP) were used to study the Intestinal absorption of collagen peptide-loaded microspheres. The results proved that SA/CTS microspheres could significantly improve the intestinal absorption of collagen peptide, and the absorption was related to particle size of microspheres. The cumula t ive transmittance of different particle size of SA/CTS microspheres in EGS experiments was 500μm microspheres<200μm microspheres<10μm microspheres microspheres. Compared with 10 μm SA microspheres, the cumulative transmittance(Qn), the absorption rate constant(Ka) and the permeability coefficient(Peff) in the small intestine segments of 10 μm SA / CTS microspheres were significantly increased(p <0.05), which proved Chitosan is beneficial to the absorption of collagen peptide in small intestine segments.(3) Efficacy evaluation experiments showed that the collagen peptide-loaded microspheres were biological safety. High-dose collagen peptides microspheres group significantly improved the content of serum hyaluronic acid compared with control group(P <0.01).The result of skin biochemical indices test showed Non-significant differe nces between each group of mice administered and control group(P> 0.05) due to the short administration duration(28 days). The general and collagen morphology of skin tissue observation showed that each group administered improved the skin collagen fiber layer, showing the skin care effect of collagen peptide. |
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