Preparation of Poly(D,L-lactide-co-glycolide) Microspheres Containing Growth Hormone Release Peptide-6 and Effects on Animal Growth

Sustained-release GHRP-6 microspheres were prepared by double emulsion-in liquid evaporation process,using biodegradable polylactic-co-glycolicacid as carrier and the drug release test of the microspheres was detected in vitro. The microspheres with good yield,suitable sized and satisfied drug loading was obtained,and significant GHRP-6 sustained was shown in the test of drug release in vitro. The entrapment efficiency was 100%,mean particle size 3.45 μm and the yield above 79%.In pH7.0 physiological isotonic buffer solution,after 19.19% of GHRP-6 was released first day,the microspheres released at rate of 3.23% per day for more than 25 d(r=0.877).After 30 days,accumulative increased body weights on the group injected with GHRP-6 microspheres was significantly higher 22.56%(P0.05) and 53.71%(P0.01) than those group injected with GHRP-6 and saline respectively;The conclusion is that the sustained-release GHRP-6 microspheres has been developed successfully as a new long acting GHRP-6 formulation.