Preparation and in vitro release of recombinant peptide-PLGA sustained release microspheres / 中国药学杂志

ABSTRACT

OBJECTIVE: To prepare recombinant peptide(rAHP, amino acid sequence is VLPVPR) PLGA sustained release microspheres by double emulsion solvent evaporation method. METHODS: The rAHP-PLGA microspheres preparation process was optimized by orthogonal experiments using PLGA copolymers with different LA/GA ratios or different molecular weights as sustained material, and in vitro drug release profiles of the microspheres were also investigated. RESULTS: The microspheres were smaller (P < 0.05) and more porous with lower molecular weight of PLGA. The optimal preparation process of rAHP-PLGA microspheres was as follows; PLGA concentration was 12 g · 100 mL-1, the stirring rate of the first emulsion was 1000 r · min-1, the volume ratio of inner water phase to oil phase was 1-7.5, and the PVA concentration was 4 g · 100 mL-1. The encapsulation efficiency of the rAHP-PLGA microspheres prepared by the optimum process was more than 90%, the drug loading was above 11% and the average particle diameter-was in the range of 70-90 μn. The cumulative in vitro release percentage in PBS buffer was less than 40% within 2 h, the release speed increased(P < 0.05) with lower molecular weight or lower ratio of LA/GA. The drug release curve was fit to Higuchi equation, suggesting that rAHP released from the microspheres based on diffusion mechanism. CONCLUSION: The rAHP-PLGA microspheres can be prepared easily with good morphology, high entrapment efficiency and certain sustained release capacity.