Preparation and characterization of poly (lactic-co-glycolic acid) microspheres containing RGD-hirudin / 复旦学报（医学版）

ABSTRACT

Purpose The main purposes of our research were to: 1. set up the method of the RGDHirudin microsphere preparation; 2. set up the method to test the activity and the content of the medicine contained in the microsphere; 3. analyse the key factors on the quality of the microsphere preparation. Methods Co-poly lactic acid glycolic acid (PLGA) microsphere was prepared by a modified solvent evaporation method by a double emulsion with the use of polyvinylalcohol (PVA) as emulsification; PLGA was used as biodegradable material and dichloromethane as organic solvent. The influence of formulation factors including the W1/O on microsphere diameter distribution and yield coefficient;PVA concentration on microsphere appearance, encapsulation and yield coefficient; ultrasound on spherulization average and medicine activity; stirring speed on spherulization average and microsphere appearance; PLGA on microsphere appearance and microsphere dispersity; concentration of NaCl on encapsulation efficiency, yield coefficient and medicine content etc were studied. Results The size of all the fabricated microsphere was measured according to the several factors that affect the particle size. The average diameter was 81.38 μm, which is good for further research. The medicine content and the percent yield of all the microsphere was high, which ranged from 83. 92% - 96. 3% and 79.93% - 95.05% respectively. The encapsulation efficiency was about 23.95% - 65. 13%. We found that the concentration of the NaCl and PVA were the very important factors to the encapsulation efficiency. Physiological activity of RGD-Hirudin containing in the microsphere and the release rate of the microsphere were controlled. Furthermore, the release rate was stable. Conclusions The physiologic activity of RGD-Hirudin released from the microspheres was stable. PLGA-RGD-Hirudin microspheres were controlled released by the in vitro studies. Therefore, the in vivo experiment was well grounded.