Preparation of clindamycin-loaded PLGA microspheres and evaluation on its in vitro antibacterial activity

Objective To prepare the clindamycin-loaded sustained release microspheres with poly(lactic-co-glycolic acid)(PLGA)which have good biodegradability,and to investigate its related properties.Methods The clindamycin-loaded PLGA microsheres were prepared by emulsion-solvent evaporation method.Then the morphology and particle size distribution of clindamylin-PLGA microsheres were detected.And two factors affecting entrapment rate of microspheres,including the rate of PLGA/dichloromethane(P/D)and PLGA/clindamycin(P/C),were investigated.In addition,the clindamycin-PLGA was dispersed in dissolve medium and oscillated at37℃.Then the solution at different time was taken.Kirby-Bauer method was used to observe the ability of bacteriostasis by measuring the bacteriostatic ring size at different time.Results The acquired PLGA microspheres containing drugs exhibited well-defined properties,with the even and uniform sphere in appearance,general particles without adhesion,at the mean diameter of 700 nm mostly.The optimal ratio of P/D was 80/1and P/C was 5/1,and the entrapment rate obtained was 45.02%.Moreover the antibacterial effect was very obvious on the initial release,followed by aprolonged release from days 3to 19.The minimum inhibitory concentration(MIC)was reached on day 20.Conclusion Clindamycin-PLGA microspheres with good morphology and high encapsulation efficiency can be obtained using optimized formulation.The microspheres have a good antimicrobial effect in vivo through a long period of sustained release of drugs.