Acta Pharm. 55 (2005) 57-67

Preparation of gelatin microspheres containing lactic acid - Effect of cross-linking on drug release

RASSOUL DINARVAND^1*, SANAZ MAHMOODI², EFFAT FARBOUD², MASSOUD SALEHI¹ and  FATEMEH ATYABI²

dinarvand@tums.ac.ir

¹Faculty of Public Health, Tehran University of Medical Sciences, Tehran 14174, Iran
²Department of Pharmaceutics, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran PO Box 14155-6451, Iran

In this study, gelatin microspheres containing lactic acid were prepared by the polymerization technique using glutaraldehyde as the cross-linking agent. Dried microspheres were loaded by immersing them in an aqueous solution of lactic acid. In order to prepare microspheres with an appropriate drug release profile, the effect of time of cross-linking and the amount of cross-linking agent on the swelling properties of microspheres and their release profile were investigated. The microencapsulation efficiency, microspheres appearance, particle size, swelling ratio and drug release profile were also studied. Microspheres prepared with a larger amount of crosslinking agent, or after longer crosslinking time, showed a reduced swelling ratio in aqueous media. In vitro release pattern of lactic acid from gelatin microspheres showed a biphasic profile and the release rates were reduced upon increasing the amount of cross-liking agent and prolonging the cross-linking time.

Keywords: lactic acid, microspheres, gelatin, cross-linking