LAUSR

Chitosan microparticles were obtained by emulsion cross-linking technique. Impact of the carbon chain length of dicarboxylic acids (malonic, succinic, glutaric, adipic, pimelic, suberic, and azelaic) as cross-linking agents on morphology, encapsulation, and release of bovine serum albumin (BSA) was studied. Role of the polyglycerol polyricinoleate as surfactant to stabilize the pre-emulsions and its influence on the structure of the particles obtained was considered. The increase in the carbon chain length of dicarboxylic acids gives rise of the mass-average diameter of the microparticles. The greatest encapsulation ability of the cross-linked samples is observed for pimelic and suberic acids. The BSA encapsulation for azelaic acid decreases with the increase in the carbon chain length. The ratios of the initial and total cumulative releases of BSA for 24 h increase with the increase of the number of carbon atoms in dicarboxylic acid from 3 to 7. Beginning with the sample of cross-linked suberic acid, the dramatic decrease in the percentage of the initial release of BSA is occurred. The same dependence is observed for the swelling ratio due to the increase in the hydrophobic interactions within chitosan matrix and the growth of the thickness of dicarboxylic acid-polyelectrolyte layers on the surface of the microparticles. The carbon chain length of the above dicarboxylic acids was concluded to be available mode to control the properties of chitosan microparticles as vehicles for drug delivery and drug release.