FORMULATION OF CHITOSAN MICROSPHERES COVALENTLY ATTACHED WITH GALLIC ACID FOR DELIVERY IN ACIDIC ENVIRONMENT

Neeraj Kirar* and Bharat Kumar Tyagi

ABSTRACT

Microspheres of chitosan covalently attached with gallic acid were prepared using glutaraldehyde as the crosslinking agent and esterification as the process of attachment of gallic acid to chitosan surface. The formulated micropsheres were characterized for yield, particles size, micromeritic properties (angle of repose, bulk density, tapped density, Hausner’s ratio, Carr’s index), and in vitro drug release in various pH solutions (pH 1, 3, 4.5 and 6.5). The mean particle size of chitosan microspheres ranged from 46.147 ± 24.36 to 60.065 ± 21.72 μm while the size increased on attachment of gallic acid to be ranging from 57.867 ± 27.50 to 71.785 ± 17.07 μm. The percentage yield of different formulations was in the range 64.73 ± 0.6027 to 82.36 ± 0.4509 %. All the formulated microspheres exhibit good flow properties with a value of angle of repose between 26°18’ to 29°53’. The Carr’s index of all the formulations was found in the range 14.03 to 19.95 % indicating good flow ability. The Hausner’s ratio of the formulations was found in the range 1.16 to 1.25. The highest amount of drug was released at pH 3 (79.4%) after 40 min of incubation while the lowest amount of drug was released at pH 6.5 (7.0%).

Keywords: Gallic acid, Chitosan, Covalent linkage, Esterification, Antioxidant.