Studies on the Properties of Chitosan-Starch Beads and their Application as Drug Release Materials

Abstract

In this work, chitosan and blends of chitosan-starch beads were prepared and crosslinked with glutaraldehyde (pentane-1,5-dial). The blends were prepared with 1:1, 2:1 and 3:1 chitosan-starch ratios. Metformin hydrochloride (N,N-dimethylimidodicarbonimidic diamide hydrochloride), a type 2 diabetis drug, was incorporated into them. The materials were subjected to swellability tests and the effects of time and pH were established. Fourier Transformed Infrared Spectrophotometeric (FTIR) analysis was also carried out on the materials and their potentials as drug release systems studied. The results obtained from the FTIR studies showed that the uncrosslinked chitosan-starch bead showed O-H stretching band at 3424cm^-1 and N-H band at 1640cm^-1. The chitosan-starch bead also showed a band at 597cm^-1 corresponding to C-Cl band, due to the presence of metformin hydrochloride in the bead and its O-H stretching band was very strong and broad due to the numerous –OH groups in starch and chitosan. The results of swelling studies showed that the percent swellability of the polymer matrices increased in both the crosslinked and uncrosslinked beads as the amount of starch in them increased. The uncrosslinked chitosan beads had maximum swelling of 83.74%, while its crosslinked analogue had 47.93% in acidic medium (pH 2.06) within the range of test period of 60 minutes. The amount of drug released by the 1:1, 2:1 and 3:1 crosslinked chitosan-starch beads (13.90, 13.60, and 12.30mg/L, respectively) was much lower than that of their uncrosslinked analogues (22.50, 20.90, and 16.60mg/L, respectively) after 120 minutes, suggesting that the release of drug is delayed by crosslinking. This suggests that the crosslinked chitosan-starch beads can be used for regulating release of drugs in solid dosages such as beads or tablets.

Keywords: chitosan, chitosan-starch beads, drug release, metformin hydrochloride, swelling