Abstract

The aim of this study was to investigate extrusion-spheronization pelletization for preparing pH-sensitive pellets
for colon-specific drug delivery. Polyacrylamide-grafted-guar gum (pAAm-g-GG) was prepared by taking three
different ratios of guar gum to acrylamide. Amide groups of these grafted copolymers were converted into
carboxylic functional groups. Fourier transform infrared (FTIR) spectroscopy and differential scanning
calorimetry were used to characterize copolymers. Pellets were prepared by incorporating an antidiabetic drug
viz., Glimepiride. In-vitro drug release was carried out in simulated gastric and intestinal conditions. The
effects of three independent variables (Microcrystalline cellulose, Polyacrylamide-grafted-guar gum (pAAm-g-
GG) and Wetting agent) on pellet size, friability, and drug release were studied with 23 factorial design. In vitro
drug release profile indicated an increase in drug release retardation with increasing pAAm-g-GG
concentration. The formulated pellets were stable with respect to their physicochemical characters and drug
content over a period of 60 days at different temperatures and relative humidity.