STUDIES ON DESIGN OF BIOADHESIVE PELLETS USING SYNTHETIC AND NATURAL POLYMERS, AND THEIR INFLUENCE ON BIOADHESIVE STRENGTH AND DURATION
Duration of bioadhesion of pellets of different polymers was studied by the modified assembly and compared with the bioadhesive strength. Different hardness of bioadhesive pellets were prepared by various grades of copolymers of sodium acrylate and acrylamide (PAM 5110, PAA 1115, PAA 1118 and PAA 2131), cellulose derivatives (HPMC K100 and HPC) and natural polymers (sodium alginate and pectin) using wet granulation technique and evaluate their bioadhesive strength and duration. It was observed that the bioadhesion joint failure was due to the excessive hydration of polymers which forms the mucilage and provides the slippery surface causing detachment of pellets from the mucosal surface. The duration of bioadhesion was found to be dependent on the compactness or hardness of pellets as well as on molecular weight and hydrophilicity of polymers. Polyacrylamide pellets (PAM 5110) showed longer duration of adhesion as compared to the other copolymers of acrylic acid, cellulose derivatives and natural polymers. The duration of bioadhesion further increases with the increase of hardness of pellets; however the change in hardness failed to show any significant affect on bioadhesive strength.