Physico-chemical and bioadhesive properties of polyacrylic acid polymers.

In this study, influence of several physico-chemical properties of bioadhesive polyacrylic acid poylmers (Carbopol 910, Polycarbophil, Carbopol 940 and Carbopol 934 PH) are investigated. The effect of pH on the swelling of polyacrylic acid polymers was studied at constant temperature, ionic strength and osmolality. The polymers showed the pH dependence of equilibrium swelling. The bioadhesive strength of the bond formed between surface-preswollen systems and the sublingual bovine mucus was determined by tensile experiments. It was found that the least substituted polymers Polycarbophil and Carbopol 910 with low molecular weight showed the same degree of bioadhesion while highly branched polyacrylic acid polymers Carbopol 940 and 934 PH showed reduced bioadhesion.