In-vitro bioadhesion of carbopol hydrogels

The main goal of this work was to study the adhesive capacity of hydrogels obtained from carbopol, this was achieved using a tensile tester in which adhesion work was the main parameter. The intended use of these hydrogels was the buccal administration of propanolol HCl. The adhesion assays were carried out under two hydration conditions, in order to evaluate the influence of water on adhesion. Results showed that adhesion capacity was considerably increased when water was limited in the system. The influence exerted on adhesion work by the polymer molecular weight and the crosslinking percentage were also studied and results showed that an increase in either of the mentioned parameters gave rise to a decrease in adhesion. Finally, propranolol HCl was included into the hydrogels. It was observed that when water was limited in the system there was an increase in adhesion due to the increase in elasticity caused by the formation of a complex between the polymer and the drug. However, when there was no water limitation there was a slight decrease in adhesion caused by the precipitation of the complex carbopol-propranolol HCl.