FACTORS AFFECTING IN-VITRO GASTRIC MUCOADHESION .1. TEST CONDITIONS AND INSTRUMENTAL PARAMETERS

A new method to test the in vitro gastric mucoadhesion of polymers has been developed. In order to validate the testing system, and to investigate its compatibility with previously published results, experiments have been undertaken to elucidate which test conditions and instrumental parameters influence the observed results. It was found that the region of pig stomach chosen influenced the observed mucoadhesion, in terms of the work of adhesion, and the results correlated with the amount of mucus on the tissue, as found by alcian blue staining. It was subsequently found that the contact time and force between tissue and mucoadhesive polymer, the speed of removal of the test probe and degree of prehydration of the polymer tablet significantly affected the results obtained. Although some of the parameters which constitute a mucoadhesive test method have been studied none is the subject of a universal standard which all experimenters utilize. The influence of the composition of the test medium in which the experiments are carried out, in terms of pH and sodium chloride content, is also assessed for to assess any possible influence on the strength of the observed mucoadhesive bond. It is found that a wide range of factors, not standardized in previous mucoadhesive testing systems, can crucially influence the strength of the observed mucoadhesive bond.