Factors affecting in vitro gastric mucoadhesion .4. Influence of tablet excipients, surfactants and salts on the observed mucoadhesion of polymers

The influence of a range of commonly used tabletting excipients, and other materials, on the observed mucoadhesion of Carbopol(R) 934P and in some cases, xanthan gum, has been tested. It is found that the hydrophobic: lubricant magnesium stearate has the ability, at 5% concentration, to hinder the formation of a strong mucoadhesive bond between both of the mucoadhesive polymers and the pig gastric mucosae. However, other commonly used flow aids and lubricant did not share this property. A number of cyclodextrins are demonstrated, al 5% concentration, to have no significant influence on mucoadhesion. Tablet diluents, however, do appear to have a significant influence on the observed mucoadhesion in this system. The effect of a range of. surfactants, non-ionic, cationic and anionic, on mucoadhesion is quantified, as is the influence of some salts and a chelating agent. It is concluded that the addition of additives to gastric mucoadhesive formulations can crucially influence the ability of the dosage form to bind to the porcine stomach in this test system. (C) 1997 Elsevier Science B.V.