Some formulation factors influencing the rate of drug release from bioadhesiw matrices

The development of monolithic matrices with controlled release and mucosa-adhesive properties was investigated. After an initial screening procedure for formulations that showed stability and minimal swelling, the rate of release of a model water soluble drug from various polyacrylic acid containing matrices was evaluated. All the formulations gave a prolonged drug release relative to a lactose containing control formulation. A formulation containing Carbopol 934P and CaCl2, was found to give the slowest rate of drug release (t50% of 7.77h), with release kinetics nearest to the ideal zero order. When tested in a modified tensiometer it was found that the inclusion of a relatively high loading of a model drug did not adversely affect the adhesive properties of these formulations.