AN INVITRO ASSESSMENT OF SOME MUCOSA-ADHESIVE DOSAGE FORMS

An in vitro method was developed for the assessment of the adhesive force (i.e. the force required to break an adhesive bond) between a disc of test material and a model mucous membrane. This system showed reasonable reproductibility and produced data in agreement with previous studies. Some factors influencing the adhesive force were assessed and only increasing the rate of application of the tensile force was found to have a significant effect. Some putative mucosa-adhesive formulations were evaluated and some buccal tablets found to have minimal adhesive properties. It was concluded that only a small force is required to retain a dosage form within the buccal cavity. The stability of the adhesive bond was assessed for the two most adhesive materials (the poly(acrylic acids) Carbopol 934P and EX55) by subjecting to a continuous stress for 8 h prior to measuring the adhesive force. The Carbopol EX55 (polycarbophil) formed the most stable adhesive bond which remained intact for 8 h.