A Study of Mucoadhesive Bond Strength of Buccoadhesive Compacts for Systemic Drug Delivery: In-vitro/ In-vivo correlation

Compacts prepared from binary combinations of Carbopol^® 934 P (CP), Polycarbophil (Noveon^® AA1, PC) and Hydroxy propyl cellulose (Klucel^®, HPC) and coated on all but one flat surface with Poly Methyl Methacrylate - PMMA (chloroformic solution) were evaluated for mucoadhesive bond strength on a modified mucoadhesive bond strength apparatus using rabbit stomach mucosa (SM) and small intestine mucosa (SIM). In -vitro mucoadhesion tests indicated that the detachment force increased linearly with concentration of CP/PC in the compacts. Mucoadhesion of the compacts with SIM were higher when compared to SM. The compacts with higher proportions of CPIPC showed longer buccoadhesion time (time the compact remained in contact with the buccal mucosa) than HPC alone in humans. In-vivo buccoadhesevity of the coated compacts was studied in healthy human volunteers. An index was used to study the redness and ulceration of the contact buccal mucosa.

Compacts with higher proportions of CP/PC showed longer buccoadhesion time than HPC alone. Significant correlation coefficient (r) values (P<0.01) were obtained between in-vitro fracture strength of the compacts and in-vivo buccoadhesion time. Hence, the in-vitro mucoadhesive model developed by us provides useful information on the residence time of the compact for systemic drug delivery in the oral cavity, and compacts containing less than 50% of CP/PC were safer to use in humans.