A preliminary study for the development and optimization by experimental design of an in vitro method for prediction of drug buccal absorption.

The work was aimed at developing an in vitro method able to provide rapid and reliable evaluation of drug absorption through buccal mucosa. Absorption simulator apparatus endowed with an artificial membrane was purposely developed by experimental design. The apparent permeation coefficient (Papp ) through excised porcine buccal mucosa of naproxen, selected as model drug, was the target value to obtain with the artificial membrane. The multivariate approach enabled systematic evaluation of the effect on the response (Papp ) of simultaneous variations of the variables (kind of lipid components for support impregnation and relative amounts). A screening phase followed by a response-surface study allowed optimization of the lipid-mixture composition to obtain the desired Papp value, and definition of a design space where all mixture components combinations fulfilled the desired target at a fixed probability level. The method offers a useful tool for a quick screening in the early stages of drug discovery and/or in preformulation studies, improving efficiency and chance of success in the development of buccal delivery systems. Further studies with other model drugs are planned to confirm the buccal absorption predictive capacity of the developed membrane.