Colorimetric polymer films for predicting lipid interactions and percutaneous adsorption of pharmaceutical formulations.

摘要

PURPOSE: To develop and demonstrate a rapid and simple colorimetric film assay for evaluating lipid interactions of pharmaceutical compounds and gel formulations. METHODS: The colorimetric assay comprises glass-supported films of phospholipids and polydiacetylene, which undergo visible and quantifiable blue-red transformations induced by interactions with amphiphilic molecules applied in very small volumes on the film surface. The color transitions are recorded by scanning of the films, and quantified through a simple image analysis algorithm. RESULTS: We show that pharmaceutical molecules and gel formulations induce blue-red transformations after short incubation with the lipid/polydiacetylene (PDA) films. Colorimetric dose-response curves exhibit dependence upon the lipid affinity and extent of membrane binding of the pharmaceutical compounds examined. The colorimetric lipid/PDA film assay was employed for distinguishing the contributions of individual molecular components within gel formulations. CONCLUSIONS: The colorimetric data yield insight into the degree of lipid binding of the molecules tested. The film assay is particularly advantageous for analysis of semi-solid (gel or lotion) formulations, elucidating the lipid interaction characteristics of specific molecular components within the mixtures. The new colorimetric film assay constitutes a generic, rapid, and easily applicable platform for predicting and screening interactions of pharmaceutical compounds and complex formulations with lipid barriers.