title: Colorimetric polymer films for predicting lipid interactions and percutaneous adsorption of pharmaceutical formulations.
abstract: OBJECTIVE
  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.
authors.affiliation: Department of Chemistry and Ilse Katz Institute for Nanotechnology, Ben Gurion University of the Negev, Beersheba, Israel.
authors.forename: Izek
authors.initials: I
authors.lastname: Ben-Shlush
authors.forename: Roman
authors.initials: R
authors.lastname: Volinsky
authors.forename: Marina
authors.initials: M
authors.lastname: Katz
authors.forename: Yogesh
authors.initials: Y
authors.lastname: Scindia
authors.forename: Racheli
authors.initials: R
authors.lastname: Itzhak
authors.forename: Hila Tsahor
authors.initials: HT
authors.lastname: Ohayon
authors.forename: Ido
authors.initials: I
authors.lastname: Yosha
authors.forename: Raz
authors.initials: R
authors.lastname: Jelinek
mesh_terms: D000327:Adsorption; D002626:Chemistry, Pharmaceutical; D003124:Colorimetry; D005782:Gels; D008055:Lipids / Q000737:chemistry*; D000078789:Polyacetylene Polymer; D011108:Polymers / Q000737:chemistry*; D053279:Polyynes / Q000737:chemistry*; D012869:Skin Absorption
chemical_list: D005782:Gels; D008055:Lipids; D000078789:Polyacetylene Polymer; D011108:Polymers; D053279:Polyynes; C082361:polydiacetylene