title: Evaluation of the skin blanching of topically applied steroids using a chroma meter in animals.
abstract: We evaluated the utility of animal skins for determining the skin blanching of steroids. A Chroma Meter was used to determine the skin blanching of steroids. Hydrophilic creams containing clobetasol propionate (CP) or prednisolone (PS) were selected as model steroid formulations. Skin blanching, a*, was determined using a Chroma Meter after the application of 0.005, 0.01, 0.1, or 1.0% CP or PS hydrophilic cream to the back skin of guinea pigs and hairless rats for 24 h. The relationships between Δa*(6h) and the skin concentrations of the steroids were determined at 6 h after removal of the cream. Δa*(6h) was markedly decreased after the application of CP hydrophilic cream to guinea pigs, and a good linear relationship was observed between Δa*(6h) and skin concentration (r=0.98). In contrast, no relationship was observed between these parameters after the application of CP cream to the hairless rats. Although skin blanching was observed after PS cream application in guinea pigs, no relationship was observed between Δa*(6h) and skin concentration of PS in each animal. These results suggest that the skin blanching effect of CP in guinea pigs is greater than that of PS and that its blanching effect in guinea pigs was stronger than that in hairless rats. Guinea pigs were found to be a good animal model for determining the skin blanching produced by steroid creams. In addition, Chroma Meters can be effectively used in skin vasoconstrictive tests in guinea pigs.
authors.affiliation: Pharmaceutical Sciences, Josai University, Saitama 350-0295, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ishii
authors.forename: Konomi
authors.initials: K
authors.lastname: Fujino
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Todo
authors.forename: Kenji
authors.initials: K
authors.lastname: Sugibayashi
mesh_terms: D000287:Administration, Topical; D000818:Animals; D001808:Blood Vessels / Q000187:drug effects / Q000503:physiopathology; D002990:Clobetasol / Q000493:pharmacokinetics / Q000494:pharmacology*; D003124:Colorimetry / Q000295:instrumentation / Q000379:methods*; D005938:Glucocorticoids / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000494:pharmacology*; D006168:Guinea Pigs; D008297:Male; D011239:Prednisolone / Q000493:pharmacokinetics / Q000494:pharmacology*; D051381:Rats; D054772:Rats, Hairless; D012867:Skin / Q000098:blood supply* / Q000737:chemistry / Q000378:metabolism; D014661:Vasoconstriction / Q000187:drug effects* / Q000502:physiology
chemical_list: D005938:Glucocorticoids; D011239:Prednisolone; D002990:Clobetasol