Jeffery J Prusakiewicz1, Chrisita Ackermann, Richard Voorman. 1. Department of Pharmacokinetics, Dynamics and Metabolism, Pfizer Global Research and Development, 2800 Plymouth Rd., Ann Arbor, Michigan 48105, USA. Jeff.Prusakiewicz@pfizer.com
Abstract
PURPOSE: Many topically applied drugs contain esters that are hydrolyzed in the skin. Minipigs have emerged as potential models of human dermatology and, in some aspects, may be superior to commonly used rat skin. The aims of this study were to evaluate the suitability of minipig and rat skin as in vitro models of human epidermal esterase activity. METHODS: Naphthyl acetate and para-nitrophenyl acetate were tested as prototypical substrates of carboxylesterases from skin, plasma, and liver. Reaction products were monitored by high-performance liquid chromatography/ultraviolet analysis. RESULTS: Hydrolysis efficiency in skin was higher than plasma, but lower than liver. The esterase efficiency of rat skin microsomes (580-1100 min(-1) mg(-1)) was two to three orders of magnitude higher than human (1.3-4.2 min(-1) mg(-1)) and minipig microsomes (1.2-4.2 min(-1) mg(-1)). Rat skin cytosol (80-100 min(-1) mg(-1)) was 2- to 10-fold more efficient than human (2.4-67 min(-1) mg(-1)) or minipig cytosol (18-61 min(-1) mg(-1)). Most importantly, human skin fractions displayed kinetics of hydrolysis very similar to minipig skin. CONCLUSIONS: These studies show minipig skin as an appropriate, potentially valuable model for human epidermal ester metabolism and support the use of minipig skin in preclinical development of topically applied compounds.
PURPOSE: Many topically applied drugs contain esters that are hydrolyzed in the skin. Minipigs have emerged as potential models of human dermatology and, in some aspects, may be superior to commonly used rat skin. The aims of this study were to evaluate the suitability of minipig and rat skin as in vitro models of human epidermal esterase activity. METHODS:Naphthyl acetate and para-nitrophenyl acetate were tested as prototypical substrates of carboxylesterases from skin, plasma, and liver. Reaction products were monitored by high-performance liquid chromatography/ultraviolet analysis. RESULTS:Hydrolysis efficiency in skin was higher than plasma, but lower than liver. The esterase efficiency of rat skin microsomes (580-1100 min(-1) mg(-1)) was two to three orders of magnitude higher than human (1.3-4.2 min(-1) mg(-1)) and minipig microsomes (1.2-4.2 min(-1) mg(-1)). Rat skin cytosol (80-100 min(-1) mg(-1)) was 2- to 10-fold more efficient than human (2.4-67 min(-1) mg(-1)) or minipig cytosol (18-61 min(-1) mg(-1)). Most importantly, human skin fractions displayed kinetics of hydrolysis very similar to minipig skin. CONCLUSIONS: These studies show minipig skin as an appropriate, potentially valuable model for human epidermal ester metabolism and support the use of minipig skin in preclinical development of topically applied compounds.
Authors: Jakub Novotný; Petra Kovaríková; Michal Novotný; Barbora Janůsová; Alexandr Hrabálek; Katerina Vávrová Journal: Pharm Res Date: 2008-11-14 Impact factor: 4.200
Authors: Antonia M Calafat; Xiaoyun Ye; Lee-Yang Wong; Amber M Bishop; Larry L Needham Journal: Environ Health Perspect Date: 2010-01-04 Impact factor: 9.031