title: Development and validation of a selective HPLC-UV method for thymol determination in skin permeation experiments.
abstract: Thymol is a natural monoterpene, whose antioxidant and antimicrobial properties suggest a potential use in topical formulations. A simple, precise and selective HPLC method for thymol determination in skin penetration studies was developed and validated in this paper. Separation was achieved with a RP-C18 column, mobile phase comprised of acetonitrile:water (35:65v/v), flow rate of 1.5mL/min, oven temperature at 40°C, injection volume of 30μL and UV detection at 278nm. The validation procedure certified the method was selective for thymol determination even when extracted from skin matrix extracts. It was also linear in a range from 0.5 to 15.0μg/mL, robust, precise and accurate, with recovery rates from the skin layers higher than 90%. Limits of detection and quantification were 0.05 and 0.14μg/mL, respectively. The method showed, therefore, to be adequate for use in further skin permeation studies employing thymol topical formulations.
authors.affiliation: Laboratory of Food, Drug and Cosmetics (LTMAC), School of Health Sciences, University of Brasilia, 70910-900 Brasília, DF, Brazil.
authors.forename: Tamara
authors.initials: T
authors.lastname: Angelo
authors.affiliation: Laboratory of Food, Drug and Cosmetics (LTMAC), School of Health Sciences, University of Brasilia, 70910-900 Brasília, DF, Brazil.
authors.forename: Felipe Q
authors.initials: FQ
authors.lastname: Pires
authors.affiliation: Laboratory of Food, Drug and Cosmetics (LTMAC), School of Health Sciences, University of Brasilia, 70910-900 Brasília, DF, Brazil.
authors.forename: Guilherme M
authors.initials: GM
authors.lastname: Gelfuso
authors.affiliation: Programa de Pós-Graduação em Biotecnologia, Federal University of Para, 66075-970 Belém, PA, Brazil.
authors.forename: Joyce K R
authors.initials: JKR
authors.lastname: da Silva
authors.affiliation: Laboratory of Food, Drug and Cosmetics (LTMAC), School of Health Sciences, University of Brasilia, 70910-900 Brasília, DF, Brazil.
authors.forename: Tais
authors.initials: T
authors.lastname: Gratieri
authors.affiliation: Laboratory of Food, Drug and Cosmetics (LTMAC), School of Health Sciences, University of Brasilia, 70910-900 Brasília, DF, Brazil. Electronic address: marciliofarm@hotmail.com.
authors.forename: Marcílio S S
authors.initials: MSS
authors.lastname: Cunha-Filho
mesh_terms: D000818:Animals; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D057230:Limit of Detection; D016014:Linear Models; D015203:Reproducibility of Results; D012867:Skin / Q000737:chemistry* / Q000378:metabolism*; D012869:Skin Absorption; D013552:Swine; D013943:Thymol / Q000032:analysis*
chemical_list: D013943:Thymol
keywords: HPLC method; Skin; Thymol; Topical formulation; Validation