High-performance liquid chromatography method for the quantification of non-radiolabelled cinnamic compounds in analytes derived from human skin absorption and metabolism experiments

An isocratic high-performance liquid chromatography method has been develop ed for the quantification of the skin sensitisers trans-cinnamaldehyde and trans-cinnamic alcohol, and their cinnamic metabolites. The relative standa rd deviations (RSDs) between the gradients of eight sets of standard curves were 2.8, 3.1 and 1.9% for cinnamic alcohol, cinnamaldehyde and cinnamic a cid, respectively. Sample analytes were derived from two series of experime nts: in vitro full-thickness human skin absorption and metabolism studies a nd metabolism studies using human skin homogenates, with non-radiolabelled cinnamic compounds. Skin absorption and metabolism experiments were perform ed in the absence and presence of the alcohol dehydrogenase inhibitor, pyra zole. Samples from full-thickness skin absorption studies were analysed wit hout extraction: cinnamic compounds from within skin were extracted into me thanolic solutions using newly developed methods. The intra-assay RSDs rang ed from 0.17 to 2.52% for cinnamic alcohol, 0.24 to 9.14% for cinnamaldehyd e and 0.26 to 6.43% for cinnamic acid. The inter-assay RSDs for cinnamic al cohol, cinnamaldehyde and cinnamic acid, respectively, as determined from n = 20 HPLC runs. were 2.10, 4.16 and 2.16%. (C) 2001 Elsevier Science B.V. All rights reserved.