Determination of free and conjugated cis-3,3,5-trimethylcyclohexanol in plasma and urine

A gas chromatographic procedure was developed to determine free and conjugated cis-3,3,5-trimethylcylcohexanol in plasma and urine. The sample is extracted with dichloromethane when free cis-3,3,5-trimethylcyclohexanol is determined, or with hexane after enzymatic hydrolysis, when conjugated cis-3,3,5-trimethylcyclohexanol is determined. An aliquot of the organic extract is injected into a stainless-steel column (packed with Carbowax 20M, 15% on Chromosorb W AW 100-120 mesh) and detected with a flame ionization detector. Extraction recovery from plasma and urine was almost 100% and the limit of quantification was fixed at 100 ng/ml plasma or urine. The procedure was evaluated in a pharmacokinetic study of cyclandelate and its metabolite cis-3,3,5-trimethylcyclohexanol.