ANALYSIS OF PERILLIC ACID IN PLASMA BY REVERSED-PHASE HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY WITH ULTRAVIOLET DETECTION

A simple and sensitive isocratic high-performance liquid chromatograph ic (HPLC) method with UV detection for the quantitation of perillic ac id, a major circulating metabolite of perillyl alcohol and d-limonene, in plasma is described. Sample preparation involved protein precipita tion and subsequent transfer and dilution with 10 mM NaHCO3. The mobil e phase consisted of acetonitrile (36%) and 0.05 M ammonium acetate bu ffer pH 5.0 (64%). Separations were achieved on a C-18. column and the effluent monitored for UV absorption at the analytes' respective UVma x. Separation was excellent with no interference from endogenous plasm a constituents. This method was found suitable for quantifying drug co ncentrations in the range of 0.25 to 200.0 mu g/ml using a 0.05-ml pla sma sample, and was used to study the plasma pharmacokinetics of peril lic acid in mice.