Rapid determination of valaciclovir and acyclovir in human biological fluids by high-performance liquid chromatography using isocratic elution

A rapid high-performance liquid chromatographic assay with isocratic elutio n is developed for the simultaneous quantification of valaciclovir (VACV) p rodrug and its active converted compound, acyclovir (ACV), in biological fl uids of treated patients. For serum, the samples are deproteinized with per chloric acid in presence of 1-methylguanosine as the internal standard (IS) . For urine and dialysis liquid, the samples are diluted with a mobile phas e containing the IS, then filtered. VACV, ACV and the IS are separated on a SymmetryShield(TM) RP-8 column with acetonitrile-ammonium phosphate buffer as the mobile phase and detected at 254 nm. The chromatographic time is ab out 12 min. The relative standard deviations (RSD) of VACV and ACV standard s are between 0.5 and 3.5%. Most endogenous nucleosides and their metabolit es, psychotropic drugs and drugs of abuse are shown not to interfere with t his technique. The method has been applied to study the pharmacokinetics of VACV and ACV in serum, dialysis liquid and urine of renal failure patients on continuous ambulatory peritoneal dialysis (CAPD) under oral treatment o f VACV. (C) 1999 Elsevier Science B.V. All rights reserved.