Determination of penciclovir in human plasma using LC with fluorescence detection: Application to a bioequivalence study

A novel HPLC method with fluorescence detection and one step sample preparation was developed for the determination of penciclovir in human plasma. Plasma samples (200 mu L) were deproteinized by precipitation with 100 mu L of perchloric acid and centrifuged. Separation was on an Inertsil ODS-3 column with a mixture of methanol-0.1% orthophosphoric acid as mobile phase. The fluorescence detector was set at Ex 270 nm, Em 375 nm. The assay was selective and linear with a limit of quantification of 0.025 mg L-1. The mean absolute recovery was 98.1%, while the intra- and inter-day coefficients of variation and percent error values of the assay method were all less than 100%. The assay was successfully applied in a randomized cross-over bioequivalence study of three pharmaceutical products containing 250 mg famciclovir (an oral prodrug of penciclovir) in 18 healthy volunteers.