Abstract: AIM: To investigate the pharmacokinetic profile and relative bioavailability of Famciclovir sustained release capsules in healthy volunteers.METHODS: 12 healthy volunteers were divided into four group with single oral dose test famciclovir sustained release capsules(250, 375, 750mg) and conventional Facmciclovir tablets (750 mg) according to an open randomized four way crossover design.A multidose test were given to 10 healthy volunteers according to an open randomized two way crossover design.The concentration of penciclovir in plasma after administration were determinded by HPLC.Pharmacokinetic parameters were calculated with 3P97 program.RESULTS: Concentration-time curves of penciclovir fitted to one-compartment mode, C_max were (0.31±0.06), (0.51±0.09), (1.0±0.16) μg/mL, t_max (4.4± 1.8), (4.0±1.4), (4.3±1.8) h, MRT (6.9± 1.3), (7.3±1.0), (7.6±0.7) h, AUC_0-24 (3.3± 0.8), (5.2±1.1), (11.3±1.4) μg·mL^-1·h respectively for famciclovir sustained release capsules;C_max were (3.81±0.38) μg/mL, t_max (1.2±0.6) h, MRT (3.3±0.4) h, AUC_0-24 (13.7±1.5) μg·mL^-1·h for conventional tablet.The relative bioavailability was 81.96%±2.54%.The parameters after multi-doses of the sustain released capsules and conventional tablets were as follows: C_min (0.32±0.13) and (0.16± 0.04) μg/mL, C_max (0.71±0.14) and 1.67±0.44 μg/mL, C_av (0.44± 0.09) and (0.56± 0.13) μg/mL, DF 90%±26% and 270%±59%, respectively.CONCLUSION: The sustain released capsules have the obvious sustained release characteristic.The two formulation of Famciclovir are of bioequivalence.

Key words: Famciclovir sustained released capsules, pharmacokinetics, relative bioavailability, HPLC