Abstract: AIM: To study the bioavailability of granisetron nasal spray in beagles.METHODS: A single 2 mg dose of granisetron tablet or nasal spray was given to beagles in a randomized crossover design.The drug plasma concentrations were determined by HPLC fluorescence method using bisoprolol fumarate as internal standard.RESULTS: The pharmacokinetic parameters of granisetron tablet and nasal spray were as follow:tmax were 1.50±0.41 and 0.31±0.13 h,C_max were 6.45±1.15 and 11.93±1.33ng·ml^-1,AUC_0-12 were 25.14±3.75 and 27.76±3.46ng·h·ml^-1,AUC_0-∞ were 28.46±4.17and 31.46±3.43ng·h·ml^-1,respectively.The mean relative bioavailability of nasal spray vs tablet was(111.88±18.94)%.CONCLUSION: Granisetron nasal spray is readily absorbed and owns better bioavailability than the tablet.

Key words: granisetron, HPLC, pharmacokinetics, bioavailability