Pharmacokinetics and relative bioavailability study of multiple oral doses of pyridostigmine bromide sustained-release tablets in rabbits

Objective To evaluate the pharmacokinetics and the relative bioavailability of pyridostigmine bromide sustained-release tablets(PBSTs) by comparing with the conventional tablets using a multiple-dose design. Methods Six rabbits were randomly divided into 2 groups and were assigned to a self crossover design.The plasma pyridostigmine bromide concentration was determined by high-performance liquid chromatography as multiple oral dose of PBSTs(90 mg each time,and twice a day) or conventional tablets(60 mg each time,three times a day).The pharmacokinetic parameters and relative bioavailability were calculated.Results A two-compartment model was used to describe the in vivo behavior of PBSTs after oral administration.The main pharmacokinetic parameters for conventional tablets and multiple oral dose of PBSTs were calculated as the follows: tmax(2.00±0) and(4.00±0) h;Cmax(25.48±0.18) mg/L and(19.24±0.45) mg/L;AUC0-∞(321.42±5.00) mg·h·L-1 and(370.08±12.23) mg·h·L-1.The relative bioavailability of the sustained-release tablets was 119.15% compared with the conventional tablets. Conclusion PBSTs has the property of sustained-relsease and is bioequivalent to the conventional tablets.