[LC-MS/MS Determination of Tenofovir in Human Plasma and Its Bioequivalence].

Objective: To develop a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for detecting tenofovir in human plasma.

Methods: Twenty four healthy male volunteers received a single oral dose of 300 mg tenofovir disoproxil fumarate tablets under fasting and high-fat diet conditions in a randomized four-way crossover bioequivalence study with two preparations of tablets. Plasma samples were taken and analyzed using the LC-MS/MS method. The pharmacokinetic parameters of the two preparations were calculated and compared statistically to evaluate their bioequivalence using Phoenix Winnonlin6.3.

Results: Linear detection responses were obtained for tenofovir at the range from 3.13 to 500 ng/mL. The intra- and inter-day precisions were high,with lower than 5.43% [relative standard deviation ()%],high recovery and good stability. The 90% confidence intervals of peak concentration () of tenofovir and its area under the curve (AUC and AUC ) all fell within the bioequivalence limit 80.00%-125.00% under both fasting and high-fat diet conditions. No significant difference in peak time () was demonstrated between the two preparations (>0.05) .

Conclusion: The LC-MS/MS method can be used for simultaneous determination of tenofovir in human plasma. The two preparations of tablets are bioequivalent.