Rapid Determination of Telmisartan in Human Plasma and Study of Bioequivalence of Its Tablets in Healthy Subjects

Objective: To develop a HPLC-ESI-MS assay for rapidly determinating telmisartan in human plasma and to evaluate the pharmacokinetics and bioequivalence of two telmisartan tablets in human. Methods: After being deproteined by acetonitril, plasma samples were separated by HPLC-ESI-MS on a reversed-phase C 18 column with a mobile phase of 10 mmol/L ammonium acetate buffer solution (pH 3.5)-methanol (9∶91,V/V) and a fragmentor voltage of 120 V, in which the target ions (m/z) were at 515.5 for telmisartan and 423.4 for the internal standard. The randomized crossover trial was performed in 20 healthy volunteers using the test tablets and reference tablets individually at a single 40 mg dose. Then blood samplings from the subjects were conducted for HPLC-ESI-MS analysis and the main pharmacokinetic parameters were determined thereby. Results: Calibration curve obtained was linear over the range of 0.3012～602.4 μg/L. Determination of a blood sample by this method was completed within 3.5 min. t 1/2, T max and C max were (24.7±4.2) h, (1.8±0.5) h and (219.2±119.0) μg/L for the reference tablets and (23.3±5.6) h, (1.7±0.7) h and (209.8±125.9) μg/L for the test tablets, individually. The relative bioavalability of the test tablets was (100.5±8.3)%. The results of variance analysis and two one-sided t-test showed that there was no significant difference between the two preparations in the AUC and C max. Conclusion: The assay was proved to be rapid, sensitive, accurate and convenient. The two preparations were bioequivalent.