Determination of minocycline in human plasma by high-performance liquid chromatography coupled to tandem mass spectrometry: application to bioequivalence study.

Minocycline was determined in human plasma by HPLC-MS-MS using clarithromycin as an internal standard. The method is fast (single liquid extraction and run time of <3 min) and sensitive (5 ng/ml) and it was employed in a bioequivalence study of two 100 mg tablet formulations in 24 healthy volunteers. The 90% confidence interval of the individual ratio geometric mean for both AUC(0-96 h) and Cmax were 99.2-111.1% and 95.6-117.5%, respectively. Thus, Minoderm was considered bioequivalent to Minomax according to both the rate and extent of absorption. No food interaction was observed with either formulation.