Rapid and sensitive determination of selective progesterone modulator ulipristal acetate in human plasma

Ulipristal acetate is a new synthetic selective progesterone receptor modulator developed mainly as emergency contraceptive (EC) and also used for the treatment of uterine fibroids. A cost effective, sensitive, simple and rapid high performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the analysis of ulipristal acetate in human plasma. Following liquid-liquid extraction, the analyte (Ulipristal acetate) and internal standard (Levonorgestrel) were chromatographed using mobile phase in an isocratic elution mode on a reverse phase C18 column. The LC-MS/MS operated in multiple reaction monitoring mode for respective [M+H]+ ions, m/z 476.2/134.1 for analyte and 313.3/245.1 for internal standard. The assay exhibited linear dynamic range of 1-300 ng/mL. The lower limit of quantification was 1 ng/mL with relative standard deviation of 7.0%. The intra-batch and inter-batch results were precise with coefficient variation of 2.7 to 7.0 (%) and accuracy of 94.2-99.8 (%). The validated method was simple, fast and repeatable for bioequivalence, pharmacokinetic and therapeutic monitoring studies

LC-MS/MS Quantification of Tramadol and Gabapentin Utilizing Solid Phase Extraction

An accurate, highly sensitive, and precise method for quantitative analysis of tramadol (TMD) and gabapentin (GBP) by high performance liquid chromatography and tandem mass spectrometry in human plasma was proposed and validated successfully using venlafaxine and pregabalin as internal standards (ISTDs), respectively. An aliquot of 200 μL of plasma was mixed with internal standard dilution and extraction was performed by using solid phase extraction (SPE) technique. Peak resolution was achieved on Phenomenex PFP column (50×4.6 mm, 2.6 μm). The total analytical run time was 3.8 min. Both analytes were monitored using multiple reaction monitoring (MRM) scan and the mass spectrometer was operated in positive polarity mode. The method was validated for specificity, sensitivity, precision, accuracy, and other analytical parameters. The results found were satisfactory over the linear calibration range of 1-500 ng/mL and 10-6000 ng/mL for TMD and GBP, respectively. The developed method can be ready to use by scientific community for quantification of analytes in plasma samples from various clinical studies of different dose strengths