Rapid high performance liquid chromatographic method for determination of clarithromycin in human plasma using amperometric detection: application in pharmacokinetic and bioequivalence studies.

A rapid, sensitive and reproducible HPLC method using amperometric detector was developed and validated for the analysis of clarithromycin in human plasma. The separation was achieved on a monolithic silica column (MZ- C8 125×4.0 mm) using acetonitrile-methanol-potassium dihydrogen phosphate buffer (40:6:54,v/v), with pH of 7.5, as the mobile phase at a flow rate of 1.5 mL/min. The assay enables the measurement of clarithromycin for therapeutic drug monitoring with a minimum quantification limit of 20 ng/mL. The method involves simple, protein precipitation procedure and analytical recovery was complete. The calibration curve was linear over the concentration range of 0.1-6 µg/mL. The coefficients of variation for inter-day and intra-day assay were found to be less than 6%. This method was used in bioequivalency and pharmacokinetic studies of the test (generic) product 2 × 500 mg clarithromycin tablets, with respect to the reference product.

Sensitive and rapid HPLC method for determination of memantine in human plasma using OPA derivatization and fluorescence detection: application to pharmacokinetic studies.

A rapid, sensitive and reproducible HPLC method was developed and validated for the analysis of memantine in human plasma after derivatization with o-phthaldialdehyde (OPA) and fluorescence detection. Amantadine was used as internal standard. The derivatized memantine and amantadine were eluted in less than 10 min with no interference from endogenous plasma peaks. The analysis was carried out on a monolithic silica column (Chromolith Performance RP-18e, 100Ã4.6 mm). The mobile phase was composed of a mixture of acetonitrile and 0.025 M phosphate buffer (50:50, v/v, pH=4.6) with a flow rate of 2.5 mLmin(â1). The excitation and emission wavelengths were set at 335 nm and 440 nm respectively. The assay enables the measurement of memantine for therapeutic drug monitoring with a lower quantification limit of 2 ngmL(â1). The method involves simple extraction procedure and analytical recovery was 82.8Â 0.9%. The calibration curve was linear over the concentration range 2â80 ngmL(â1). The coefficients of variation for inter-day and intra-day assay were found to be less than 8%. The method was successfully applied to pharmacokinetic studies in humans.