Rapid high-performance liquid chromatographic analysis of procainamide and n-acetylprocainamide in plasma

ABSTRACT

A simple, rapid and reproducible high performance liquid chromatographic [HPLC] method for the determination of procainamide [P A] and its main metabolite N- acetylprocainamide [NAPA] in plasma has been developed and validated. The assay is performed after single extraction of PA, NAPA and atenolol [internal standard] from alkalinized plasma into chloroform. The drugs and the internal standard were eluted from adsorbsphere phenyl column with a mobile phase consisting of methanolwater [2773%, v/v] containing 0.03% triethylamine and adjusted with acetic acid to an apparent pH 4.5 at a flow rate of 1 ml/min. The effluent was monitored with a fluorescence detector set at 281 nm excitation wavelength and 356 nm emission wavelength. Standard curves for the analytes in plasma were linear [r > 0.999] in the range of 0.25-10 [micro]g/ml for PA and 0.1-10 micro g/ml for NAPA. The intraday coefficient of variation [CV] ranged from 2.58% to 6.32% for PA and from 0.95% to 2.60% for NAPA at three different concentrations. The interday CVs varied from 1.02% to 5.79% for P A and from 0.84% to 2.60% for NAPA. The relative recoveries of P A ranged from 90% to 104% and for NAPA from 95.3% to 108.0%. The method is applied for the determination of the pharmacokinetic parameters of P A and NAPA after oral administration of P A Durules [500 mg] tablet to five beagle dogs