Development and optimization of a reversed-phase high-performance liquid chromatographic method for the determination of piperacillin and tazobactam in tazocin injectable powder.

A reversed phase high-performance liquid chromatographic method with detection at 220 nm was developed and validated for the determination of piperacillin, I, and tazobactam, II, in Tazocin injectable powder. Acetaminophen was used as internal standard. A Hypersil BDS RP-C(18) column (250 x 4.6 mm), 5 microm particle size, was equilibrated with a mobile phase composed of aqueous solution of sodium dihydrogenphosphate-dihydrate (20 mM)-acetonitrile-methanol (70:15:15, v/v/v) and pH 5.0. Its flow rate was 1.0 ml/min. Calibration curves were linear for I and II in the concentration ranges of 3.0 x 10(-7)-2.0 x 10(-4) M and 7.0 x 10(-7)-2.0 x 10(-4) M, respectively. Limits of detection and quantitation were 1 x 10(-7), 3 x 10(-7) M for I and 2 x 10(-7), 7 x 10(-7) M for II, respectively. Relative standard deviation, for I and II was less than 0.40 and 0.75%, respectively. Extensive recovery studies were also performed.