A high performance liquid chromatography method for simultaneous determination of rosiglitazone and gemfibrozil in human plasma.

A high performance liquid chromatography (HPLC) method was developed for the simultaneous determination of rosiglitazone and gemfibrozil in human plasma using alpha-asarone as an internal standard (IS). Plasma samples were pretreated by protein precipitation. The analytes were separated on a Macherey-Nagel Nucleodur C(18) (250 mm x 4.6 mm, 5 microm) column using acetonitrile and 30 mmol/l ammonium acetate solution (including 0.1% methanoic acid) as mobile phase which was delivered at 1.2 ml/min. A gradient elution program was adopted to adjust proportion of solvent in mobile phase. A time program was used to regulate conditions of fluorescence detection. The method was validated over the concentration range of 5.0-751.3 ng/ml for rosiglitazone and 0.5-75.4 microg/ml for gemfibrozil with acceptable accuracy, precision and extraction recoveries. This method is suitable for routine therapeutic drug monitoring and pharmacokinetic interaction study of the two drugs.