Author(s): Shakya AK, AlHiari YM, Alhamami OM
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Abstract A simple and sensitive method was developed for determination of irbesartan by liquid chromatography with fluorescence detection. Irbesartan and losartan (I.S.) in human plasma were extracted using diethyl ether:dichloromethane (7:3, v/v) followed by back extraction with 0.05 M sodium hydroxide. Neutralized samples were analyzed using 0.01 M potassium dihydrogen phosphate buffer (containing 0.07\% triethylamine as peak modifier, pH was adjusted with orthophosphoric acid to pH 3.0) and acetonitrile (66:34, v/v). Chromatographic separation was achieved on an ODS-C-18 column (100 mm x 4.6 mm i.d., particle size 5 microm) using isocratic elution (at flow rate 1.25 ml/min). The peak was detected using a fluorescence detector set at Ex 259 nm and Em 385 nm, and the total time for a chromatographic separation was approximately 13 min. The validated quantitation ranges of this method were 15-4000 ng/ml with coefficients of variation between 0.75 and 12.53\%. Mean recoveries were 73.3-77.1\% with coefficients of variation of 3.7-6.3\%. The between- and within-batch precision were 0.4-2.2\% and 0.9-6.2\%, respectively. The between- and within-batch relative errors (bias) were (-5.5) to 0.9\% and (-0.6) to 6.9\%, respectively. Stability of irbesartan in plasma was >89\%, with no evidence of degradation during sample processing and 60 days storage in a deep freezer at -70 degrees C. This validated method is sensitive and simple with between-batch precision of <3\% and can be used for pharmacokinetic studies.
This article was published in J Chromatogr B Analyt Technol Biomed Life Sci
and referenced in Pharmaceutica Analytica Acta