ABSTRACT
OBJECTIVE: The aim of the study was to develop a simple, sensitive and cost-efficient bioanalytical method for the simultaneous determination of niclosamide and bicalutamide in rat plasma with appropriate validation. MATERIAL AND METHODS: Real-time estimation was carried out using Ultra Flow Liquid Chromatography. The solvent system consisting of 20mM sodium acetate buffer at pH 4.0 and acetonitrile (65: 35% v/v) is used as the mobile phase. The analytes were extracted by protein precipitation with acetonitrile and separated on an Eclipse plus C18 Column (25cm×5cm×4.6µm) with L1 packing in isocratic mode with a flow rate of 1ml/min at 254nm. The developed method was validated on the basis of the bioanalytical guidelines of the US American FDA. RESULT: The retention times of niclosamide and bicalutamide were 4.19min and 8.61min, respectively, with a running time of 15minutes. The calibration ranges are 50-600ng/ml for niclosamide and 100-1200ng/ml for bicalutamide. Regression equations for niclosamide and bicalutamide were y=55746x - 1E+06 and y=22051x-576888 with regression coefficient (R2) 0.9952 & 0.9982 using the unweighted and weighted linear regression with a weighting factor of 1/xo, 1/x, 1/âx, and 1/x2. The accuracy of niclosamide and bicalutamide were 46.01ng/ml to 584.10ng/ml and 82.30ng/ml to 1149.13ng/ml, respectively. The percentage recoveries for niclosamide and bicalutamide were 86.51-90.29% & 88.64-93.99%, respectively. CONCLUSIONS: The result of the present study show that the method developed is a simple, fast and precise method and is used in bioavailability and bioequivalence studies as well as during routine therapeutic drug monitoring of niclosamide and bicalutamide.
