An LC method has been developed and subsequently validated for the determination of Quetiapine fumarate and its related substances in bulk and pharmaceutical formulation. Separation was achieved in gradient mode using Kromasil 100, C18, 30 x 3.0 mm, 3.5 μm column with mobile phase A containing 0.5% Triethylamine buffer (pH adjusted to 4.8±0.05 with Orthophosphoric acid and mobile phase B containing 100%Acetonitrile at different time intervals as eluent at a flow rate 1.0mL/min. UV detection was performed at 240nm.The method is simple, selective and stability indicating .The described method is accurate and linear over a range of about 0.052μg/mL to 3.289μg/mL.The method precision for the determination of related impurities was below 3.5% RSD .The Percentage recoveries of known related impurities from dosage forms ranged from 96.7 to 106.920%. LOD and LOQ of all related impurities of Quetiapine fumarate was established and ranged from 0.017μg/ml - 0.027μg/ml for LOD and 0.052μg/ml – 0.086μg/ml for LOQ .The method is useful in the quality control of bulk manufacturing and also in pharmaceutical formulations. ______________________________________________________________________________
