Simple and Sensitive Spectrophotmetric Determination of Lamotrigine in Pure Form and in Dosage Forms

Abstract

Two new simple, sensitive and cost-effective spectrophotometric methods for the determination of lamotrigine (LMT) in bulk drug and in tablets are described. The methods are based on the measurement of absorbance of LMT either in 0.1 M H 2 SO 4 (method A) or in methanol (method B) at 225 nm. Linearity was found to be in the ranges, 0.5-5.0 and 1.25-12.5 µgmL-1 LMT, for method A and method B, respectively with apparent molar absorptivity values of 8.65×10 4 and 2.11×10 4 l mol-1 cm-1. The Sandell sensitivity values, limits of detection (LOD) and quantification (LOQ) values have also been reported for both the methods. The accuracy and precision of the methods were evaluated on intra-day and inter-day basis; the relative error (%RE) and the relative standard deviation (RSD) were <2.0%. The proposed methods were applied to the determination of the examined drug in coated tablet and no interference from any common pharmaceutical additives and diluents was observed. Results of assay were validated statistically by parallel analysis and by recovery studies.