Comparative validation of HPLC, densitometric and videodensitometric determination of lamotrigine in pharmaceutical

Simple, sensitive, precise and accurate HPLC, densitometric and videodensitometric methods for determination of lamotrigine in tablet forms were developed and validated. The HPLC method was carried out using a Symmetry C8 column and a mobile phase acetonitrile-phosphate buffer pH 2.80 (25:75, v/v), with a flow rate of 1 mL/min, and UV detection at 210 nm. Ethosuximide was used as the internal standard. Densitometric and videodensitometric analysis was performed on silica gel 60 F254 plates, in horizontal chambers, with methanol-chloroform-ammonia (25%) 1.5:7.5:1, (v/v) as mobile phase. Densitometric detection was performed at 225 nm and at 315 nm, and videodeoscanning at 254 nm. Calibration plots were constructed in the range 0.5-10 μg/spot, with good correlation coefficients r > 0.99 for both methods. The precision and accuracy of all elaborated methods were compared. Finally, the developed methods were applied for the quality control of lamotrigine tablets.