DETERMINATION OF LAMOTRIGINE IN TABLETS USING HPTLC, HPLC, AND DERIVATIVE SPECTROPHOTOMETRY METHODS

Abstract

The determination of lamotrigine in tablets using high-performance thin-layer chromatography (HPTLC), high-performance liquid chromatography (HPLC), as well as direct, first, second, and third derivative ultraviolet spectrophotometry methods are described. HPTLC method was performed using silica plates, a mobile phase composed of toluene:acetone:ammonia (3:7:0.5, v/v/v), and a densitometric detection at 312 nm. Moreover, quantification was achieved in the concentration range of 0.25–10.0 µg/spot and with good precision (RSD = 2.19%) and recovery (97.92%), using a nonlinear calibration curve by fitting to y = a + blnx. HPLC method was performed using a Luna C18 column and isocratic elution mode with a mobile phase composed of methanol: phosphate buffer (25:75, v/v) and delivered at a flow rate 1.2 mL/min. Proposed HPLC method provided good results of precision (RSD = 1.86%) and recovery (101.51%) in the concentration range of 0.25–7.5 µg/mL using linear y = a + bx regression analysis. For the UV-derivative spectrophotometry method, all derivatives and wavelengths studied proved accurate linearity, precision (RSD = 0.96–1.87%), and recovery (96.74–101.90%). Moreover, no interference was found from tablet excipients at the selected wavelength and assay procedures. The developed methods were found to be validated and showed good precision and reproducibility.

Keywords:

• antiepileptic drugs
• derivative spectrophotometry
• high-performance liquid chromatography (HPLC)
• high-performance thin-layer chromatography (HPTLC)
• lamotrigine
• pharmaceutical formulations

Notes

^a Correlation coefficient.

^b The percentage of recoveries of the data obtained for studied compound calculated for 6 independent measurements, respectively.

^c Percentage of relative standard deviations calculated for 6 independent measurements, respectively.

^{d , e} Declarated and found mean content of studied compounds in one tablet, respectively.

^a D (direct), D₁ (first derivative), D₂ (second derivative), D₃ (third derivative) spectra, respectively.

^b Correlation coefficient.

^c Coefficient of a (intercept), b (slope), respectively, tested at 95% confidence level using point hypothesis tests. “+,” essential, ”–,” not essential.

^d , ^e Declarated and found mean content of studied compounds in one tablet, respectively.

^f The percentage of recoveries of the data obtained for studied compound calculated for 6 independent measurements.

^g Percentage of relative standard deviations calculated for 6 independent measurements.