Determination of Lormetazepam in Tablets Using High-Performance Thin-Layer Chromatography, High-Performance Liquid Chromatography, and Derivative Spectrophotometry Methods

This study describes the development and validation of some analytical methods as high-performance thin-layer chromatography (HPTLC), ultraviolet (UV)–densitometry, UV–high-performance liquid chromatography (HPLC), and derivative spectrophotometry elaborated for the estimation of lormetazepam in pharmaceutical formulations. HPTLC method was performed using silica plates, a mobile phase composed of acetonitrile–water (6:4, v/v), and a densitometric detection at 241 nm. UV–derivative spectrophotometry method was applied, and at first, the direct spectrum was recorded, then first-, second-, and third-derivative spectra were obtained and measured by peak-zero (P-0) or peak-peak (P-P) techniques. Moreover, HPLC method was performed using a Gemini C18 column and isocratic elution mode with a mobile phase composed of acetonitrile–water (65:35, v/v) and delivered at a flow rate of 0.5 mL min−1. In the case of HPTLC analysis, the quantification was achieved with acceptable precision (relative standard deviation [RSD] = 5.39%) and recovery of 98.53%, using a nonlinear calibration curve. For the UV–derivative spectrophotometry method, all derivatives and wavelengths studied proved good linearity, precision (RSD = 2.30–6.13), and recovery (91.17–98.70%). On the other hand, the elaborated HPLC method provided good results of precision (RSD = 2.16%) and recovery of 97.60% in the concentration range of 1.95–62.5 μg mL−1 using linear regression analysis. It was concluded that the best results were found for HPLC method; however, all the developed methods can be considered comparable and successfully applied to the routine quality control of this drug in dosage form.