High-performance thin-layer chromatographic determination of etoricoxib in the bulk drug and in pharmaceutical dosage form

A sensitive, accurate, precise, and stability-indicating high-performance thin-layer chromatographic method has been established and validated for analysis of etoricoxib in both bulk drug and formulations. Chromatography is performed on aluminum-backed silica gel 60F₂₅₄ plates with toluene-1,4-dioxane-methanol 8.5:1.0:0.5 (v/v) as mobile phase. This system furnished compact bands for etoricoxib (R_F 0.24). Rofecoxib (R _F 0.38) was used as internal standard. Densitometric analysis of etoricoxib was performed in absorbance mode at 235 nm. Linear regression data for the calibration plots showed there was a good linear relationship between response and amount of etoricoxib in the range 100-1500 ng per spot; the correlation coefficient was 0.9922 ± 0.001. The mean values of the slope and intercept of the plot were 280.14 ± 0.26 and 320.01 ± 0.22, respectively. The method was validated for precision, accuracy, robustness, and recovery. The limits of detection and quantitation were 30 and 100 ng per spot, respectively. The drug undergoes degradation when subjected to neutral, acidic, or basic hydrolysis, oxidation, or dry heat treatment, but the degradation products were well separated from the drug (different R _F values). Because the method could effectively separate the drug from its degradation products it can be regarded as stability-indicating.