Determination of bezafibrate and ciprofibrate in pharmaceutical formulations by densitometric and videodensito metric TLC

New simple TLC methods with densitometry and videoscanning have been developed for the quantitation of bezafibrate in Bezamidin tablets and ciprofibrate in Lipanor capsules. Analysis was performed on HPTLC Dint F-254 plates with hexane-tetrahydrofu ran, 8 + 2, as mobile phase. Detection was performed by densitometry at lambda = 227 nm and videoscanning at A = 254 nm. Calibration plots were constructed in the range 5-30 mu g per spot for both drugs. The calibration data were tested using several regression models and the optimum models were selected (quadratic for videoscanning and nonlinear y = ax(m) + b for densitometry; R-2 was always > 0.995). The active substances were extracted from tablets with methanol. The linearity of the method was tested by spotting different amounts of extracted solution (15-30 mg). The recovery function was always sufficiently linear, with an insignificant intercept and slope very close to unity. Accuracy was tested by quantitating three fortified samples (50, 100, and 150%); this resulted in homogeneous results without significant differences. Recovery measured by use of densitometry was 100.3% (RSD 7.84%) for bezalibrate and 98.01% (RSD 6.12%) for ciprofibrate. Videodensitometry resulted in recovery of 96.16% (RSD 9.8%) and 97.8% (RSD 11.2%), respectively. The F-Snedecor test and t-test for two means showed there was no significant difference between the precision and accuracy of the methods.