HPTLC METHOD FOR ESTIMATION OF ISOTRETINOIN IN TOPICAL FORMULATIONS, EQUILIBRIUM SOLUBILITY SCREENING, AND IN VITRO PERMEATION STUDY

A new, simple, and rapid high-performance thin-layer chromatographic method was developed and validated for quantitative determination of Isotretinoin. Isotretinoin was chromatographed on silica gel 60 F-254 TLC plate using toluene - methanol (9.0+ 1.0 v/v) as the mobile phase. Isotretinoin was quantified by densitometric analysis at 340 nm. The method was found to give compact spots for the drug (R-F = 0.43 +/- 0.01). The linear regression analysis data for the calibration plots showed good linear relationship with r(2) = 0.9995 in the concentration range 100-500 ng/spot. The method was validated for precision, recovery, repeatability, and robustness as per the International Conference on Harmonization guidelines. The minimum detectable amount was found to be 13.72 ng/spot, whereas the limit of quantitation was found to be 41.58 ng/spot. Statistical analysis of the data showed that the method is precise, accurate, reproducible, and selective for the analysis of Isotretinoin. The method was successfully employed for the estimation of equilibrium solubility, quantification of Isotretinoin as a bulk drug, in commercially available preparation and in-house micro-emulsion based gel formulations.