High-performance thin layer chromatography method for estimation of conessine in herbal extract and pharmaceutical dosage formulations

A new, simple, sensitive, precise and robust high-performance thin layer chromatographic (HPTLC) method was developed for the estimation of conessime in herbal extracts and pharmaceutical dosage forms. Analysis of conessine was performed on TLC aluminium plates pre-coated with silica gel 60F-254 as stationary phase. Linear ascending development was carried out in twin trough glass chamber saturated with mobile phase consisting of toluene-ethylacetate-diethyl amine (6.5:2.5:1, v/v/v) at room temperature (25 +/- 2 degrees C). After derivatized the plate with modified Dragendroff's reagent, Camag TLC scanner III was used for spectrodensitometric scanning and analysis of the plate in absorbance mode at 520 nm. The system was found to give compact spots for conessine (R-f value of 0.82). The data for calibration plots showed good linear relationship with r(2) = 0.9998 in the concentration range of 1-10 mu g with respect to peak area. The present method was validated for precision and recovery. The limits of detection and quantification were determined. Statistical analysis of the data showed that the method is reproducible and selective for estimation of conessine. (C) 2007 Elsevier B.V. All rights reserved.