Stability-indicating HPTLC method for quantitative estimation of silybin in bulk drug and pharmaceutical dosage form.

In the present study a novel stability-indicating high-performance thin-layer chromatography (HPTLC) method for quantitative determination of silybin in bulk drug and nanoemulsion formulation has been developed and validated on silica using solvent chloroform-acetone-formic acid (9 : 2 : 1 v/v/v) (R(f )of silybin 0.46 +/- 0.05) in the absorbance mode at 296 nm. The method showed a good linear relationship (r(2) +/- 0.999) in the concentration range 25-1500 ng per spot. It was found to be linear, accurate, precise, specific, robust and stability-indicating and can be applied for quality control and standardization of several multi-component hepatoprotective formulations as well as for stability testing of different dosage forms. The method proposed was also used to investigate the kinetics of acidic and alkaline degradation processes by quantification of drug at different temperature to calculate the activation energy and half-life for silymarin degradation. Copyright (c) 2009 John Wiley & Sons, Ltd.