Solid phase extraction of ayurvedic lipid based formulations for the analysis and the determination of active botanical ingredients by HPTLC

Abstract

Ayurvedic lipid based formulations falling under Sneha Kalpana in ayurvedic formulary were made by boiling the polyherbal decoction with oil or ghee with paste of other botanicals until the evaporation of water. The lipid nature and the contents of oil or ghee were tending to interfere with the determination of active botanical ingredients (ABIs) from Ayurvedic lipid based formulations in preparing the samples for the chromatographic analysis. Most of the earlier methods used for the sample preparation for the analysis of ayurvedic lipid based formulations were utilized either dissolving directly in a nonpolar solvent or liquid-liquid extraction with aqueous methanol (mostly 90% methanol) in determination of ABIs by HPLC, HPTLC and GC. Solid phase extraction on silica gel columns using hexane and 90% methanol was performed for the sample preparation. Both fractions were analyzed by HPTLC analysis on pre-coated silica gel 60 GF254 aluminium plates using Toluene: Ethyl acetate: Methanol (7:2:1) as mobile phase. The results have shown that the ABIs were maximally extracted in the methanol, the polar fraction whereas the non-polar fraction by hexane did not show the presence of ABIs. The visualization under UV light followed by densitometric analysis have shown an increased number of spots as well as highly concentrated spots with respect to the sample prepared from the formulation dissolved in hexane. The samples prepared by solid phase extraction produced the clear spots with good resolution in HPTLC when compared to the samples prepared by conventional methods and can be used for the determination and quantification of ABIs in these formulations.