HPTLC method for guggulsterone. II. Stress degradation studies on guggulsterone

Stress degradation studies were carried out on guggulsterone (the hypolipidemic agent in the gum-resin exudates of Commiphora mukul) following the conditions prescribed in the parent drug stability testing guideline (Q1AR) issued by International Conference on Harmonization (ICH). The present study describes degradation of guggulsterone under different ICH prescribed stress conditions (acid and base hydrolysis, oxidation, dry and wet heat degradation and photodegradation) and establishment of a stability indicating HPTLC assay. The method employed TLC aluminium plates precoated with silica gel 60F-254 as the stationary phase. The solvent system consisted of toluene-acetone (9:1, v/v). Densitometric analysis of guggulsterone was carried out in the absorbance mode at 250 nm. This system was found to give compact spots for E- and Z-guggulsterone, (Rf value of 0.38 +/- 0.02 and 0.46 +/- 0.02, respectively) following double development of chromatoplates with the same mobile phase. The drug undergoes degradation under acidic and basic conditions, oxidation, dry and wet heat treatment and photodegradation. All the peaks of degraded products were resolved from the standard guggulsterone with significantly different Rf values. As the method could effectively separate the drug from its degradation products, it can be employed as a stability indicating one.