A STABILITY INDICATING RP-LC METHOD FOR THE DETERMINATION OF STRYCHNINE IN KRIMIMUDGARA RASA

A reliable, rapid, simple and accurate high-performance liquid chromatography method with UV detection was developed for the simultaneous quantitative determination of strychnine in a polyherbal formulation prepared from Nux Vomica. Krimimudgara rasa, a herbal dosage form containing Strychnos nux vomica, Apium graveolens, Embellia ribes, Butea monosperma in combination. Separation of the strychnine from its major and minor degradation products was successfully achieved on a reversed-phase C-18 column using (250 mm × 4.6 mm ID, 5 µm particle size), with isocratic elution using a mixture of Methanol: KH₂PO₄ buffer solution (10 mmol, adjusted to pH 3 with orthophosphoric acid) (50:50 v/v) at flow rate 0.7 ml/min at 254 nm. The method was validated concerning linearity, precision, accuracy, system suitability and robustness. The responses were linear in the drug concentration range of 1 – 10 μg/ml. The percent recoveries were in the range between 98 – 101% from a mixture of degradation products. The utility of the procedure was verified by its application to a marketed formulation that was subjected to accelerated degradation studies. The method could distinctly separate the drug and degradation products. The products formed in marketed tablet dosage form were similar to those formed during stress studies.