Objective: A simple, sensitive, and specific thin layer chromatography (TLC) densitometry method has been developed for the simultaneous quantification of strychnine and brucine in the seeds of Strychnos nux-vomica.
Materials and methods: The method involved simultaneous estimation of strychnine and brucine after resolving it by high performance TLC (HPTLC) on silica gel plate with chloroform-methanol-formic acid (8.5:1.5:0.4 v/v/v) as the mobile phase.
Results: The method was validated as per the ICH guidelines for precision (interday, intraday, intersystem), robustness, accuracy, limit of detection, and limit of quantitation. The relationship between the concentration of standard solutions and the peak response was linear within the concentration range of 50-1000 ng/spot for strychnine and 100-1000 ng/spot for brucine. The method precision was found to be 0.58-2.47 (% relative standard deviation [RSD]) and 0.36-2.22 (% RSD) for strychnine and brucine, respectively. Accuracy of the method was checked by recovery studies conducted at three different concentration levels and the average percentage recovery was found to be 100.75% for strychnine and 100.52% for brucine, respectively.
Conclusions: The HPTLC method for the simultaneous quantification of strychnine and brucine was found to be simple, precise, specific, sensitive, and accurate and can be used for routine analysis and quality control of raw material of S. nux-vomica and several unani and ayurvedic formulations containing this as an ingredient.
Keywords: HPTLC; brucine; method development; strychnine; validation.