Sensitive and Cost-Effective TLC-Densitometric Method for Determination of Metronidazole and Tinidazole in Tablets

A sensitive, easy-to-use, fast, and cost-effective TLC-densitometric method was developed for the separation of metronidazole, secnidazole, ornidazole, tinidazole, and 2-methyl-5-nitroimidazole and for the determination of metronidazole and tinidazole in Metronidazole Polpharma and Tinidazolum Polpharma tablets. Analyses were performed on chromatographic plates precoated with silica gel 60F254 using chloroform + methanol + diethylamine in a volume ratio of 9:1:1 as the optimal mobile phase. The method has been validated. The intraday and interday precision values for the three different concentrations ranged from 0.99% to 1.48% and 0.89% to 1.76%, and the precision values ranged from 1.13% to 2.48% and 0.95% to 2.49% for metronidazole and tinidazole, respectively. The limit of quantification (LOQ) was 0.036 and 0.066 mu g/spot for metronidazole and tinidazole, respectively. The mean recovery was 103.1% and 100.6% for metronidazole and tinidazole, respectively. The content of metronidazole and tinidazole in tablets in relation to the content declared by the manufacturer was 101.3% and 99.8%, respectively. The obtained results were verified using the pharmacopeial method. The presented method is fast, sensitive, precise, selective, accurate, and robust. It allows for the analysis of several samples on one chromatography plate at the same time.