Stability indicating assay of secnidazole in the presence of its degradation products.

Four new selective, precise, accurate and rapid first derivative spectrophotometric, RP-HPLC, TLC densitometric and colorimetric methods are described for the determination of secnidazole in the presence of its degradation products, 2 - methyl - 5 - nitroimidazole and hydroxy propanol.( Method A)is applying the first derivative spectrophotometry at 296 nm. (Method B) is RP- HPLC based on using 30% methanal as a mobile phase at a flow rate of 1.0 ml/min. and 5 mu Bondapak C-18 column (5 micron, 150 X 4.6 mm) as a stationary phase. Detection was carried out using a diode detector at 319 nm. ( Method C) is densitometry using ethyl acetate as mobile phase and the spot was scanned with a spectrodensitometry at 311 nm. ( Method D) is colorimetry based on diazotization of sulfanilamide with the nitrite ions liberated by alkaline hydrolysis of secnidazole and subsequent coupling of the diazonium salt with N-1-(naphthyl)-ethylenediamine dihydrochloride. Regression analysis of a Beer's plot showed good correlation in the concentration 4 - 30 mu g ml(-1), 2-20 mu g.ml(-1), 4-18 mu g, 0.8-6.0 mu g.ml(-1) with mean percentage recoveries:99.87 +/- 0.56%, 100.12 +/- 0.80%, 99.33 +/- 0.50% and 99.68 +/- 0.39% for methods A, B, C and D, respectively. These methods are suitable for stability testing of secnidazole in bulk powder retaining their accuracy in the presence of up to 70% for method A and up to 90% for method B, C and D. The proposed methods were applied for the analysis of pharmaceutical formulations and the recoveries were 99.40 - 100.52%. The results obtained compared statistically with those obtained with the reported method.