ABSTRACT:
A stability indicating High Performance Thin Layer Chromatographic [HPTLC] method was developed for the study of stability of the drug Ofloxacin. Bioautography was performed subsequently to compare the results by both the methods. The method employed TLC (Thin Layer Chromatography) aluminum plates pre-coated with silica gel 60 F254 as the stationary phase. The samples were spotted on TLC plates (10cmx20cm) as 4 mm bands and developed with a mobile phase consisting of n-butanol AR: ethanol AR: ammonia solution AR (5:5:4 v:v:v). The Rf value for Ofloxacin was 0.53 ± 0.03. The drug was exposed to various stress conditions as per ICH guideline viz. acidic, alkaline, neutral hydrolysis, oxidation and photolysis after which the amount remaining was estimated. Densitometric analysis of Ofloxacin was carried out at 299nm. The linear regression analysis data for the area of the bands resulted in correlation coefficient r2 = 0.9859 in the range of 500–2500 ng / band. The same TLC plates were used to perform Bioautography in petri plates (10cm diameter) using Mueller Hinton agar as the media and Escherichia coli NCIM 2066 as the organism. The results by both the methods were compared. The drug does not undergo degradation with neutral hydrolysis and oxidative conditions, but gets affected in alkaline hydrolytic and acidic hydrolytic conditions. As the HPTLC method could effectively resolve the drug from its degradation products, it can be employed as a stability-indicating method.