STABILITY-INDICATING DENSITOMETRIC, FLUORIMETRIC AND DIFFERENCE ABSORBANCE (∆A) METHODS FOR THE DETERMINATION OF SOTALOL - HCl

Three simple, accurate and precise stability-indicating methods are presented for the quantitative estimation of sotalol-HCl in presence of its degradation products. The first is based on TLC separation of the drug from its degradates followed by densitometric measurement of the intact drug at 230 nm using a developing system composed of methanol- chloroform- conc. ammonia (7:3:0.05 by volume). The second method measures the fluorescence intensity of sotalol-HCl in ethanol at em 306 nm after its excitation at 238 nm, whilst the third one depends on measurement of pH absorbance difference (A) of the drug solution between 0.1M HCl and 0.1 M NaOH at 249 nm. Regression analysis of Beer’s plots shows good correlations (r = 0.9996 - 0.9997) over concentration ranges of 2 - 17.5 μg / spot, 1 - 15 μg mL -l and 2 – 20 μg mL -l of the drug for the three suggested methods, respectively. The three methods retain their accuracy in the presence of up to 80%, 70% or 60% degradant, respectively. The proposed methods are also successfully applied to analyze sotalol-HCl in its formulation; Betacor® tablets with mean recoveries ranging from 99.23 to 99.97 %. The results obtained are validated and statistically analysed and found to be in accordance with those given by a reported method.