ABSTRACT
Four simple, accurate, sensitive, selective and economic spectroscopic methods were developed for determination of atorvastatin in bulk and dosage form. Procedures I and II determined the drug in presence of other three statins [lovastatin, pravastatin and simvastatin] as well. Procedure I is based on formation of a highly colored ion-pair complex with methylene blue dye that was extractable in chloroform. The absorbance of the complex was measured at 654 nm against a blank. Procedure II was based on the reaction of the drug with N-bromosuccinimide [NBS] in slightly acidic media producing a yellow colored product measured at 347 nm. Procedure III depended on formation of chloroform extractable salt with silver and copper cations, while procedure IV depended on AAS measurement of copper in the chloroform extractable salt formed between the drug and copper cation. Beer's law was obeyed in the ranges of 1-12, 3-84, 10-65, 12-80 and 40-200 micro g ml[-1] for procedures I, II, Ilia, Illb and IV respectively with correlation coefficient not less than 0.9991. The four methods hold well accuracy and precision when applied to the analysis of the drug in its dosage form with percentage recoveries ranged from 99.2 +/- 0.634 to 100.53 +/- 0.227
ABSTRACT
A simple, rapid, sensitive and suitable method for analysis of etilefrineHCl [I], hexoprenaline.HCl [II], levodopa [III] and carbidopa [IV] either in pure form or in pharmaceutical formulations is described. The proposed method is based on an oxidative coupling reaction with 3-methyl-2-benzothiazolinon hydrazone hydrochloride [MBTH] in the presence of an oxidant [Ce+4 or F e+3] to give coloured species. The resulting coloures are well developed within 5 minutes at 20 +/- 5°C and stable for at least 2 hours. The gamma max were 517, 477 and 474 nm for I, II, both III and IV, respectively. A linear correlation was found between the absorbance and the concentration. Beer's law was obeyed for concentration ranges from 1-7 mg/ml, l-ll mg/ml, 1-8 mg/ml and 2-24 mg/ml for I, II, III and IV, respectively. The molar absorbtivities and Sandell sensitivities were calculated. The results of analysis of pure drugs by the proposed method are in good agreament with the official BP and USP methods. The results obtained showed recoveries of 99.80 +/- 0.27, 100.40 +/- 1.26, 99.89 +/- 0.21 and 99.96 +/- 0.36 for I, II, III and IV, in order. The proposed method was successfully applied to determine the studied drugs in their pharmaceutical dosage forms