Analysis of paracetaiiviol and ascorbic acid in pharmaceutical binary mixture

Two simple and sensitive spectrophotometric methods were developed for the determinagion of paracetamol [I] and ascorbic acid [II] in pharmaceutical binary mixture. The first method depends on the use of the first-derivative spectrophotometric technique for the slinultaneons determination of components of the mixture. The second method depends on the reaction of the studied drugs with 5-diazo-1, 2, 4-triazol-3-carboxylic acid [DTCA] reagent to give colored products measured at 480 nm and 580 nm for [I] and [II] respectively. All variables affecting reaction conditions were optimized The proposed methods were successfully applied for the analysis of the studied drugs in their pare and commercial dosage forms and are in good agreement with those obtained from the reported methods. No significant difference in the acuracy and precision as revealed by the accepted values of t- and F-tests, respectively. Molar ratios of the drugs with the colorimetric reagent [DTCA] were determined and the reaction mechanisms were suggested

Utility of certain spectrofluorimetric methods for analysis of two pharmaceutical binary mixtures

Simple and very sensitive spectrofluorimetric methods were developed for determination of adrenaline [I] -procaine hydrochloride [II] mixture and salbutamol sulfate [III] - guaifenesin [IV] mixture. adrenaline [I] in the first mixture was determined by coupling with 5-diazo-l,2,4-triazolo-3-carboxylic acid [DTCA] reagent in alkaline medium forming fluorigenic product which can be measured at 340 nm [lambda ex. 245 nm], while procaine hydrochloride [II] gave no fluorescence. salbutamol sulfate [III] was analyzed by reaction with ethyl acetoacetate [eaa] forming coumarin derivative, which can be measured at 320 nm lambda ex. 280 nm]. guaifenesin [iv], the second drug in mixture has a considerable native fluorescence in methanol was measured at 310 nm [lambda ex. 230 nm]. all variables affecting reaction conditions were optimized. linear correlations were obtained over the range of 19-100, 37-400 and 22-150 ng/ml for [I], [III] and [IV], respectively. the proposed methods were successfully applied for the analysis of the studied drugs in their pure and commercial dosage forms and the obtained results were in good agreement with those obtained from the reported methods; no significant difference in the accuracy and precision as revealed by the accepted values of t-and f-tests, respectively

Spectrophotometric determination of certain drugs using ammonium cerium [IV] sulfate and p-dimethylaminobenzaldehyde

A spectrophotometric method for the determination of acetylcysteine, captopril carbimazole propylthiouracel and thiopental sodium is described. The method was based on the oxidation of the studied drugs with excess ammonium cerium [IV] sulfate. Followed by measuring the excess unreacted ammonium cerium [IV] sulfate, through reaction with p-DMAB into the corresponding p-dimethylaminobenzoquinone, which has a red colour can be measured at 464 nm. The decrease in the absorption intensity at 464 nm caused by the presence of the investigated drugs is directly proportional to their concentration. Investigations were carried out to study all variables and a validation study for the proposed procedure according to USP 2002 was also performed. Beer's law was obeyed in the range of 1-40 micro.g/ml. The detection limit ranged from 0.22-1.22 micro g/ml, while the quantitation limit ranged from 0.73-4.06 micro g/ml. The proposed method was successfully applied for the analysis of the studied drugs in pharmaceutical preparations with good recoveries in the range of 98.12-100.02%. Results were compared with those obtained from the pharmacopoeial or reported methods