UV derivative spectrophotometric determination of trimethoprim in combination with sulfamethoxazole

A sensitive, rapid and well reproducible first derivative spectrophotometric method has been developed for the simultaneous determination of sulphamethoxazole in combination with trimethoprim in tablet form. By measuring the absolute value of the first derivative curves at zero contribution of the sulphonamide to trimethoprim or the opposite. The direct UV measurements were found to be unsuitable in such case due to the absorbance interference in the zero order spectra. The procedure doses not require any separation steps or sophisticated calculations. The method was successfully applied to commercial tablets containing the mixture

Application of GLC in the determination of cough-sedative mixture containing phenylephrine hydrochloride, phenylpropanolamine hydrochloride, chlorpheniramine maleate and noscapine

A GLC method was described for the quantitative determination of phenylephrine hydrochloride, phenylpropanolamine hydrochloride, chlorpheniramine maleate and noscapine. The sample of the syrup was diluted with water followed by the addition of the internal standard, alkalinization of the aqueous solution and finally extraction with chloroform. An aliquot of the chloroformic extract was brought to dryness and then treated with 4-[dimethylamino] pyridine in pyridine- acetic anhydride mixture. The four components were isolated and measured by applying 1 ul of the reaction mixture to a chromatograph equipped with a flame ionization detector and fitted with HP-1 capillary column. Codeine phosphate was used as internal standard. The results were compared statistically with a published multisteps colorimetric procedures

Determination of indomethacin in the presence of its alkaline-induced degradation products using first-derivative spectrophotometry

A rapid and direct method for the determination of indomethacin in the presence of its alkaline induced degradation products using first- derivative spectrophotometry is presented. By measuring the absolute value of the first derivative curve at the zero contribution of the degradation products [1D 340 nm], the concentration of the intact drug can be calculated directly without interference of the degradation products. Beer's law was obeyed, for intact indomethacin, in range of 2-12 mg%. The method was proved using two sets of synthetic mixtures of the intact drug with its degradation products. The mean percentage recovery was 100.2 + ' 0.86 and 99.9 =0.74, respectively. The producer is simple, rapid and allows for accurate and precise results