Simultaneous determination of the two non-steroidal anti-inflammatory drugs; Diflunisal and Naproxen in their tablets by chemometric spectrophotometry and HPLC

Chemometric spectrophotometry and HPLC were applied to the simultaneous determination of the two non-steroidal anti-inflammatory drugs; diflunisal [I] and naproxen [II]. The applied chemometric techniques are multivariate methods including classical least squares [CLS], principal component regression [PCR] and partial least squares [PLS]; and the second derivative of the ratio spectra [2Dr] method. To develop the multivariate methods, the UV absorption spectra of the standard solutions of the training and validation sets in methanol were recorded in the range of 242-274 nm at 2 nm intervals. The specificity of the studied multivariate methods has been tested. In the 2Dr method, analytical signals at 235 and 259 nm were selected for the determination of [I] and [II], respectively. The HPLC method depends on reversed-phase separation using C18 column. The mobile phase consists of a mixture of acetonitrile - acetate buffer [pH 4.2; 50 mM] [60:40, v/v]. The UV detector was set at 255 nm. The developed methods were validated and successfully applied to the simultaneous determination of [I] and [II] in their tablets. The assay results obtained using the chemometric methods were statistically compared to those of the HPLC method and good agreement was observed

Compensation methods for the spectrophotometric determination of two component mixtures using fourier to orthogonal ratio

A new method, based upon the compensation technique, was presented for the spectrophotometric determination of a mixture of two absorption compounds with overlapping spectra. Thus, using the ratios of Fourier to orthogonal function coefficients, the exact compensation of any component in the mixture was achieved with its subsequent determination. Hence, the personal judgment about the correct evaluation of the balance point was completely eliminated. The proposed method has been applied to the analysis of five two-component mixtures and the results obtained were precise and accurate

Spectrophotometric determination of isoniazid with p-benzoquinone

Interaction of isoniazid with aqueous alcoholic p-benzoquinone has been studied over the pH range 0.5-8. Absorption maxima at 298, 347, 323 and 312 nm were detected; each predominates under specific pH. At pH 1.1, the maximum at 312 nm obeys Beer's law over the range 1-10 mug/ml with apparent molar absorptivity of 2.09 x 104 1 mol-1 cm-1. The method has been successfully applied to two pharmaceutical preparations