UV derivative spectrophotometric study of the photochemical degradation of nisoldipine.

The photodecomposition of nisoldipine ((+/-)3-isobutyl-5-methyl-1,4- dihydro-2,6-dimethyl-4-(2-nitrophenyl)-pyridine-3,5-dicarboxylate), whereby its 4-(2-nitrosophenyl) pyridine analogue is obtained as the photolytic product, was investigated under daylight exposure by means of UV derivative spectrophotometry. The optimal instrumental parameters (120 nm/min scan speed; 2 nm slit width; delta gamma = 10 nm and 5 s response time) for analogue derivative spectra were established for amplitudes 1D285 and 2D291 (measured to the baseline) of the nitroso analogue assay, as well as for 1D386 of the parent compound-nisoldipine assay. Using the first-order derivative spectrum, the minimum detectable amount of nitroso analogue in the presence of nisoldipine was equivalent to an impurity level of 5% and by the second-order derivative spectrum, the determination limit was equivalent to an impurity level of 2%.

Quantitative analysis of sulpiride and impurities of 2-aminomethyl-1-ethylpyrrolidine and methyl-5-sulphamoyl-2-methoxybenzoate in pharmaceuticals by high-performance thin-layer chromatography and scanning densitometry.

A simple and reliable thin-layer chromatographic method for determining sulpiride and impurities of 2-aminomethyl-1-ethylpyrrolidine and methyl-5-sulphamoyl-2-methoxybenzoate was developed and validated. A methylene chloride-methanol-ammonia solution (25%; 18 + 2.8 + 0.

HPTLC determination of ceftriaxone, cefixime and cefotaxime in dosage forms.

The objective of this investigation was to develop a HPTLC method for the determination of ceftriaxone, cefixime and cefotaxime, cephalosporins widely used in clinical practice. High performance TLC of cephalosporins was performed on pre-coated silica gel HPTLC plates with concentrating zone (2.5 x 10 cm) by development in mobile phase ethyl acetate-acetone-methanol-water (5:2.

HPTLC assay of cephalexin and cefaclor in pharmaceuticals.

A simple and reliable HPTLC method for the simultaneous determination of cephalexin and cefaclor is developed and validated. The methanol-ethyl acetate-acetone-water (5:2.5:2.

Gas chromatography-mass spectrometry determination of isosorbide 5-mononitrate and related impurities in raw materials and dosage formulations.

A straightforward quantitative method for gas chromatography-mass spectrometry determination of isosorbide 5-mononitrate (IS5MN) and its related impurities such as isosorbide (IS), isosorbide diacetate (ISDA) and isosorbide 2-acetate-5-nitrate (IS2A5N) in raw materials as well as in dosage formulations is developed. The recovery of these materials was found to be 100.4 +/- 2.