Multicomponent spectrometric assay of cyanocobalamin and its photoproduct hydroxocobalamin in the presence of ascorbic acid in photolyzed solutions

The simultaneous determination of cyanocobalamin [CC], hydroxocobalamin [HC] and ascorbic acid [AA] in aqueous solution has been achieved by a multicomponent spectrometric method. CC undergoes photolysis in acidic and alkaline media to form HC and the reaction is enhanced in the presence of AA. The method has been used to evaluate the kinetics of photodegradation reactions of the vitamin. CC, HC and AA present in the photolyzed solutions have been determined by absorbance measurement at 550, 525 and 265 nm at pH 4.0. These wavelengths correspond to the absorption maxima of the three substances and thus provide high specificity and sensitivity to the method. The method has been validated with respect to various parameters relating to the analytical performance characteristics. The recovery of the method for the three compounds ranges from 97.1-103.0% with a RSD value of +/- 3%. The accuracy of the method is shown by the linearity of the kinetic plots in the concentration range studied. The method is simple, rapid and convenient for the proposed work

Vitamin B[6]: Deficiency diseases and methods of analysis

Vitamin B[6] [pyridoxine] is closely associated with the functions of the nervous, immune and endocrine systems. It also participates in the metabolic processes of proteins, lipids and carbohydrates. Pyridoxine deficiency may result in neurological disorders including convulsions and epileptic encephalopathy and may lead to infant abnormalities. The Intravenous administration of pyridoxine to patients results in a dramatic cessation of seizures. A number of analytical methods were developed for the determination of pyridoxine in different dosage forms, food materials and biological fluids. These include UV spectrometric, spectrofluorimetric, mass spectrometric, thin-layer and highperformance liquid chromatographic, electrophoretic, electrochemical and enzymatic methods. Most of these methods are capable of determining pyridoxine in the presence of other vitamins and complex systems in micro g quantities. The development and applications of these methods in pharmaceutical and clinical analysis mostly during the last decade have been reviewed

Determination of benzoic acid and salicylic acid in commercial benzoic and salicylic acids ointments by spectrophotometric method

Commercial benzoic acid and salicylic acid ointments have been analyzed for benzoic acid and salicylic acid content by using a spectrophotometric method. Since benzoic acid and salicylic acid exhibit overlapping spectra, absorbance measurements are made at two wavelengths, i.e. 271 nm and 303 nm in ethanol [96%v/v] for simultaneous determination of the two compounds. The method is direct and involves only one step of absorbance measurement in the assay. The precision of the method, based on the analysis of synthetic mixtures of the two compounds, is within 2%. The recoveries of benzoic acid and salicylic acid in the ointments range from 99.9 to 100.6% and 99.5 to 101.3%, respectively and are comparable with those of the USP method [99.8 to 100.5% and 100.2 to 101.7%, respectively]. The proposed method is simple, rapid, precise and convenient for the assay of benzoic acid and salicylic acid in commercial preparations

Chromatographic study of photolysis of aqueous cyanocobalamin solution in presence of vitamins B and C

Aqueous cyanocobalamin solutions [pH 1-7] have been photolysed in the presence of individual B [thiamine HCl, riboflavin, nicotinamide and pyridoxine HCl] and C [ascorbic acid] vitamins with visible light. The degraded solutions were subjected to thin-layer chromatography using several solvent systems and the Rf values of the vitamins and their photoproducts were determined. The major photoproducts have been identified by comparison of their Rf values with those of the authentic compounds. Cyanocobalamin leads to the formation of hydroxocobalamin. Thiamine HCl gives rise to 4-methyl-5-[C-hydroxyethyl] thiazole and 2-methyl-4-amino-5-hydroxymethyl-pyrimidine in trace amounts whereas riboflavin degrades extensively to formylmethylflavin and lumichrome, and to a smaller extent to lumiflavin and carboxymethylflavin. Ascorbic acid is oxidized to dehydroascorbic acid. Nicotinamide and pyridoxine HCl do not undergo any degradation. The extent of degradation depends upon the pH