Gas chromatographic determination of histapyrrodine hydrochloride in pharmaceutical preparations.

A simple gas chromatographic method is described for the determination of histapyrrodine HCl in marketed formulations. Chlorpheniramine maleate is used as the internal standard. The amount of histapyrrodine HCl found by the proposed method averaged 19.91 mg/tablet, compared with the label claim of 20 mg/tablet. The method was statistically evaluated for accuracy and precision.

Simple colorimetric method for determination of thiamine hydrochloride in pharmaceuticals.

A simple colorimetric method is described for the determination of thiamine hydrochloride (vitamin B1) in dosage forms. The method is based on measurement of a yellow complex formed when thiamine HCl is treated with p-methylaminophenol sulfate (Metol) under alkaline conditions. Compounds such as vitamins A, B2, B6, B12, C, D, and E, and niacinamide, citric acid, liquid glucose, calcium pantothenate, biotin, liver extract, and folic acid do not interfere in the reaction. Extracting the complex into chloroform before quantitation enhances the stability of the reaction product and removes interference of water-soluble colored constituents in syrup samples. Statistical validation shows that the method is precise and accurate. Results agree well with those obtained by other methods in the literature.

Simple colorimetric method for determination of metaproterenol sulfate in pharmaceuticals.

A simple colorimetric method is described for the determination of metaproterenol sulfate (orciprenaline sulfate). The method is based on measurement of a colored species formed when metaproterenol sulfate is treated with diazotized dapsone, p-nitroaniline, or benzocaine at room temperature, followed by treatment with an aqueous solution of trimethylamine in the case of benzocaine. Compounds such as starch, talc, and common excipients do not interfere in the reaction. Statistical validation showed that the method was precise and accurate. The results agree well with those obtained by other methods reported in the literature.

Simple colorimetric method for determination of pyridoxine hydrochloride (vitamin B6) in pharmaceuticals.

A simple colorimetric method is described for the determination of pyridoxine hydrochloride (vitamin B6). The method is based on the measurement of an orange species formed when pyridoxine hydrochloride is treated with diazotized dapsone and sulfanilamide in a mixture of trichloroacetic acid and sulfuric acid at room temperature, followed by treatment with an aqueous solution of sodium carbonate. Compounds such as thiamine hydrochloride, cyanocobalamin, and common excipients such as starch and talc which are present in various formulations with pyridoxine hydrochloride do not interfere in the reaction. Statistical validation showed that the method was highly precise and accurate. Results agree well with those obtained by other methods reported in the literature.