title: Microdetermination of ergocalciferol (vitamin D2) in pharmaceutical preparations by differential spectroscopy using trifluoroacetic acid in the absence of vitamin A.
abstract: A differential spectroscopy method for the determination of microgram quantities of ergocalciferol, using trifluoroacetic acid and hydrogen peroxide, was applied to commercially available pharmaceutical preparations. Tablets were powdered and extracted with methanol after being made basic with diethylamine. The methanol was concentrated, chloroform was added, and the mixture was chromatographed on neutral alumina using chloroform as the eluent. Ergocalciferol was determined in an aliquot of the eluate by differential spectroscopy and was compared with a reference ergocalciferol standard treated similarly. The method applied to low potency formulations (2.5-6 mug/tablet) is simple and quantitative, needs less than 5 hr for completion, and has a precision of less than +/- 2%. A simple and accurate chromatographic method for the determination of ergocalciferol in stabilized powders and high potency tablets, which precludes the necessity of solvent-solvent extraction, was also developed. The results are comparable with those obtained by the rat bioassay and the USP XVIII chemical assay.
mesh_terms: D000818:Animals; D002845:Chromatography; D004872:Ergocalciferols / Q000032:analysis* / Q000494:pharmacology; D005463:Fluoroacetates; D008722:Methods; D008832:Microchemistry; D051381:Rats; D013053:Spectrophotometry; D013607:Tablets / Q000032:analysis; D014269:Trifluoroacetic Acid; D014801:Vitamin A
chemical_list: D004872:Ergocalciferols; D005463:Fluoroacetates; D013607:Tablets; D014801:Vitamin A; D014269:Trifluoroacetic Acid