Determination of vitamin D 2 in gelatin-protected vitamin A acetate-vitamin D2 beadlets by high pressure liquid chromatography

Determination of potential content of vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol) in gelatin-coated beadlets, oil-based mixtures, and multivitamin tablet and capsule formulations

A high-performance liquid chromatographic procedure was used to determine routinely the potential vitamin D content in raw materials and multivitamin formulations. The method employs a microparticulate silica column to separate vitamin D from its degradation products as well as other fat-soluble vitamins. Sample preparation is simple, and the chromatographic time is less than 20 min when progesterone is added to the injection mixture as an internal standard. Replicate analyses of complex multivitamin formulations demonstrate precision with a relative standard deviation of less than 4%. Spiked placebos typically show 98--100% recovery and a linear chromatographic response. The use of bulk drug as a working reference standard is recommended for the determination of the potential vitamin D concentration in pharmaceutical multivitamin preparations.

Determination of vitamin D in foods: a review

Determining vitamin D content in foods is difficult because in natural foods of highest vitamin D activity, and even in vitamin D-fortified foods, only small quantities are present, and many other compounds are extracted along with vitamin D that cause difficulties in purifying the extract or in the spectrophotometry or colorimetry that follows. Several physicochemical methods--such as spectrophotometric, colorimetric, thin-layer chromatographic, adsorption, partition, gas-liquid, and high-performance column chromatographic--have been tried for assay foods for vitamin D, but none of them have been accepted for official or routine use; they are time consuming and expensive, or lack the required sensitivity, precision, or accuracy. Curative biological assays, based on degree of healing of a leg bone of rats previously made rachitic, is the generally accepted method to determine vitamin D content of foods. However, that method also requires too much time and is expensive. The recently developed high-performance liquid chromatographic method may offer the most for establishing a satisfactory physicochemical method for determining vitamin D in foods. Many of the difficulties and problems in assaying foods for vitamin D are discussed.

High-performance liquid chromatography determination of potential content of vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol) in resins, oils, dry concentrates and multivitamin formulations

The determination of potential vitamin D concentrations in raw materials and in multivitamin formulations by high-performance liquid chromatography is reported. Simple experimental conditions allow the rapid separation of the vitamins from their respective pro- and pre-vitamins, from their irradiation side-products and from some of their overirradiation products. Vitamin extraction is performed directly from dry concentrates, tablets and capsules, without saponification; all procedures are carried out at room temperature so as to preserve the ratio of vitamin D and pre-vitamin D present in the prepatation. The relative standard deviation is less than 1.5%.

[Determination of vitamin D3 and its isomers in D3 resins and in mixtures with vitamin A acetate (author's transl)]

Vitamin D3 and its isomers, prepared from 7-dehydrocholesterol by photochemical reaction, can be separated and quantitatively determined by high-pressure liquid chromatography on aluminium oxide using chloroform as the eluting agent. The determination of small amounts of vitamin D3 in an excess of vitamin A acetate can be achieved by the same method.