Microdetermination of ergocalciferol (vitamin D2) in pharmaceutical preparations by differential spectroscopy using trifluoroacetic acid in the absence of vitamin A.
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.
Studies on the isomerization of vitamin D and related compounds with acidic reagents. II. Mechanism of the isomerization of vitamin D2 and its isomers with boron trifluoride.
Kinetic experiments on the isomerization of vitamin D2, pre-D2, 5, 6-trans-D2 and T2 with BF3 were investigated by using the determination method as reported previously (1). The related components in the reaction mixtures were confirmed to be one of the starting compounds, iso-D2 and iso-T2 in all cases by applying the qualitative method using both TLC and GLC. Then, the components were individually determined by the proposed method according to lapse reaction times. The con-version rates of all the starting compounds followed apparent first-order kinetics and the rate constants of vitamin D2, pre-D2, 5, 6-trans-D2 and T2 were 0.277, 0.462, 0.693 and 0.330, respectively. When the yields of iso-D2 and iso-T2 to the concentrations of converted starting compounds were calculated on the basis of the corresponding reaction times, the initial rates of yields of iso-D2 and iso-T2 at zero conversions of the starting compounds were respectively 100 and 0% in all cases. The results induced the conclusions in all cases that iso-D2 was originated as the first reaction product directly from the starting compounds while iso-T2 was the second reaction product originated via iso-D2. The conclusions are summarized as follows: Vitamin D2, pre-D2, 5, 6-trans-D2 or T2 →BF3 iso-D2 →BF3 iso-T2 The reaction mechanism was discussed from the conclusions (Fig. 4).
VITAMIN D AND CARDIOVASCULAR, RENAL, AND BRAIN DAMAGE IN INFANCY AND CHILDHOOD
There has been increasing notice taken in the literature of recent years of a presumed congenital abnormality characterized by supravalvular aortic stenosis, a peculiar facies and severe mental retardation. That an hereditary genetic defect may play a part in this syndrome has been suggested. The possibility that this syndrome may be induced by excess vitamin D during gestation has also been considered. This paper presents the possibility that this syndrome is an expres9ion of hyper-reactivity to vitamin D that can be especially severe during early infancy. There is evidence that it may be the anatomic consequence of the disease known as hypercalcemia of infancy, which many investigators have found to develop in infants receiving doses of vitamin D that are only slightly to moderately above those considered prophylactic. This paper presents evidence that generalized arteriosclerosis of infancy may be the most severe manifestation of vitamin D toxicity in infants with marked susceptibility to vitamin D, and that renal acidosis may be a less severe expression of this sensitivity. There is evidence that recommended daily dosages of vitamin D may be toxic for some susceptible people, and that the potency of vitamin D is significantly greater in milk than in oil. As Taussig’ has recently observed, the inborn “variant” in the metabolism of vitamin D that made some children less prone to rickets in the days before unlimited vitamin D supplementation of our foods is now the socalled “inborn error of metabolism” that may be responsible for vitamin Dinduced injury to the cardiovascular, renal, and central nervous systems.