DESCRIPTION
DRISDOL, brand of ergocalciferol capsules, USP, is a synthetic calcium regulator for oral administration.
Ergocalciferol is a white, colorless crystal, insoluble in water, soluble in organic solvents, and slightly soluble in vegetable oils. It is affected by air and by light. Ergosterol or provitamin D2 is found in plants and yeast and has no antirachitic activity.
There are more than 10 substances belonging to a group of steroid compounds, classified as having vitamin D or antirachitic activity.
One USP unit of vitamin D2 is equivalent to one International Unit (IU), and 1 mcg of vitamin D2 is equal to 40 IU.
Each capsule contains 1.25 mg (50,000 International Units vitamin D) of ergocalciferol, USP, in an edible vegetable oil.
Ergocalciferol, also called vitamin D2, is 9,10-secoergosta-5,7,10(19),22-tetraen-3-ol,(3ß,5Z,7E,22E)-; (C28H44O) with a molecular weight of 396.65, and has the following structural formula:
Inactive Ingredients:FD&C Blue #1, FD&C Yellow #5, Gelatin, Glycerin, Soybean Oil.
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CLINICAL PHARMACOLOGY
The in vivo synthesis of the major biologically active metabolites of vitamin D occurs in two steps. The first hydroxylation of ergocalciferol takes place in the liver (to 25-hydroxyvitamin D) and the second in the kidneys (to 1,25-dihydroxyvitamin D). Vitamin D metabolites promote the active absorption of calcium and phosphorus by the small intestine, thus elevating serum calcium and phosphate levels sufficiently to permit bone mineralization. Vitamin D metabolites also mobilize calcium and phosphate from bone and probably increase the reabsorption of calcium and perhaps also of phosphate by the renal tubules.
There is a time lag of 10 to 24 hours between the administration of vitamin D and the initiation of its action in the body due to the necessity of synthesis of the active metabolites in the liver and kidneys. Parathyroid hormone is responsible for the regulation of this metabolism in the kidneys.
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