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Pharmacology: Vitamin C, a water-soluble vitamin, is essential for the synthesis of collagen and intercellular material. Its deficiency develops when the dietary intake is inadequate. It is rare in adults, but may occur in infants, alcoholic, or the elderly. Deficiency leads to the development of a well-defined syndrome known as scurvy. This is characterized by capillary fragility, bleeding (especially from small blood vessels and the gums), anemias, cartilage and bone lesions, and slow healing of wounds.
Pharmacokinetics: Vitamin C as Sodium Ascorbate is readily absorbed from the gastro-intestinal tract and is widely distributed in the body tissues. Plasma concentration of Vitamin C rise as the dose ingested is increased until a plateau is reached with doses of about 90 to 150 mg daily. Body stored of vitamin C in health is about 1.5 g although larger stores may occur with intake higher than 200 mg daily. The concentration is higher in leucocytes and platelets than erythrocytes and plasma. In deficiency state the concentration in leucocytes declines later at a slower rate, and has been considered to be a better criterion for the evaluation of deficiency than the concentration in plasma.
Vitamin C is reversibly oxidized to dehydroascorbic acid; some is metabolized to ascorbate-2-sulphate, which is inactive, and oxalic acid which are excreted in the urine. Vitamin C in excess of the body's needs is also rapidly eliminated in the urine; this generally occurs with intakes exceeding 200 mg daily. Vitamin C crosses the placenta and is distributed into breast milk. It is removed by hemodialysis.
