Your Compounding Questions Answered
Author: Martin A. Erickson III, RPh
Q: I have been asked to make a propylene glycol-free vitamin D3 concentrated formula for a children’s hospital. The dietitian wants a dose of 50,000 units.
A: Vitamin D3, or cholecalciferol, occurs as almost-white to white odorless crystalline needles. It is practically insoluble in water; soluble in the alcohol, acetone, chloroform, and ether; and slightly soluble in vegetable oils. It is oxidized and inactivated in moist air within a few days, but if stored in amber evacuated ampules at refrigerated temperature, it exhibits negligible deterioration after 1 year. One unit of vitamin D is contained in 25 ng of cholecalciferol and 25 ng of ergocalciferol.
Use caution when administering to infants, because of possible hypersensitivity of the patient to its effects and the risk of hypercalcemia. Cholecalciferol and ergocalciferol are well absorbed from the gut and hydroxylated in the liver to form calcifediol and 25-hydroxyergocalciferol, which further undergo hydroxylation in kidneys to form the active metabolites calcitriol and 1,25-dihydroxyergocalciferol.
Some possible formulations of concentrated vitamin D3 solutions require facilities and methods that are out of the scope of today’s average pharmacist. The United States Pharmacopeia give ergocalciferol oral solution as “[containing] ergocalciferol in an edible vegetable oil, polysorbate 80, or in propylene glycol; it is stored in airtight containers.” The commercially manufactured product containing calcitriol is based on palm seed oil, which could be a basis for an extemporaneously compounded cholecalciferol oral solution. An oral liquid containing vitamin D3 for treatment of Raynaud’s disease was given as:
Zinc, Magnesium, Calcium, and Vitamin D3 Oral Liquid (100 mL)
Zinc gluconate, 2.32 gm
Magnesium oxide, 2.77 gm
Calcium phosphate dibasic, 37.16 gm
Vitamin D3, 4320 IU
Polysorbate 80, 2 mL
Glycerin, 20 mL
Methylparaben, 0.200 gm
Purified water USP qs ad, 100 mL
Mr. Erickson is director of professional affairs at Gallipot Inc.