Folic acid, USP, N-[p-[[(2-amino-4- hydroxy-6-pteridinyl) methyl]- amino] benzoyl]-Lglutamic acid, is a B complex vitamin containing a pteridine moiety linked by a methylene bridge to para-aminobenzoic acid, which is joined by a peptide linkage to glutamic acid. Conjugates of folic acid, USP are present in a wide variety of foods, particularly liver, kidneys, yeast, and leafy green vegetables. Commercially available folic acid, USP is prepared synthetically. Folic acid, USP occurs as a yellow or yellowish-orange crystalline powder and is very slightly soluble in water and insoluble in alcohol. Folic acid, USP is readily soluble in dilute solutions of alkali hydroxides and carbonates, and solutions of the drug may be prepared with the aid of sodium hydroxide or sodium carbonate, thereby forming the soluble sodium salt of folic acid, USP (sodium folate). Aqueous solutions of folic acid, USP are heat sensitive and rapidly decompose in the presence of light and/or riboflavin; solutions should be stored in a cool place protected from light.
The structural formula of folic acid, USP is as follows:
C 19H 19N 7O 6 M.W. 441.40
Each tablet, for oral administration, contains 1 mg folic acid, USP.
Folic acid tablets, USP 1 mg contain the following inactive ingredients: lactose monohydrate, microcrystalline cellulose, sodium starch glycolate and stearic acid.