SPL Set ID: 9ffe79a1-ac91-4a7b-a9e3-7c84bfa9ddf0

Azathioprine Sodium for Injection, USP is a sterile lyophilized material, which when reconstituted with Sterile Water for Injection yields a solution for intravenous administration. Each vial contains azathioprine sodium equivalent to 100 mg azathioprine, an immunosuppressive antimetabolite. Each vial also contains sodium hydroxide and, if necessary, hydrochloric acid to adjust the pH. Azathioprine is chemically 6-[(1-methyl-4-nitroimidazol-5-yl)thio]purine. The structural formula of azathioprine sodium is: Molecular Formula: C 9 H 7 N 7 O 2 SNa Molecular Weight: 300.28 It is an imidazolyl derivative of 6-mercaptopurine and many of its biological effects are similar to those of the parent compound. Azathioprine is insoluble in water, but may be dissolved with addition of one molar equivalent of alkali. The sodium salt of azathioprine is sufficiently soluble to make a 10 mg/mL water solution which is stable for 24 hours at 59° to 77°F (15° to 25°C). Azathioprine is stable in solution at neutral or acid pH but hydrolysis to mercaptopurine occurs in excess sodium hydroxide (0.1N), especially on warming. Conversion to mercaptopurine also occurs in the presence of sulfhydryl compounds such as cysteine, glutathione and hydrogen sulfide. Structural Formula