Sulfuric acid Vinblastine sulfate

Wear rubber gloves, protective clothing, and goggles. Work in the fume hood. To 10 mL of an aqueous solution containing 10 mg of vinblastine sulfate, add 10 mL of 6 M sulfuric acid (3.4 mL of concentrated sulfuric acid slowly added to 6.6 mL of cold water). Add potassium permanganate (1 g). Continue stirring for 2 hours. Neutralize the solution by the slow addition of soda ash or 10% sodium hydroxide solution, and then add, while stirring, a saturated aqueous solution of sodium bisulfite (approximately 1 g of sodium bisulfite per 3.5 mL of water) until a colorless liquid is formed. Wash into the drain with water.3,4... 

Formation of a deep rose color when vinblastine sulfate is heated in a solution consisting of 35 ml. of pyridine, 1 ml. of concentrated sulfuric acid, and 35 ml. of acetic anhydride containing 0.05 acetyl chloride, is the basis of an assay method reported13 for relatively pure vinblastine sulfate. The reaction is carried out at 80°C. for 20 minutes. 

Mix 0.5 mg vinblastine sulfate with 5 mg of 4-dimethylamino-benzaldehyde and 0.2 ml of glacial acetic acid and 0.2 ml of sulfuric acid a reddish-brown color is produced. Add 1 ml of glacial acetic acid the color changes to pink. 

A colorimetric method was first deviced for the assay of pure vinblastine sulfate ( 107). The method depends on the formation of a deep rose color upon heating vinblastine sulfate at 80" with a reagent consisting of pyridine (35 ml), concentrated sulfuric acid (1 ml) and acetic anhydride (35 ml) containing 0.05% acetyl chloride. The color so produced is measured at 574 nm. 

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