American journal of health-system pharmacy : AJHP : official journal of the American Society of Health-System Pharmacists
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The stability of irinotecan after reconstitution in several vehicles for i.v. infusion was studied. Irinotecan hydrochloride injection was diluted in phosphate buffer solution (pH 4.0, 6.0, and 7.4), 5% dextrose injection, and 0.9% sodium chloride injection to a final concentration of 20 micrograms/mL. The solutions were stored at 25, 37, and 50 degrees C and assayed at intervals up to 24 hours by high-performance liquid chromatography for the concentration of the lactone form of irinotecan remaining. ⋯ The hydrolysis of irinotecan to its carboxylate form was reversible. The rate and extent of hydrolysis increased with increasing pH. The use of a weakly acidic vehicle, such as 5% dextrose injection, for reconstitution of irinotecan may maintain the drug's stability prior to administration.