The Stability of Diluted Vincristine Sulfate Used as a Deterrent to Inadvertent Intrathecal Injection

Abstract

The objective of this study was to evaluate the physical and chemical stability of vincristine sulfate diluted to a variety of concentrations in 0.9% sodium chloride injection and packaged in minibags and 30 mL syringes, to help deter inadvertent intrathecal injection of the drug. Test samples were prepared by diluting vincristine sulfate quantities of 0.5 mg, 1 mg, 2, mg, and 3 mg in 0.9% sodium chloride injection. These quantities were selected to span the range of doses normally expected for this cytotoxic drug. The vincristine was diluted with 0.9% sodium chloride injection in volumes of 25 mL and 50 mL packaged in polyvinyl chloride minibags and to 20 mL packaged in 30 mL polypropylene syringes. Physical and chemical stability evaluations were performed initially and after 1, 3, and 7 days of storage at 4°C followed by an evaluation at 9 days after 2 additional days of storage at a temperature of 23°C. Physical stability was assessed using visual observation in normal light and a high-intensity monodirectional light beam. In addition, turbidity and particle content were measured electronically. Chemical stability of the drug was evaluated by using a stability-indicating high performance liquid chromatographic (HPLC) analytical technique. No physical instability was noted and no unacceptable loss of vincristine sulfate concentration was found in any sample throughout the study period. The use of vincristine sulfate doses diluted in infusion volumes of 0.9% sodium chloride injection and packaged in minibags or in 30 mL syringes to help deter inadvertent intrathecal administration may be performed with no unacceptable physical or chemical instability occurring.