Abstract: The disclosure provides compositions, methods, and devices for use in delivering Mitomycin-C(MMC), an antineoplastic chemotherapy drug often used for bladder instillations to treat bladder cancer, which degrades in both acidic and alkaline environments. The disclosure provides a solution of buffered MMC (or a different drug) in 50% propylene glycol that maintains a pH from 7.0 to 8.0 when introduced into acidic solutions (pH of 5.0) and is stable when stored at 2-8° C. for greater than 134 days. This formulation can be produced in an FDA registered 503B Outsourcing facility in a pre-filled, ready-to-administer syringe kit with pre-attached closed system transfer device and accessories required for bladder instillation.