The aquation of oxaliplatin and the effect of acid

AimTo investigate the aquation of oxaliplatin in aqueous solution at different temperatures and gain the kinetic data. MethodsElectronic conductometry and high performance liquid chromatography (HPLC) were used to measure the oxaliplatin content in the reaction systems at different time. ResultsThe aquation of oxaliplatin followed a pseudo-first-order rate law. In the absence of H⁺, the observed rate constant kobs was 7.76×10^-6·min^-1 and the half life t_1/2 was 62 days at 25 ℃. In the presence of H⁺, the aquation could be accelerated by H⁺according to the equation k_obs=(2.61+21.9［H⁺］)×10^-4·min^-1. The mechanism of aquation has also been proposed in this paper. From the mechanism, the rate of aquation following to r=(k₁k₂)［L-OHP］/k-1 in the absence of H⁺ and r=(k₁+k0k₃［H⁺］)［L-OHP］ in the presence of H⁺ have been deduced, which were in perfect agreement with the experimental results. Conclusion In the absence of H⁺, the aqueous solution of oxaliplatin is stable, which meets to the request of clinical.