Studies of Degradation Kinetics of a 5-HT3 Antagonist, Ramosetron Hydrochloride: Effects of Temperature

Abstract

Ramosetron hydrochloride is the hydrochloride salt of ramosetron, a selective serotonin (5-HT3) receptor antagonist with potential antiemetic activity. Upon administration, ramosetron selectively binds to and blocks the activity of 5-HT subtype 3 (5-HT₃) receptors located in the vagus nerve terminal and the vomiting center of central nervous system (CNS), suppressing chemotherapy-induced nausea and vomiting. Degradation of Ramosetron HCl was conducted with 0.1N NaOH at 60^°C, 70^°C and 80^°C to study the reaction kinetics. The reaction rate constants (k) for degradation at 60^°C, 70^°C and 80^°C were -2.2680 molL^-1s^-1 , -3.3714 molL^-1s^-1 and -5.3686 molL^-1s^-1 for zero order and -1.05 x 10^-2s^-1, -1.60 x 10^-2s^-1 and -2.70 x 10^-2s^-1 for first order kinetics, respectively. The activation energy of Ramosetron HCl was found as 10.05 kcalmol^-1 by using Arrhenius equation.

Dhaka Univ. J. Pharm. Sci. 17(2): 167-173, 2018 (December)