Studies of Degradation Kinetics of a 5-HT3 Antagonist, Ramosetron Hydrochloride: Effects of Temperature
Keywords:
Degradation kinetics, reaction rate constant, activation energy, half-life, shelf-life.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.
