Effect of β-Cyclodextrin on the Degradation Rate of Cinnarizine in Aqueous Solution

The degradation kinetics of cinnarizine in aqueous solution containing β-cyclodextrin at pH 1.20 and four different temperatures were investigated. The degradation of cinnarizine was found to be a pseudo first-order reaction. The pseudo first-order rate constant with β-cyclodextrin decreased with increase in the concentration of β-cyclodextrin at pH 1.20. From Arrhenius plots, the values of activation energy of the degradation in aqueous solution at pH 1.20 containing 3.26×10-3 and 15.32×10-3 M β-cyclodextrin were calculated to be 37.0 kcal/mol and 40.1 kcal/mol, respectively.