@Narendrajha Rate of chemical reactions depends upon the temperature. At higher temperatures, the probability that two molecules will collide is higher. This higher collision rate results in a higher kinetic energy, which has an effect on the activation energy of the reaction. The activation energy is the amount of energy required to ensure that a reaction happens.
More reaction in products will cause more degradation in pharmaceutical products.
Quantitatively this relationship between the rate a reaction proceeds and its temperature is determined by the Arrhenius Equation.