INFLUENCE OF TEMPERATURE AND SHAKING ON STABILITY OF INSULIN PREPARATIONS - DEGRADATION KINETICS

Two commercial human insulin preparations were stored at different con ditions in order to study the influence of temperature and shaking on their stability. Deamidation was the predominant degradation process i n the case of the suspension, while dimerization prevailed for the sol ution, mainly when shaking was applied. The formation process of desam ido B3 insulin follows first order kinetics; the dimer formation fit b etter the Prout-Thompkins nucleation model. Results obtained for suspe nsion confirm the suitability of Arrhenius plot for both storage condi tions. However, in the case of solution, the Arrhenius relationship wa s only valid when it was stored without shaking, since with shaking no linearity was observed in the temperature range studied.