Introduction
Stability testing of pharmaceutical dosage forms usually begins during the
early stages of product development, the main purpose is to establish a product
shelf life. According to the long duration of room-temperature shelf lives
(may range up to several years), stability tests are often performed under stressed
conditions (e.g. elevated temperatures) to accelerate the degradation process
(Ertel and Carstensen, 1990). Garrett (Garrett, 1962) has introduced the principles
of chemical kinetic to evaluate drug stability at higher temperature. The
room-temperature stability or any lower temperature stability could be
extrapolated from accelerated data by using Arrhenius relation. The Arrhenius
equation is expressed mathematically as:
RT
E a
k Ae−
= (1)
ln k = ln A − E a RT (2)
where k is the reaction rate constant of any order, R denotes the gas constant
(1.987 calories degree-1 mole-1), A is the frequency factor, Ea is the activation
energy and T is the absolute temperature.
IntroductionStability testing of pharmaceutical dosage forms usually begins during theearly stages of product development, the main purpose is to establish a productshelf life. According to the long duration of room-temperature shelf lives(may range up to several years), stability tests are often performed under stressedconditions (e.g. elevated temperatures) to accelerate the degradation process(Ertel and Carstensen, 1990). Garrett (Garrett, 1962) has introduced the principlesof chemical kinetic to evaluate drug stability at higher temperature. Theroom-temperature stability or any lower temperature stability could beextrapolated from accelerated data by using Arrhenius relation. The Arrheniusequation is expressed mathematically as:RTE ak Ae−= (1)ln k = ln A − E a RT (2)where k is the reaction rate constant of any order, R denotes the gas constant(1.987 calories degree-1 mole-1), A is the frequency factor, Ea is the activationenergy and T is the absolute temperature.
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