From the information on chemical kinetics it is possible to accurately study the degradation of an active drug in solution, as well as determine the mechanism responsible for the degradation.A more complicated situation arises when an attempt is made to study stability of one or more drugs in liquid pharmaceutical dosage forms.Because of the multiplicity of ingredients in most pharmaceutical formulations,there exists the possibility of of interactions that take place, as well as each ingredient having different degradative characteristics.The ideal situation should be to study the degradation pattern of each in mixture individually. This of course is difficult,time consuming and expensive to accomplish.Fortunately it is not necessary for the purpose of stability prediction to determine the mechanism of degradation,since generally it is possible to evaluate the stability of any component of a pharmaceutical preparation by determining some property of the degradation as a function of time.