[Study on index for formulation optimization of sustained or controlled released dosage forms].

Release in vitro is one of the indexes for quality control of solid dosage forms. It is not only the important indexes for evaluation of bioequivalence, also the important parameter of formulation optimization, study of the stability and quality control within producing of sustained or controlled release dosage forms. The review is the study on index for formulation optimization of sustained or controlled released dosege forms in China since 1999, including the application of similarity factor and deviation.