In last decade, considerable efforts were made on determining kinetic models of drug delivery systems to emphasize the order of release profile. Whenever a new dosage form is designed or fabricated, it is necessary to ensure that drug dissolution occurs in an appropriate manner. Relatively, quantitative results of the values obtained in dissolution/release tests is easier than kinetic equations that express the dissolution profiles as a function of some of the delivery systems characteristics

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... e used. In some cases, these kinetic models are derived from the theoretical analysis of the occurring process. In most of the cases the theoretical concept does not exist and some empirical equations have proved to be more appropriate. Drug dissolution from delivery systems has been described by kinetic models in which the dissolved amount of drug (Q) is a function of the test time, t or Q=f(t). Some commonly used, analytical definitions of the Q(t) function are such as zero order, first order, Hixson-Crowell, Weibull, Higuchi, Baker-Lonsdale, Korsmeyer-Peppas, and Hopfenberg models. Other release parameters, such as dissolution time (t ), assay time (t ), dissolution efficacy (ED), difference factor ( f ), x% x min 1 similarity factor ( f ) and Rescigno index (j and j ) can be used to characterize drug dissolution / release profiles.