Abstract
he release of drug from the formulations plays significant role especially when it comes to modified release as well as in immediate release dosage forms. Several factors like physicochemical properties of drugs, excipients, dosage form design, manufacturing process variables and design impact drug release from dosage form.It is essential to study the release pattern of drug from dosage form as it governs the efficacy of the dosage form. Several models facilitate the understanding of release pattern thus enabling to design an effective formulation. A few of the various models used by researchers to study the release profile are explained in this review which includes: Higuchi model -describes the drug release from a matrix system. Hixson-Crowell cube root law -describes the release from systems where there is a change in surface area and diameter of particles. Korsmeyer and Peppas developed an empirical equation to analyze both Fickian and non-Fickian release of drug from swelling and nonswelling polymeric delivery systems. Baker and Lonsdale developed the model from Higuchi model explaining the drug release from spherical matrices. The Weibull equation which describes drug dissolution and release from dosage forms, it expresses the accumulated fractio n of drug‘m’ in solution at time‘t’. Hopfenberg model correlates the drug release from surface eroding polymers. The exponential model known as Gompertz model which describe in-vitro dissolution profile. The Gallagher and Corrigan model which describes the fraction of drug released from the biodegradable polymeric system. The Cooney model which describes about spheres and cylinders undergoing surface erosion.

Key words: Release kinetics; Release models; Dissolution; mathematical modeling