Oral drug delivery systems most preferred option of administration for various drugs. Sustained release drug delivery system is the novel drug delivery system. The terms Sustained release, prolonged release, modified release, extended release or depot formulation are used to identified drug delivery systems that are designed to achieve or extend therapeutic effect by continuously releasing medication over an extended period of time after administration of a single dose. Sustained release dosage forms are designed to release a drug at a predetermined rate by maintaining a constant drug level for a specific period of time with minimum side effects. The basic rationale of sustained release drug delivery system optimizes the biopharmaceutical, pharmacokinetics, and pharmacodynamic properties of a drug in such a way that it’s utility is maximized, side effects are reduced and cure of the disease condition is achieved. Sustained release drug delivery is improved patient compliance due to less frequent drug administration, reduction of fluctuation in steady-state drug levels, maximum utilization of the of the drug, improved therapy and shorter treatment period.