Research Papers of ACTAVELIT
Volume : 1 | Issue : 1
Of all drug delivery systems, oral drug delivery remains the most preferred option for administration for various drugs. Oral sustained release formulations have several advantages over conventional dosage forms. These formulations improve the biological and physicochemical properties of drugs. They reduce dosing frequency, local and systemic side effects. They provide better results in shortest period of time with small quantity of drug and ensure patient compliance and convenience. There are some disadvantages of sustained release dosage form such as risk of dose dumping, rapid development of tolerance, stability problems. The aim of sustained release dosage form is slow release of a drug substance from a dosage form to maintain therapeutic response for extended period of time. Ideal condition for sustained release formulations is zero order release in which drug release is independent of the amount of drug present in the dosage form. This review describes the various factors influencing the design and performance of sustained release products and different techniques for preparing sustained release formulations. The factors influencing oral sustained release dosage forms design includes biological half life, absorption, metabolism, dose size, ionization, pka and aqueous solubility, partition coefficient, protein binding, molecular weight of the drug, stability. Different techniques for preparing sustained release formulations are encapsulation, matrix devices (dissolution control and diffusion controlled release), reservoir devices, ion exchange resins and osmotically controlled release. Sustained release pharmaceutical products have gradually gained medical acceptance and popularity. Thus sustained release dosage forms cause reduction in health care costs through improved therapy and shorter treatment period.