FACTORS INFLUENCING THE DISSOLUTION TESTING OF DRUGS

ABSTRACT The efficacy of various dosage forms (e.g. tablet, etc.) rely profoundly on the dissolution rate before their absorption and becoming available to the target site. Therefore, much importance is given to dissolution testing in pharmaceutical industry. A number of factors have been identified that can influence or alter the dissolution of a particular dosage form both in vitro and in vivo. To overcome this difficulty, various strategies have been adopted in order to standardize the dissolution testing of drugs. This review highlights various factors that affect the rate of dissolution of drugs associated with the physicochemical properties, formulation, type of dosage form, device used and other factors such as food effect, etc. Keywords : Dissolution test, drug release, bioavailability, in vitro-in vivo correlation. Received: October 27, 2012 Accepted: December 10, 2012 *Author for Correspondence: sanaghayas7@hotmail.com INTRODUCTION Oral dosage form of tablets or capsules are one of the most effective ways of current treatment. The efficacy of such dosage forms is dependent on the dissolution of the drug in the gastrointestinal fluids prior to absorption into the systemic circulation; therefore, the rate of dissolution of the tablet or capsule is critical. Dissolution can be defined as the amount of drug substance that goes into solution per unit time under standardized conditions of liquid/solid interface, temperature and solvent composition (Arthur A. Noyes and Willis R, 1897). It is well thought-out as one of the most important quality control tests performed on pharmaceutical dosage forms. It is also developed as a predictor bioavailability, replacing human studies to establish bioequivalence (Itiola O.A and Pilpel N, 1996) (Raghow G and Meyer M.C, 1981) (Guidance for Industry, August 1997). A direct relationship between in vitro dissolution rate of several drugs and their bioavailability has been established and is known as in vitro-in vivo correlation, IVIVC (Amidon GL et al, 1995). In spite of IVIVC, dissolution is a qualitative and quantitative tool which can offer important information about biological availability of a drug and also lot-to-lot consistency of products (Siewert M et al, 2003) (Abdou HM, 1986). Hence, dissolution tests are used for the conformity with compendial specifications and are also required for the license application of the product. Moreover, they are used during the development and stability testing as part of product specifications (Odeku OA, 2005-2007).