eng Science and Education Publishing American Journal of Pharmacological Sciences 2327-672X 2015-12-18 3 5 103 109 10.12691/ajps-3-5-1 AJPS2015351 article Muhammad U. Ghori 1 Barbara R Conway b.r.conway@hud.ac.uk 1 Department of Pharmacy, University of Huddersfield, Queensgate, Huddersfield, UK, HD1 3DH Oral controlled drug delivery has gathered tremendous attention over the years due to its many advantages over conventional dosage forms. Polymer-based matrices have become an integral part of the pharmaceutical industry. Hydrophilic matrices are capable of controlling the release of drug over an extended period of time. Hydrophilic polymers, especially the hydrophilic derivatives of cellulose ethers, are frequently used for these applications. Therefore, the objective of this review is to discuss the scientific and physicochemical aspects of these polymeric systems that can affect the drug release from such formulations. http://pubs.sciepub.com/ajps/3/5/1/ajps-3-5-1.pdf hydrophilic matrices hyromellose methylcellulose matrix swelling matrix erosion