Recent Research on Matrix Tablets for Controlled Release-A Review

Oral drug delivery is the leading and the oldest segment of the total drug delivery system in the market. It is the greatest growing and most favored route for drug administration so oral controlled release of drugs becomes a very promising approach for drugs that having the shorter half-life and high dose frequency. Matrix tablets are an interesting option and new break through when developing an oral controlled release drugs delivery system. The use of various classes of release rate retardants like hydrophilic, hydrophobic, polymers and their degradation products are focused also. Release of drugs from matrices formulated with hydrophobic polymers is slower than from matrices formulated with hydrophilic Polymers.

The present article contains a brief review of various formulation approaches used in controlled release drug delivery systems, the role of polymers in the controlled delivery of many fast release drugs and the mechanism of drug release from these polymeric matrices. The oral controlled release system of many drugs has been known to be an essential part of formulation development in drug delivery systems. It has been the focus of pharmaceutical research for many years due to its various advantages over conventional dosage forms. Administering the drug for release in the blood at a controlled rate, to maintain relatively constant drug levels in plasma over a controlled period of time, can overcome many problems associated with conventional dosage forms. The applicability of these dosage forms is due to reduction in the frequencies of drug dosing, which lead to patient convenience and compliance. In addition, a reduction of wide fluctuations in plasma drug concentration peak can be obtained. As a result, toxicity and poor efficacy can be avoided, especially with drugs of narrow therapeutic indices. Such problems, associated with conventional dosage forms of many drugs, can be overcome by using controlled release drug delivery systems, to deliver the drug for absorption at a controlled rate over an extended period of time. The controlled release dosage form should be tailored so that variations in the components can lead to predictable alterations in the drug release profiles. Various controlled release drug delivery systems have different mechanisms to control the drug release rate, such as the osmotic pump, ion exchange resin and matrix systems which have been widely utilized as controlled release drug delivery approaches. Besides, polymers have often been used in the components of controlled release drug delivery systems.