Relationship between compression pressure, mechanical strenghth and release properties of tablets.

Tablets are a complex drug delivery system consisting of the active pharmaceutical ingredients and excipients. Tablet production involves a series of unit operations in which drugs and excipients are subjected to mechanical stresses, such as compression pressure, thus imposing changes in the properties of these materials. Variations in the compression pressure and other processing parameters may affect the mechanical strength and release properties of the final tablet. It is generally expected that an increase in compression pressure should lead to an increase in mechanical strength and a decrease in release properties of tablets, but this may not be true in some practical situation, since tablet production is the result of complex interaction between many factors involving the drug, excipient, the formulation, and processing variables. The degree and extent of interaction of these variables are not absolutely dependent on one factor. The aim of this review is to study the interaction between compression pressure, mechanical strength and release properties of immediate and controlled release tablets. The effect of compression pressure on tablets is complemented by such factors as the material properties of the drug and excipient, the formulation and processing factors, which in turn affects mechanical strength and release properties.