Development of a pharmaceutical product is essentially a technique where in physicochemical properties of an active ingredients, excipients and manufacturing process are manipulated to achieve desired qualities in pharmaceutical finished dosage form. Certain goals such as product specifications, ease of manufacturing cost etc are defined for a dosage form prior to initiating the development work. The traditional trial and error approach may be less dependable and more time consuming and often provides an approximately or marginally acceptable formulation and process. In today's market optimization requires skill in understanding physicochemical properties of their materials and effect on the process identification and independent (cause) and dependent(effective) variables and understanding of expected relationship between cause and effect is crucial to the success of this approach.

The use of polymeric matrix devices to control the release of variety of therapeutic agents has become increasingly important in development of the modified release dosage forms. The device may be a swellable, hydrophilic monolithic systems, an erosion controlled monolithic system or a non erodible system. The initial burst release of 5-Fluoruracil from such matrix tablet surface can be controlled by compression coating technology. Appropriate combination of hydrophilic polymer in upper and lower layer of tablet can govern the release of 5-fluoruracil as well as lag time to deliver it in effective concentration to the colon with reduced toxicity. The lag time can be controlled by appropriate combination of polymer and excipients in coating layer. The release mechanism of 5-fluoruracil from the compression coated tablets was controlled by the rate of water uptake into the core tablet, which in turn was dependent upon the channeling agent used, the type and concentration of polymer. The hydration and swelling of these polymers results in the formation of gel which control the release of 5-fluoruracil from tablet.

Various approaches have been paused to increase the duration of oral dosage form in the stomach, including floating systems, swelling and expanding system, modified shape system, high density systems and other delayed gastric emptying devices. (Magnetic systems, Super porous -biodegradable hydrogel systems). Hydrodynamically balanced systems (HBS) -incorporated buoyant materials enable the device to float. Raft systems incorporate alginate gels - these have a carbonate component and, upon reaction with gastric acid, bubbles form in the gel, enabling floating. Swelling type of dosage form are such that after swelling, this product swell to extent that prevent their exit from the stomach through the pylorus. As, a result, the dosage form retained in the stomach for a longer period of time. These systems may be referred to as a "Plug type system," since they exhibit tendency to remain logged in the pyloric sphincters.