ABSTRACT:
The target in tablet dosage form design is intended to enable drug delivery in a form that maximizes the therapeutic benefit without making the system prohibitively expensive. One way of enhancing efficacy of drugs in tablet dosage forms is formulating them as modified release drug delivery systems, with a view to overcome several shortcomings such as physicochemical limitations of the drug itself or its poor pharmacokinetic profile. Conventional modified release matrix tablets generally release the drug at a slow first order rate. Greater flexibility in formulation design is possible with the advent of multilayer tablet technology. Immediate release multilayer tablet can overcome the problems of drugs and/or excipients that are incompatible, modified release multilayer tablet offer the versatility of designing sustained release formulations having zero-order drug release or release profile tailored to achieve a specific objective such as pulsed release, quick-slow release, biphasic release, etc., while site-specific multilayered tablets provide the flexibility of designing gastroresistant, gastroretentive, colon-specific or mucoadhesive formulations. While multilayered tablets gives a formulator opportunity to design a dosage form having desired product performance characteristics, manufacture of such a formulation and its scale-up are challenges and a thorough understanding of tablet press design, process parameters and formulation components is important.