A Comprehensive review on bilayer tablet

Bilayer tablet technology is an innovative drug delivery system developed to achieve different release patterns within a single dosage form. These tablets generally consist of two layers, namely an immediate release layer and a sustained release layer, which help provide a rapid onset of action along with prolonged therapeutic effect. The present review focuses on the formulation, preparation, evaluation, advantages, limitations, and applications of bilayer tablet technology. Bilayer tablets are widely used to improve patient compliance, reduce dosing frequency, separate incompatible drugs, and maintain consistent plasma drug concentration for an extended period. The review discusses various techniques involved in bilayer tablet formulation such as OROS push-pull technology, L-OROS™, ENSOTROL™, DUROS®, and DUREDAS™ technologies. Different types of bilayer tablet presses and the manufacturing process, including compression and consolidation, are also described. Important evaluation parameters such as hardness, friability, weight variation, dissolution testing, thickness, and stability studies are highlighted to ensure the quality and performance of bilayer tablets. Bilayer tablets offer several advantages, including improved therapeutic efficacy, better patient convenience, enhanced stability, and controlled drug release profiles. However, challenges such as layer separation, cross-contamination, poor compressibility, and manufacturing complexity may arise during formulation development. Proper selection of excipients, polymers, and processing parameters is essential to overcome these limitations. Overall, bilayer tablet technology represents a promising and advanced approach in oral drug delivery systems by combining immediate and sustained drug release within a single formulation, thereby improving treatment effectiveness and patient adherence.