Bilayer Gastroretentive Modified-Release Tablets: A Quality-by-Design Approach to Achieving Precise Drug Release and Prolonged Gastric Retention

Bilayer gastroretentive modified-release (GR-MR) tablets offer a robust strategy to overcome rapid gastric emptying, ensuring precise release kinetics and enhanced bioavailability for drugs with site-specific absorption. This white paper applies a Quality-by-Design (QbD) framework to address the complexities of these systems, integrating an immediate-release (IR) layer with a gastroretentive extended-release (GR-ER) layer. 

Key focus areas include: 

• QbD Implementation: Systematic translation of the Quality Target Product Profile (QTPP) into Critical Quality Attributes (CQAs), focusing on bilayer integrity, mechanical strength, and expansion kinetics. 

• Technical Methodology: Utilization of compaction simulation for interlayer bonding, PBPK modeling for dose design, and the M3 (Material + Molecule + Medicine) philosophy for precise CMAs and CPPs selection. 

• Performance & Stability: Advanced in-vitro dissolution testing and mitigation strategies for oxidative, acid-catalyzed, and metal-catalyzed degradation. 

• By leveraging deep material science and systematic process control, this platform enables reliable gastric retention and optimal therapeutic performance for challenging molecules.