Lipid-Based Drug Delivery Systems (LBDDS) for Bioavailability Enhancement: Formulation Strategies and Recent Advances

Poor aqueous solubility remains a critical challenge in the oral delivery of a large proportion of new and existing drug molecules, often resulting in low and variable bioavailability. Lipid-based drug delivery systems (LBDDS) have emerged as a robust formulation approach to address these limitations by maintaining drugs in a solubilized state and exploiting physiological lipid digestion and absorption pathways. This review provides a focused overview of the principles and classification of LBDDS, with particular emphasis on self-emulsifying systems and lipid nanoparticle-based formulations. The key mechanisms governing oral bioavailability enhancement, including solubilization, lymphatic transport, and modulation of intestinal permeability and metabolism, are critically discussed. Furthermore, formulation strategies, characterization approaches, and quality-by-design-based considerations influencing in vivo performance and regulatory acceptance are summarized. Commercially successful lipid-based products are highlighted to demonstrate clinical relevance. Finally, current challenges, recent technological advances, and future perspectives in LBDDS development are outlined. Overall, lipid-based delivery systems represent a versatile and translational platform for improving the oral bioavailability of poorly water-soluble drugs.