Background <p>Bigels are biphasic composite systems that combine interlocked hydrogel and organogel networks to create a highly versatile drug delivery platform. While they effectively overcome the solubility limitations of traditional monophasic gels, their development remains largely empirical and lacks a predictive design strategy. </p> Purpose <p>This review addresses this gap by establishing a comprehensive framework that links structure, properties, and performance.</p> Methods <p>The discussion begins by detailing the core bigel components and formulation strategies, then correlates these variables with the resulting microstructural, rheological, and drug release properties.</p> Results <p>Through this analysis, the review defines the multi-compartmental mechanism of drug release, illustrating how interfacial partitioning and phase continuity govern molecular diffusion. As the review explores the translation of these properties into broad pharmaceutical applications such as dermal, mucosal, and oral delivery, it highlights a fundamental challenge inherent to bigel design: the stability-release paradox. The dense networks required for mechanical robustness and site-specific retention simultaneously create tortuous pathways that significantly retard drug availability. To resolve this conflict, the review evaluates hierarchical strategies that utilize embedded nanocarriers to effectively decouple bulk rheology from microscopic release kinetics. Finally, the review critically examines current limitations impeding industrial scale-up and predictive modeling.</p> Conclusion <p>By synthesizing these insights, this work provides a rational roadmap for engineering bigels, enabling the precise control necessary to develop advanced delivery systems with tailored therapeutic profiles.</p> Graphical Abstract <p></p>