Multifaceted applications of bile salts in pharmacy: an emphasis on nanomedicine

The human body has long provided pharmaceutical science with biomaterials of interesting applications. Bile salts (BSs) are biomaterials reminiscent of traditional surfactants with peculiar structure and self-assembled topologies. In the pharmaceutical field, BSs were employed on the basis of two different concepts. The first concept exploited BSs' metabolic and homeostatic functions in disease modulation, whereas the second one utilized BSs' potential to modify drug-delivery characteristics, which recently involved nanotechnology. This review is the first to gather major pharmaceutical applications of BSs from endogenous organotropism up to integration into nanomedicine, with a greater focus on the latter domain. Endogenous applications highlighted the role of BS in modulating hypercholesterolemia and cancer therapy in view of enterohepatic circulation. In addition, recent BS-integrated nanomedicines have been surveyed, chiefly size-tunable cholate nanoparticles, BS-lecithin mixed micelles, bilosomes, probilosomes, and surface-engineered bilosomes. A greater emphasis has been laid on nanosystems for vaccine and cancer therapy. The comparative advantages of BS-integrated nanomedicines over conventional nanocarriers have been noted. Paradoxical effects, current pitfalls, future perspectives, and opinions have also been outlined.