Ritesh Kumar Tiwari

This chapter addresses the potential of nanotechnology to overcome one of the main barriers in the treatment of major depressive disorder (MDD), the blood–brain barrier (BBB), and the increased potential for drug delivery to the brain. Routine antidepressants have only been partially effective in treating depression because they do not easily cross the BBB, take too long to have an effect on patients, lack high bioavailability, and cause systemic side effects. In order to overcome these drawbacks, new nanotechnology-based drug delivery systems such as, liposomes, polymeric nanoparticles, dendrimers, nanoemulsions, and inorganic nanoparticles have been introduced. These nanocarriers increase the effectiveness of drug stability, controlled drug release, drug targeting, and brain bioavailability, while decreasing drug toxicity and off-target effects. This chapter also discusses the BBB structure, BBB drug delivery challenges, mechanisms of nanoparticle transport, and advanced targeting of the BBB through receptor-mediated delivery and PEGylation. Various recent advancements, including smart nanoparticles, artificial intelligence (AI)-enabled delivery systems, gene-based therapies, and personalized nanomedicine, are also discussed. Overall, nanotechnology offers a paradigm shift in how to overcome BBB barriers and enhance the safety, efficacy, and precision of antidepressant treatment in future clinical use.

Background/Objectives: Traditionally classified as nutrients or micronutrients, vitamins can now be viewed as multi-functional excipients that have considerable potential within the context of pharmaceutical formulation science. Due to their physicochemical characteristics, antioxidant nature, and stabilizing action, vitamins are able to serve functions that go beyond their nutritional applications. These include but are not limited to solubility, increased permeation, controlled release, as well as synergistic stabilization and enhancement of the active ingredient(s). Results: The current work presents the synthesis of information available to date regarding the classification, mechanisms, and excipient properties of vitamins and their role in novel drug delivery systems development. In addition to the conventional classification into water-soluble and fat-soluble, some other classification criteria are used based on the chemical nature of vitamins. Water-soluble vitamins are mainly used to facilitate oxidation and pH adjustments whereas fat-soluble vitamins are mostly employed in lipid-based systems due to solubilizing and antioxidative effects. Conclusion: Vitamin-based mechanisms such as the surfactant effect of TPGS (vitamin E), oxidation and reduction reactions in vitamin C, or hydrotropy in niacinamide illustrate active involvement of vitamins in enhancing bioavailability and improving the formulation. Novel areas of application range from vitamin-functionalized nanocarriers to receptor-targeted ligands and incorporation into 3D-printed drug delivery platforms.