Delivery of Immunomodulators: Challenges and Novel Approaches

 Immunomodulators can be either synthetic in origin or naturally obtained. Natural plant-based compounds can influence the immune system by either affecting antibody secretion to control the infection or affecting the functions of immune cells, thus contributing to maintaining immune homeostasis. Phytochemicals in plants, such as polysaccharides, lactones, flavonoids, alkaloids, diterpenoids and glycosides, have been reported to possess immunomodulating properties. However, there are many challenges limiting the clinical use of natural immunomodulators. In this chapter, we have discussed in detail standardization, formulation development, route of administration and regulatory concerns of natural immunomodulators. In order to overcome these challenges and ensure that natural immunomodulators reach the target site at therapeutic concentrations, different polymer and lipid-based nanocarrier delivery systems have been developed. These nanocarriers by virtue of their size, can easily penetrate and reach the target site and deliver the drugs. Many nanocarriers like liposomes, niosomes, nanoparticles, microemulsions, phytosomes and other vesicular systems designed for natural immunomodulators are discussed in this chapter.

Keywords: Drug Delivery Challenges, Drug Delivery Systems, Immunomodulators, Immunostimulants, Immunosuppressants, Immunoadjuvants, Nanocarriers, Natural Products, Phytoconstituents.