Abstract

The pharmaceutical industry has witnessed a huge revolution in the past few decades due to the discovery of various novel drugs for the treatment of several lifethreatening ailments. However, there is a continued interest in exploring nature for inventing therapeutically active novel compounds. Among the various natural resources, plants constitute an invaluable source of bioactive molecules. Numerous studies have illustrated the exceptional therapeutic efficacy of phytochemicals against various diseases. Some of the well-known drugs, such as paclitaxel, vincristine, vinblastine, etc., which can potentially be used in cancer therapy, were first isolated from plants. Later, several other drug-active molecules, which have demonstrated promising therapeutic effects, were discovered. Despite their outstanding antimicrobial, antidiabetic, and anticancer effects in vitro, most of these molecules fail to achieve a similar effect in vivo, mainly due to their poor aqueous solubility and bioavailability. The advent of nanotechnology and the application of nano-drug delivery carriers have significantly revolutionized the biomedical industry. Numerous studies indicate the successful utilization of nanoparticles for theragnostic applications. Nanoparticles having a size of approximately 507250 nm can efficiently interact with cellular structures, eliciting desirable therapeutic effects. Apart from improving the aqueous dispersibility and stability of drugs, nanoparticles enable cell-specific as well as receptor-specific drug targeting, thereby reducing the off-target effects. Moreover, the stealthy nature of surface-modified nanoparticles, in combination with the controlled release of encapsulated drugs, enables prolonged therapeutic activity in vivo. This chapter presents an updated summary of the applications and challenges of various nano-drug carrier systems for the delivery of natural bioactive principles.