ABSTRACT
The oral bioavailability of the drug is also influenced by some other factors like chemical degradation of the drug in gastrointestinal (GI) fluid, gastric emptying rate, and intestinal motility. The selection of a drug delivery route is primarily focused on patient acceptability, physicochemical properties of the drug, and target area. The stability of nanoparticles over a wide range of pH variation in the GI tract (GIT) is most important. Nanoparticles reach the stomach after administration through the mouth. The susceptibility of nanoparticles to different digestive enzymes present in the GIT poses a significant hurdle to achieve a desired therapeutic efficacy after oral administration. The transcellular pathway involves the transport of drug molecules across the lipophilic membrane of the epithelial cells via passive diffusion, active transport or endocytosis. The transport of nanoparticles across enterocytes is an energy-dependent process, mainly occurred by macropinocytosis, clathrin, or caveolae-mediated endocytosis and clathrin and caveolae-independent endocytosis.
