Advances in Oral Drug Delivery Systems: Challenges and Opportunities

Abstract

The oral route is the most preferred route for systemic and local drug delivery. However, the oral drug delivery system faces the harsh physiological and physicochemical environment of the gastrointestinal tract, which limits the bioavailability and targeted design of oral drug delivery system. Innovative pharmaceutical approaches including nanoparticulate formulations, biomimetic drug formulations, and microfabricated devices have been explored to optimize drug targeting and bioavailability. In this review, the anatomical factors, biochemical factors, and physiology factors that influence delivering drug via oral route are discussed and recent advance in conventional and novel oral drug delivery approaches for improving drug bioavailability and targeting ability are highlighted. We also address the challenges and opportunities of oral drug delivery systems in future.

Keywords: gastrointestinal barriers; novel drug delivery system; oral drug delivery system; oral nanomedicine; oral target delivery.

Figure 1

Local targeting drug delivery systems to GIT after oral administration.

Figure 2

Targeting delivery systems to non-gastrointestinal diseases after oral administration.

Figure 3

Schematic diagram of YC-mediated nanoparticles to inflammation-associated diseases [118]. Reproduced from ref. [118] with permission from the American Chemical Society, copyright 2017.

Figure 4

Schematic diagram of a CDDP nanoprecursor for targeted tumor treatment [120]. Reproduced from ref. [120] with permission from the author.

Figure 5

Schematic illustration of the fabrication and transepithelial transport mechanism of DOX/SOR/Spore-DA [121]. Reproduced from ref. [121] with permission from the John Wiley and Sons, copyright 2018.

Figure 6

Schematic diagram of LAM-mediated oral targeting of nanoparticles to multiple sites of obesity related diseases [122]. Reproduced from ref. [122] with permission from the author.

Figure 7

Schematic diagram of the noninvasive gut-to-brain oral drug delivery system [124]. Reproduced from ref. [124] with permission from John Wiley and Sons, copyright 2021.