Authors: Barrett Lindsey, Kevin Sneed, Yashwant Pathak.
Patients tend to prefer the oral administration of medication, as it is typically the easiest and most convenient [1]. It is typically the most advantageous route for physicians due to its many benefits including non-invasiveness, patient compliance, and convenience of drug administration [2]. Despite this, the oral administration of biologics has yet to be proven effective due to the physiological barriers of the gastrointestinal tract. The gastrointestinal tract presents multiple barriers that limit the systemic absorption of complex macromolecules after ingestion. Various factors govern oral drug absorption including drug solubility, mucosal permeability, and stability in the gastrointestinal tract environment. Biologics are highly sensitive to the harsh environment of the GI tract. In addition to this issue, the relatively large molecular size of biologics causes the permeability across the intestinal mucosa to become extremely poor.
Research in the field of drug discovery and design has proliferated the ways in which we administer medications in a clinical setting and the growth of biologics in recent decades has further accelerated research activity. Different pharmaceutical technologies and drug delivery systems including nano carriers, micelles, cyclodextrins, and lipid-based carriers have been explored to enhance oral drug absorption. This article will serve to address the main physiological barriers to oral delivery of biologics and discuss different research strategies to improve the effectiveness of oral delivery. Additionally, this discussion will highlight the advantages and limitations of oral drug delivery systems as well as the overall viability and potential of this future clinical field.
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