“Enhancing Oral Drug Absorption: Overcoming Physiological and Pharmaceutical Barriers for Improved Bioavailability”

The oral route stands out as the most commonly used method for drug administration, prized for its non-invasive nature, patient compliance, and easy administration. Several elements influence the absorption of oral medications, including their solubility, permeability across mucosal membranes, and stability within the gastrointestinal (GI) environment. Research has delved into comprehending physicochemical, biochemical, metabolic, and biological obstacles that impact the bioavailability of a drug. To improve oral drug absorption, several pharmaceutical technologies and delivery methods have been studied, including cyclodextrins, micelles, nanocarriers, and lipid-based carriers. This review examines both traditional and innovative drug delivery methods, as well as the physiological and pharmacological barriers influencing medication bioavailability when taken orally. Additionally, it describes the challenges and advancements in developing formulations suitable for oral use.

Graphical abstract

This graphical abstract summarizes the key elements of oral drug delivery systems. It depicts the human digestive system, highlighting the journey of orally administered drugs. The illustration focuses on different drug molecules, including nucleic acids, proteins, peptides, and small molecular drugs, and their delivery through platforms such as liposomes, hydrogels, bacteria, algae, and microneedles. It also identifies target regions in the gastrointestinal tract—stomach, small intestine, and colon—while emphasizing the physiological barriers that affect drug absorption, such as cellular permeability, digestive enzymes, and luminal pH variations.