Advancements in Oral Drug Delivery of Insulin: A Review

Insulin administered subcutaneously to treat diabetes mellitus may cause local infection, pain, discomfort, and non-compliance for the patient. Since oral delivery is the most widely used method of administration, when compared to other invasive drug delivery systems, our goal was to focus on the difficulties associated with oral insulin delivery, as well as the many carriers that are utilized to do so. We also aimed to present pertinent information regarding the oral insulin formulations that have been clinically tested.

We scientifically searched the electronic database of PubMed from inception until September 28, 2023, using MeSH keywords. We additionally searched for formulation studies related to the oral delivery of insulin. We retrieved all available studies of different formulations in the oral administration of insulin. Subsequently, we reviewed the results narratively.

Eight formulation studies were taken for review. Better oral insulin administration was demonstrated using several formulations including hydrogel, liposomes, insulin conjugates, micro-/nanoparticles, pills, and tablets.

We conclude that oral administration of chitosan-based insulin shows significant bioavailability and therapeutic activity compared to other bio-adhesive delivery systems.