US scientists have developed an oral method of administering insulin that can be a less painful alternative to millions of people worldwide with diabetes who have to inject themselves with the drug to manage their blood-sugar levels. The team has successfully encapsulated insulin using Cholestosomes – a neutral, lipid-based particle – that can be administered orally with tiny vesicles that can deliver insulin where it needs to go without injecting.
The biggest obstacle to delivering insulin orally is ushering it through the stomach intact. Proteins such as insulin are no match for the harsh, highly acidic environment of the stomach. They degrade before they get a chance to move into the intestines and then the bloodstream where they’re needed, the study said. However, the new vesicles that are made of naturally occurring lipid molecules are normal building blocks of fats, the researchers said, adding that they are unlike other lipid-based drug carriers, called liposomes.
“Most liposomes need to be packaged in a polymer coating for protection. Here, we are just using simple lipid esters to make vesicles with the drug molecules inside,” said lead researcher Mary McCourt, Professor at Niagara University in New York, US. Computer modeling showed that once the lipids are assembled into spheres, they form neutral particles resistant to attack from stomach acids. Drugs can be loaded inside, and the tiny packages can pass through the stomach without degrading.
When cholestosomes reach the intestines, the body recognizes them as something to be absorbed. The vesicles pass through the intestines, into the bloodstream, and then cells take them in and break them apart, releasing insulin. Studies with rats showed that certain formulations of cholestosomes loaded with insulin have high bioavailability, which means the vesicles travel into the bloodstream where the insulin needs to be, the researchers concluded. The results were presented at the 252nd National Meeting and Exposition of the American Chemical Society (ACS), in Philadelphia, recently.