Insulin pills could spell end of painful jabs for diabetes

Scientists have developed a new way of administering insulin orally that could prove to be a painless alternative to millions of diabetics worldwide who have to get injections to manage their blood-sugar levels.

The new oral method uses tiny vesicles that can deliver insulin where it needs to go without a shot, researchers said.

"We have developed a new technology called a Cholestosome. A Cholestosome is a neutral, lipid-based particle that is capable of doing some very interesting things," said Mary McCourt from Niagara University in the US.

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 are needed.

Using the patented Cholestosomes, McCourt, Lawrence Mielnicki and undergraduate student Jamie Catalano, all from Niagara, have successfully encapsulated insulin.

The novel vesicles are made of naturally occurring lipid molecules, which are normal building blocks of fats. But the researchers say 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're just using simple lipid esters to make vesicles with the drug molecules inside," said Mielnicki.

Computer modelling 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 recognises 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.

The team has delivered multiple molecules with these vesicles into cells in the lab.

To pack the most insulin into the Cholestosomes, the researchers determined the optimal pH and ionic strength of the drug-containing solution.

They then moved the most promising candidates on to animal testing. 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.