Nearly a century after the crucial discovery
of insulin, Indian scientists have developed a long-sought insulin pill that
could spare millions of diabetics around the world the pain of daily jabs.
In experiments with rats, the 'pill' lowered
blood glucose levels almost as much as injected insulin. In fact, the effects
of the 'pill' lasted longer than that of injected insulin, according to the
study published in the American Chemical Society journal Biomacromolecules.
For years, researchers have sought a way to
transform delivery of insulin therapy from a jab to a pill, but it has been a
challenge. The body's digestive enzymes that are so good at breaking down food
also break down insulin before it can get to work. In addition, insulin does not get easily
absorbed through the gut into the bloodstream.
To overcome these hurdles, researchers from
the National Institute of Pharmaceutical
Education and Research (NIPER) in Punjab, combined two approaches to shield
insulin from the digestive enzymes and then get it into the blood.
The team, which included researchers Ashish
Kumar Agrawal, Harshad Harde, Kaushik Thanki and Sanyog Jain, packaged insulin
in tiny sacs made of lipids, or fats, called liposomes, which are already used
in some treatments. Then, they wrapped the liposomes in layers of protective molecules
called polyelectrolytes. To help these "layersomes" get absorbed into
the bloodstream, they attached folic acid, a kind of vitamin B that has been
shown to help transport liposomes across the intestinal wall into the blood.
In rats, the delivery system lowered blood
glucose levels almost as much as injected insulin, though the effects of the
layersomes lasted longer than that of injected insulin. An estimated 347 million people globally are
living with diabetes, a condition where the body fails to utilise the ingested
glucose properly. This could be due to lack of the hormone insulin or because
the insulin that is available is not working effectively. Diabetics must test
their blood sugar several times a day, and need insulin jabs for the rest of
their lives in order to maintain adequate levels of the hormone.
