Insulin in oral capsule by Moscow scientists

The Moscow chemists have suggested a way to produce insulin in pills instead of injections. They have developed polymeric capsules that would protect insulin from destructive effect of digestive juices.

To create such capsules, the researchers used two polymers - positive protamin and negative dextransulphate. They formed layers in series one upon the other according to the plus towards minus principle and made a multi-layer covering around the insulin filling, which makes up to 85 percent of the entire microparticle.

Insulin covered by protective capsule is stable at pH from 1.7 to 5 units, when pH increases higher than 5 units, insulin gets released. Further pH increase up to 8 units results in accelerated protein release rate. Such behavior of particles occurs due to the fact that at pH higher than 5.5 insulin acquires negative charge and its bond with the negatively charged polymer of the first layer - dextransulphate – gets destroyed.

Such pH-dependence of protective polymeric capsules provides fundamental capability to create insulin in pills. In the stomach, where medium is extremely acid, these capsules would protect the insulin molecule and would not allow its destruction. Having gone through the stomach and having reached the small intestine and ileum, where pH reaches 6 to 8 units, capsules will start to excrete insulin intensely. In thin intestines, insulin can penetrate blood. Therefore, the capsule determines by itself where insulin should be retained in closed form and where it should be released.

And the best part is that the protective material is bio-degradable. This could also lead to delivery of several antibiotics and other medicines safely by oral means.

Link