To control the sugar level in blood, diabetics have to take injections regularly, up to several times a day, which makes their life more difficult. The lack of timely injection may result in a fatal outcome. Chemists have developed polymeric capsules to protect insulin from destructive effect of digestive juices. The pills would significantly simplify their life. However, the fact that insulin gets quickly destroyed when it appears in acid medium of the stomach does not exclude, but significantly creates problems for insulin in the pill form. Researchers of the Chemical Faculty, Lomonosov Moscow State University have found the way to protect insulin from the destructive effects of the digestive juices and to preserve the ability to perform its function.

To introduce insulin in the organism, the Russian chemists have used multi-layer polymeric capsules. These polymeric capsules are stable and remain intact in acid medium and they gradually excrete insulin in a neutral medium. The two polymers used are: positive protamin and negative dextransulphate. They form layers in series one upon the other according to the plus towards minus principle and make a multi-layer covering around the insulin filling, which makes up to 85% of the entire microparticle.
Insulin covered by protective capsule is stable in acidic medium of pH from 1.7 to 5 units. When pH increases to a level above 5units, insulin gets released. Further pH increase of 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 units of 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.

The polymers used to create capsules belong to natural biodegradable polymers. After utilization they get easily destroyed by enzymes and removed from the organism without causing any harm to health.