Tablet "Janus"

Researchers from the Massachusetts Institute of Technology and Brigham and Women's Hospital in Boston, working under the guidance of Dr. Giovanni Traverso and Professor Robert Langer, have developed a new type of pill that, after ingestion, attaches to the inner wall of the intestine and slowly releases its contents.

The developers claim that such tablets for prolonged release of the active substance will reduce the dosages of many drugs. For example, antibiotics, traditionally used 2-3 times a day, can be taken 1 time a day, which will make it easier for patients to comply with the treatment protocol.

Over the past few decades, the staff of Professor Langer's laboratory have developed many types of materials suitable for implantation into the body or capable of attaching to the skin for prolonged release of drugs. To ensure a similar prolonged release in the digestive tract, the researchers used a material with mucoadhesive properties, that is, the ability to attach to the mucous membrane of organs.

Previously, experts have already made attempts to use such materials to release drugs in the digestive tract, but this turned out to be a difficult task due to the fact that liquid and fragments of food stuck to the tablet, tearing it from the intestinal wall before it had time to release its contents.

To overcome this problem, the authors decided to create a two-sided device, nicknamed "Janus" in honor of the two-faced Roman god. One side of it adheres to the surface of the mucous membrane, while the second has omniphobic properties, that is, it repels everything that comes into contact with it.

To create a flour-adhesive surface, they used a commercially available polymer Carbopol (Carbopol), often used in industry as a stabilizer or thickener. The omniphobic side consists of cellulose acetate, structured in such a way that its surface resembles the surface of a lotus leaf, covered with micro- and nano-steps providing exceptional hydrophobicity. In addition, the surface was fluoridated and coated with a lubricant, which gave it the ability to repel almost any material.

With the help of a tablet press, the researchers formed double-sided pills from polymers, the shape and size of which can vary depending on the task. The active ingredients can be integrated into a cellulose acetate layer or placed between two main layers.

Three variants of tablets were tested on swine intestinal tissue samples: a double–sided adhesive tablet, a double-sided omniphobic tablet and a "Janus" tablet, one side of which is mucoadhesive, and the second is omniphobic.

To reproduce the extreme conditions of the digestive tract, the researchers organized a continuous movement of a fluid flow containing pieces of bread and rice over a tissue sample, after which they introduced a test tablet into it. It took less than a second for the double-sided omniphobic tablet to move over the tissue sample, and the double-sided mucoadhesive tablet stuck to the tissue, but was torn off and carried away by the flow after 7 seconds. At the same time, the experimental version of "Janus" lasted on the surface of the tissue for the entire experiment lasting 10 minutes.

Experts believe that the new approach will allow delivering more significant doses of drugs through the digestive tract than was previously possible. Moreover, the possibility of creating tablets that selectively attach to specific regions of the digestive tract will allow increasing local or systemic levels of concentration of certain drugs.

Currently, the developers are planning to conduct additional experiments on animals in order to find out the duration of the period during which the experimental tablet will be able to linger in the digestive tract, as well as the rate of release of drugs and the possibility of selective attachment of the tablet to various parts of the digestive tract.

Another idea that they plan to work out in the future is to create two-sided omniphobic tablets for patients who have difficulty swallowing, as well as to prevent the tablet from sticking to the wall of the esophagus, which often leads to the development of irritation and inflammation of its mucous membrane.

Article by Young-Ah Lucy Lee et al. A Janus Mucoadhesive and Omniphobic Device for Gastrointestinal Retention is published in the journal Advanced Healthcare Materials.

Evgeniya Ryabtseva
Portal "Eternal youth" http://vechnayamolodost.ru based on the materials of the Massachusetts Institute of Technology: Engineers develop a pill for long-term drug release.

07.04.2016