Researchers have developed an RNA vaccine in the form of pills with a miniature needle through which the drug is injected into the stomach wall. This method can help people who are afraid of injections, as well as deliver drugs based on RNA and DNA directly into the gastrointestinal tract.
Drug delivery capsules based on complex proteins were presented in the summer of 2021. The main component looks like an egg with a needle on the thick part. This form of it allows you to always stick into the tissues of the stomach. After the injection, the needle is retracted into the capsule and the entire device exits the body through the digestive tract.
The drug itself is in liquid form. The combination of the method of delivery and the type of drug allows it to quickly enter the bloodstream, which is vital, as is the case with insulin or adrenaline.
Why can't you just drink the medicine so that it is absorbed through the walls of the stomach? The fact is that the protein preparation can simply be digested, besides, they are poorly absorbed by themselves. Therefore, now most protein preparations, including those containing RNA and DNA, are injected.
“Nucleic acids, in particular RNA, can be extremely susceptible to degradation, especially in the digestive tract. Overcoming this problem opens up several therapeutic approaches, including possible oral vaccination,” says Giovanni Traverso, one of the study authors.
To increase the efficiency of RNA delivery, scientists have developed special delivery molecules called poly (beta-amino esters). The researchers tested their work by injecting a complex of a delivery molecule and RNA into the stomachs of mice without using needles. The RKN they delivered encodes a special protein that can be easily detected once it enters cells. The marking protein was eventually found in the stomach and liver of animals, where it probably got from other tissues and organs with blood.
The scientists then tested the final delivery system by packaging the drug into capsules. This time the test was carried out on pigs, which were injected with 3 capsules of RNA, 50 micrograms each. This is more than what is currently used in COVID-19 RNA vaccines, which contain 30 to 100 micrograms. The marking protein this time was found only in the cells of the stomach. However, this cannot be considered a complete failure.
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“There are a lot of immune cells in the gastrointestinal tract, and stimulating the gastrointestinal immune system is a known way to create an immune response,” says Alex Abramson, lead author of the study.
The researchers now want to achieve a systemic immune response and activate B and T cells using the capsules. In addition to being able to deliver many drugs and vaccines without injection, this technology could be useful for developing promising drugs for gastrointestinal diseases that are difficult to treat in other ways.
“When delivered systemically via intravenous or subcutaneous the injection is not very easy to get into the stomach,” says Abramson. “We are looking at this as a potential treatment for a variety of gastrointestinal conditions.”