Scientists develop capsule shell composition for enzyme needed to treat phenylketonuria

Reviewed by Kate Anderton, B.Sc. (Editor)Jan 21 2020

IKBFU scientists developed the composition of the capsule shell for the enzyme needed in the treatment of a hereditary disease called "phenylketonuria". Phenylpyrovirogradnaya oligophrenia is a disease that results in degradation of the amino acid called phenylalanine. This amino acid presents in protein-containing food. High levels of phenylalanine can cause problems of mental development throughout life. If diet therapy is not used among children under two, then such violations lead to irreversible deviations in the development of the brain. Increasing the level of phenylalanine in the blood of an adult can reduce the level of mental abilities and reaction speed.

Director of the IKBFU's Institute of Living Systems, Olga Babich told us:

Today scientists are looking for new ways of treatment of hereditary diseases. Phenylketonuria is one of such diseases, it causes accumulation of toxic products in blood due to the metabolism malfunction in a body which it caused by insufficient amount of phenylalanine amino acid. The frequency of distribution of phenylketonuria among children in the world on average is one out of ten thousand newborns and varies from 1: 200000 to 1: 4370. In Russia, the frequency of phenylketonuria averages 1: 7000. The most common is the classic form of phenylketonuria, in which present-day diet therapy (exclusion of phenylalanine from the diet) is the only effective treatment".

According to the scientist, there are more ways of treating this disease emerging now. For example, one of the ways is enzymotherapy - enzyme treatment. But in Russia those methods are not used due to the lack of available technologies. While the most promising is the use in the treatment of an enzyme called "L-phenylalanine-ammonium lyase", both in the form of injections and capsules/pills, which breaks down phenylalanine to safe products. The therapeutic use of this enzyme is limited by its instability, especially in the acidic environment of the stomach. Therefore, the main challenge for scientists is to develop a stable capsule for the enzyme L-phenylalanine-ammonium lyase.

Olga Babich emphasized:

As part of this study, a team of scientists developed the capsule shell composition for the L-phenylalanine-ammonium lyase enzyme based on polysaccharides: agar-agar, carrageenan and hydroxypropyl methylcellulose. The effect of different storage temperatures of the enzyme in encapsulated form on its activity was also studied. We found that for all of the proposed capsule formulations, the most suitable storage temperature for the drug is 25 ° C. At capsule storage temperatures of 4 ° C and 30 ° C after 6 months, a significant decrease in enzyme activity was noted, up to 90%. The next stage of research will be devoted to studying the mechanisms of destruction of capsules with L-phenylalanine-ammonium lyase under model conditions close to the conditions of the human gastrointestinal tract, since in the future the developed capsules will be used for replacement therapy of phenylketonuria".