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Less drug residues in the environment


Degradation of diclofenac: less drug residues in the environment

In the past few years, studies have repeatedly shown an often extremely dangerously high proportion of pharmaceutical residues in the environment. The widespread pain reliever diclofenac in particular is a major burden. But researchers have now been able to show for the first time how the drug can be broken down in the soil and what hinders its breakdown.

Environmental pollution

Scientific studies repeatedly show how drug residues pollute our environment. According to experts, although new processes are always being worked on, the residues can hardly be removed. Among other things, consumers are therefore repeatedly asked not to dispose of medication residues in the drain. But human excretions also release pharmaceutical components into the environment, including those of the widely used pain reliever diclofenac. A research team led by Prof. Bernhard Hauer from the Institute of Biochemistry and Technical Biochemistry at the University of Stuttgart has now been able to show for the first time how this drug can be broken down in the soil and what hinders its degradation.

Widely used pain reliever

Whether for bruises or rheumatism: Diclofenac is prescribed as an anti-inflammatory and analgesic drug in Germany alone more than 14 million times a year, according to a statement from the University of Stuttgart.

According to the information, more than 90 tons of the active ingredient are marketed in this way. But the popular remedy is both a curse and a blessing, because diclofenac is only absorbed to a certain extent by the body.

Around 60 percent of the active ingredient is discharged into the wastewater through natural excretion, and despite modern wastewater treatment technology it has not been possible to remove these residues to date.

In the end, the residues collect in nature, where the substance can already be found in different habitats and also becomes part of the food chain.

So far, the only option left was to track the fate of the drug in the environment. Techniques for breaking down diclofenac molecules and eliminating them from our habitat did not exist.

Interaction of certain microorganisms

In laboratory experiments, scientists at the University of Stuttgart have now succeeded for the first time in demonstrating the degradation of diclofenac in soil samples. The decisive factor for the success of this degradation process is the interaction of certain microorganisms.

The decomposition of the compound is initiated by a so-called carboxylation, an unusual reaction in nature. It was only through highly sensitive analysis that the metabolic product of the microbes was discovered.

The team of researchers also found out what hinders the breakdown of diclofenac: this particularly includes carbonates or phosphates, which is particularly problematic since they can also be found in wastewater in considerable quantities.

The results of the scientists were published in the "Environmental Technology & Innovation" magazine.

The Stuttgart researchers now hope that their findings will help to rid the environment of one of the numerous anthropogenic substances.

In further work they want to try to understand the new reaction biochemically and to investigate whether it can also be applied to other drugs. (ad)

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