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Tiny drug carriers

New methods to develop tailor-made polymers for nano-carriers

OMDB

A computer based model of the carrier molecule, bound with the medicine. Source: Brunnaci et. al. https://doi.org/10.1016/j.jconrel.2019.03.004 CC by 4.0

Nano-carriers come into play when substances are to be released locally into the body. Tiny particles made of polymers transport the medication to the target location. The substances are released at this location through diffusion, or by the polymer's degradation.

In order to be effective, they must be present in a therapeutically effective concentration. The problem with conventional polymers is that the carrier particles become unstable above a certain loading-density. This is why scientists from the HZG-Institute of Biomaterial Science in Teltow are searching for a polymer from which stable carriers for high substance concentrations can be prepared.

In this aspect, the researchers forged new paths by using computer-assisted models to pre-select polymers with which they could conduct subsequent experiments in the laboratory. This is considerably more efficient than the conventional methods, in which only experiments are involved.

Graphical abstract 2019 J. Controlled Release Brunnaci Oligodepsipeptide

The new polymer, OBMD, could deliver far higher concentrations of Dexamethasone (DXM) thatn PGLA, a standard polymer. Source: Brunnaci et. al. https://doi.org/10.1016/j.jconrel.2019.03.004 CC by 4.0

In models, as well as in experiments, researchers led by Prof Andreas Lendlein loaded two different degradable polymers - PLGA, a clinically established copolymer, and OMBD, an oligodepsipeptide still new to this application - with the commonly used anti-inflammatory medication Dexamethasone

One result of the study is that the oligodepsipeptides are much more suitable as nano-carriers than the conventional polymer. "'Depsipeptides are a very interesting substance group with a great deal of potential," says Lendlein. “The special aspect is that, due to their composition, they provide great structural diversity so that multiple physical interactions can be selected. This means that the substance adheres better to the polymer, which can therefore absorb more of the substance.”

There is still a long way to go before the substance carriers can be clinically used in a drug delivery system. The next step involves further development and optimisation of the synthesis in accordance with regulatory requirements for drug development.

More in Journal of Controlled Release

This article appeared in In2Science 8