Self-Assembled Polymer Complexes Have Potential Drug Delivery Role

Drug developers have demonstrated the possibility of using mixtures of inert polymers with different configurations and tacticities that self-assemble without outside stimulus (stereocomplexation) to construct active particles that have potential use for controlled release and delivery applications.

Investigators at the University of Warwick (United Kingdom) prepared stereocomplex micelles from a mixture of poly(L-lactide)-b-poly(acrylic acid) and poly(D-lactide)-b-poly(acrylic acid) diblock copolymers in water via crystallization-driven self-assembly. They reported in the December 17, 2014, online edition of the journal Nature Communications that during the formation of these stereocomplex micelles, an unexpected morphological transition resulted in the formation of dense crystalline spherical micelles rather than cylinders.

The investigators theorized that each of the component polymers could carry an inactive drug precursor. When placed in close proximity, the component polymers would undergo stereocomplexation to form a new molecule containing the now active drug. The new particles would be taken up by cells where they would break down and release their drug cargo.

"We conceive that in the blood stream the particles would not be able to interact sufficiently to lead to release, only when they are taken into cells would the release be able to happen", said senior author Dr. Andrew Dove, professor of chemistry at the University of Warwick. "In this way, the drug can be targeted to only release where we want it to and therefore be more effective and reduce side effects. This research raises new possibilities in how we can administer medical treatments. We are planning to study this as a new treatment for cancer but the principle could potentially be applied to a wide range of diseases."

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