Functional polymers for drug delivery – prospects and challenges
The fields of polymer and pharmaceutical chemistry have become of critical importance for clinical drug delivery, allowing for a significant improvement in the way that drugs are administered.
In particular, polymer-based nanomedicines show immense promise for achieving the ‘holy grail’ of pharmaceutical science: site-specific delivery of active molecules with no off-target effects. This short review highlights some recent notable examples and strategies towards fulfilling this aim, focussing on drug delivery systems constructed through polymerisation techniques such as Ring Opening Polymerisations (ROP) and controlled radical polymerisations. We further consider inherently therapeutic polymers, supramolecular assemblies and nanoparticle formulation techniques, with a final outlook towards the eventual commercialisation of nanoparticle therapeutics.
Polymers have become indispensable in the field of drug delivery, primarily as excipients in extended drug release formulations, and increasingly as carriers for therapeutic agents which otherwise have poor pharmacokinetic properties (1). For example, many potential drugs for infectious diseases and for cancers are poorly water-soluble, limiting their availability at the intended site, or are prone to degradation by proteins and enzymes when introduced into the body by ingestion or injection. Therefore, a significant field of research has emerged focussing on polymers which might improve the transport of drugs to disease sites such that the therapeutic is delivered to the target sites at the right time, and in the correct dose (2).
Polymeric-based nanoparticles are now showing great promise for achieving the ‘holy grail’ of drug delivery: site-specific delivery of active molecules with no off-target effects. While there are only a few examples of nanoparticle drug delivery systems in human use, the most notable being Doxil®, (adopted for cancer therapy since 1996), there are many emerging polym ...