Drug Delivery


NANOMEDICINES exploring the past, present and future


Nanoparticles, and liposomes in particular, are growing in popularity as drug delivery vehicles for anti-cancer agents and inflammatory disease therapies, as well as forming the basis of a new class of vaccines. They offer a number of advantages in terms of stability, efficacy and off-target effects, but traditional manufacturing methods are labour-intensive, hard to reproduce and difficult to scale up. This has contributed to a widely-held perception in the pharmaceutical industry that nanomedicines are far from clinically practical. A new generation of microfluidic systems is helping to overcome these issues, allowing the rapid development and seamless scale-up of novel nanoparticles. This technology is transforming the development and manufacture of a range of nanoparticle formulations from a hit-and-miss affair into a standardised process, accelerating novel nanomedicines from the bench to the clinic.


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anoparticles comprised of polymers or lipids can be used to encapsulate biologi- cal or small molecule active pharmaceuti- cal ingredients (APIs) for drug delivery. This approach offers a number of advantages over tra- ditional drug formulations, principally that the API is protected from harsh extracellular environmen- tal conditions in vivo, allowing delivery of the intact API into the target tissues, cells and sub-cel- lular compartments, while shielding it from chem- ical or enzymatic degradation. Correspondingly, nanoparticles can be used to prevent highly toxic APIs – such as the cytotoxic agents used in cancer therapies – from causing off-target unwanted side- effects.


Packaging the API within nanoparticles not only shields the drug from the body, or vice versa, it also effectively decouples the relationship between drug


Drug Discovery World Fall 2017


structure and biological targeting. By ‘hiding’ the drug in the nanoparticle, its properties are masked from biological processes which dictate its in vivo localisation. Varying the physical properties or chemical structure of the nanoparticles, therefore, allows more effective targeting without compro- mising API structure or function. A number of potential in vivo targeting strategies have been sug- gested, including coupling the particles to antibod- ies or other biologically-derived recognition ele- ments, but the majority of nanomedicines currently in development rely on adjusting the physicochem- ical properties of the particles themselves. Liposomes – spheres composed of phospholipid bilayers which are used to encapsulate drugs – are the forerunners in the nanomedicine arena, with the first FDA-approved example, Doxil®, first appearing in 1995. A major benefit of liposomes as


By Professor Yvonne Perrie and


Dr Euan Ramsay


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