Nanoparticles: Facilitating Targeted Drug Delivery in Cancer Therapy

Engineering nanoparticles with optimal properties for use in cancer therapies.
Mar 02, 2013
Volume 37, Issue 3

PharmTech spoke to Robert Langer, professor at the Massachusetts Institute of Technology and founder of BIND Biosciences; Stephen Zale, vice-president of development at BIND Biosciences; and Yanli Zhao, assistant professor and national research foundation fellow at Nanyang Technological University, Singapore, about engineering nanoparticles with optimal properties for use in cancer therapies.

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Nanoparticles have significantly changed the scientific landscape of disease treatment, prevention, and diagnosis, generating a new wave of nanoscale drug-delivery strategies. From solubility/bioavailability enhancement (1, 2) and targeted drug delivery (3, 4) to controlled/sustained release (5, 6) and protection of labile molecules (e.g., proteins, peptides, and DNA) from enzymatic degradation (7, 8), these structures can be manufactured, controlled, and manipulated to take on novel properties and functions that have opened new doors in the biomedical arena.

While nanoparticles may vary in size ranging from 10 nm to 1000 nm, nanomedicines are typically less than 200 nm (9). Nanoparticles made from natural or synthetic polymers have gained popularity because of their stability and ease of surface modification. They can be engineered to achieve controlled drug release as well as specific localization at disease sites by modification of the polymer characteristics and surface chemistry. For example, it has been well established that nanoparticles accumulate preferentially at tumor and inflammatory sites due to the enhanced permeability and retention effect (EPR) of the vasculature (9–11). At the target site, the biodegrable polymeric nanoparticles can act as a local drug depot that provides continuous release of the encapsulated therapeutic agent.

These advantages offered by nano-particles for targeted drug delivery are a result of their small size and the use of biodegradable materials. The small size enables the nanoparticles to overcome biological barriers (e.g., gastro-intestinal epithelium, tumor vasculatures, and endothelium of inflammatory sites) and achieve cellular uptake while the use of biodegradable materials allows for sustained drug release at the target site (9–11).

Advances in the development of nanoparticles have seen these systems being translated into clinically useful medicines, particularly in the treatment of cancer. Examples of nanoparticle-based medicines approved by FDA and EMA as cancer therapies include Doxil and Myocet (liposomal formulations of doxorubicin), DepoCyt (liposomal cytarabine), Dauno-Xome (liposomal daunorubicin), Abraxane (an albumin-bound formulation of paclitaxel), and Genexol-PM (a polymeric-micelle formulation of paclitaxel).

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