Professor of Chemical Engineering, Professor of Health Sciences
Program Focus
Our main research goal is the development of drug-containing nanoparticles (typically 50-500 nm in diameter) with well-defined size distributions, drug compositions, and drug release kinetics. The formation of submicron drug particles with well-defined particle size distributions and biocompatibility is important for drug delivery applications. The size distribution affects the kinetics of drug release and, along with biocompatibility, can be controlled by complexation with polymers with tailored structures and molecular weights. Both insoluble, hydrophobic drugs as well as charged, water-soluble drugs are currently under study. The particles are typically stabilized with polymers – synthesized by collaborators at Virginia Tech – that can form attached or extended brushes which provide biocompatibility. Particle systems currently under investigation include:
1. Polymer nanoparticles complexed with water-insoluble and also water-soluble drugs along with superparamagnetic magnetite nanoparticles for enhanced magnetic resonance imaging – These particles have the potential for use as theranostic systems that combine drug delivery and an imaging functionality.
2. Polysaccharide-based nanoparticles that can incorporate water-insoluble, hydrophobic drugs for oral delivery – Our objective is to form nanoparticles of drugs combined with polymers designed to improve delivery of insoluble drugs and make it possible for drugs to be delivered orally that currently cannot be delivered at all or require intravenous (IV) delivery. Oral administration of drugs is by far the most preferred mode of delivery for delivery of drugs for illnesses such as hypertension and high cholesterol. However, many drugs, such as those used to treat diseases such as tuberculosis and cancer, cannot currently be delivered by oral means and thus require intravenous (IV) delivery. Other drugs, such as those used to treat HIV, are delivery orally but with poor efficiency. In many cases, these drugs have poor water solubility which partly accounts for the poor oral delivery and also greatly complicates IV delivery. We are studying polysaccharides which are very promising for oral drug delivery due to their affinity for complexing with a variety of drugs which can suppress crystallization of the drugs, their relatively high glass transition temperatures, and their biocompatibility. We employ a high-speed precipitation process that can produce drug-polymer particles with tunable sizes in the range of 50-200 nanometers (nm) needed for optimal drug solubility. Due to the high area/volume of these particles, significant increases in mass transfer rates are possible. Reducing particle diameter from 1 micron to 50 nm increases the specific area and can increase the drug mass transfer rate by 400-fold.