Drug Delivery

In the last several decades a wide variety of new and highly potent drugs have been discovered. However, it remains a formidable challenge to find appropriate formulations for the administration of these drugs. Besides poor stability, these drugs tend to have a short half-lifes in plasma and tissue. These factors dramatically limit the availability of the drug at the intended site of action.

From this problem, a central issue of pharmaceutical technology arises: how can we “pack” these drugs into an appropriate transport system or dosage forms? In answering this question, approaches go back to Paul Ehrlich, who hypothesized that a “magic bullet” is necessary for the selective, targeted application of drugs.

At the Department of Pharmaceutical Technology, we attempt to develop drug delivery systems that allow for the controlled release of proteins and peptides. One possibility involves incorporating proteins in the solid state into suitable carrier systems. In this form, proteins can be directly administered (e.g. pulmonarily) or applied in parenteral depot formulations.

Figure: (A) Confocal picture of CHO cells transfected with fluorescently labeled siRNA. (B) Distributions of quantum dots in biodegradable PEG-b-PLA microparticles.

Nanoparticles present another possibility for targeted drug delivery and imaging. The intracellular fate of macromolecular drugs depends on the pathway of their cellular uptake. Fluorescence-based detection methods are an important tool in detecting these pathways, as the high sensitivity of highly resolving microscopes allows for direct observation of the uptake of particles into cells. Quantum dots and fluorescent semi-conductor nanocrystals possess significant advantages compared to conventional organic fluorescent dyes, as they reveal how drugs enter cells. This knowledge can be used to develop non-viral gene delivery systems.