Introducing Freshmen To Drug Delivery

Drug delivery is an exciting multidisciplinary field in which chemical engineers play an important role. Chemical engineers apply their knowledge of mass transfer, rates and dynamic systems, and polymer materials to the design of drug delivery systems. This paper describes a simple experiment that exposes students to basic principles of drug delivery and chemical engineering. First, students are introduced to different types of dosage formulations using as examples over-the-counter-medications that are already familiar to the students. The mechanism of drug release is different for each type of formulation, and students learn how each different dosage form works. The students then perform an experiment that involves the release a drug from a lozenge formulation, which is an example of a matrix-type drug delivery system. Students study the dissolution of a lozenge into water. As the lozenge dissolves, the drug is released, along with a coloring agent, into the surrounding water. Students observe the increasing color intensity of the water, and they are able to measure the increasing drug concentration periodically using a spectrophotometer. After calculating the mass of drug released at any time t, they plot a release profile. They must calculate by material balance the mass of drug remaining in the lozenge at any time. They are also able to compare their data to a model after evaluating a single parameter in the model. Through this experiment, students are exposed to the exciting field of drug delivery, and they are introduced to some basic principles of chemical engineering. They perform a calibration to enable them to determine the concentration of drug in their samples. A spreadsheet is used to perform calculations necessary to determine the release profile, and a plot of the release profile of drug from their lozenge is created. Finally they determine the parameter necessary to apply a model to their system, and they compare their experimental release profile to that described by the model.