Characterization of mass application techniques for a quartz crystal microbalance (QCM) drug dissolution test method

A novel dissolution testing methodology has been developed using a commercial quartz crystal microbalance (QCM) system to measure dissolution rates of drugs. Our technique system is more advantageous than current pharmaceutical methods, which are resource, sample, and time intensive. Current methods measure dissolution rate by taking samples of the solution at given time intervals and determining the concentration until the drug has fully dissolved. However, the QCM method is capable of measuring mass changes directly and rapidly. Additionally, the sample required is orders of magnitude less than traditional methods. In this work, we aim to characterize the system operating parameters for optimal use and consistency. For the QCM technique, the desired drug is first applied to a flat quartz crystal surface. During the test, the quartz crystal is oscillated. The frequency of oscillation is related to the amount of mass on the crystal surface and as the mass changes on the surface of crystal, the frequency will shift proportionally. For the test, a flow cell is attached atop of the crystal, allowing a liquid to pass over the drug to dissolve it. The change in frequency is recorded and the dissolution rate obtained. In order to validate this as a viable, effective method, a better understanding of the mass application process (amount of mass, area and shape of the film, etc.) to the surface of the crystal is needed. This is the emphasis of the efforts presented in this work