Examination of steroid release from screw-in pacing leads.

Although constant progress in pacing lead design and life time of pacemaker battery has contributed to the clinical success of this treatment option, the mechanism of drug release from steroid-eluting pacing leads is not completely understood. Besides, drug concentrations of steroids released into the heart-tissue remain unclear. Therefore, three different dissolution test methods were examined: a non-standardized (reagent tube), a compendial USP (paddle) and a hydrogel method. The experimental results indicate that dissolution from pacing leads is governed by a diffusion-controlled mechanism and occurs over a prolonged time. Furthermore, the integration of a hydrogel compartment seemed to have an impact on drug release leading to a decrease in release rate. Nevertheless, the experimental results emphasize different experimental parameters in dissolution testing may have a distinct influence on drug dissolution.