Monitoring drug release from electrospun fibers using an in situ fiber-optic system

Electrospun fiber mats are currently gaining attention as advanced drug delivery systems. Dissolution testing for such systems is generally performed in small vials by immersing the fiber mats in buffered solutions. Defined aliquots of dissolution medium are withdrawn at predefined time points, and the dissolved drug is quantified. However, this procedure is associated with several drawbacks. The method is not automated, and as such requires manual sampling, which potentially leads to inaccuracies particularly in frequent sampling intervals as required for characterization of rapid drug release. Further, the sheet-like fiber mats tend to partially fold upon contact with the dissolution medium, which may potentially affect the release kinetics and reproducibility of the acquired release data. In this study, we investigated the application of a fully automated fiber-optics based dissolution testing system for in situ monitoring of drug release from electrospun fiber mats. Electrospun poly(vinyl alcohol) fibers loaded with lysozyme were used as a model system. To prevent folding of the fiber mats and ensure a fixed position in the dissolution vessel throughout the experiment, a flexible adapter was developed to allow for the attachment of the fiber mats to the vessel walls. Lysozyme release from the fiber mats was compared with the release from cast films with the same composition. Even though the release processes were rather fast and differences in release kinetics of the two systems were marginal, the fiber-optics based dissolution setup allowed for the successful detection of released protein in both cases. The present study, therefore, highlights the potential for the utilization of fully automated fiber-optics based dissolution testing systems for advanced in situ monitoring of drug release from electrospun fibers.