Drug permeability across ocular membranes is crucial factor in ocular drug delivery after local and systemic delivery. ODDL has several membrane models for the anterior eye segment, such as differentiated corneal and conjunctival cells and isolated cornea, conjunctiva and sclera from rabbit, porcine and bovine eyes. Cell studies are performed using Transwell systems and isolated tissues are investigated using Ussing chambers with possibilities for electrophysiological readings with voltage clamp instrument. Posterior segment barriers are investigated by using various retinal pigment epithelial models (ARPE-19 cultures, human primary cell cultures, and isolated RPE-choroid specimens). The analytical systems are case dependent: the options include liquid chromatography, LC/MS (liquid chromatography-mass spectrometry), and analytics based on fluorescence and radioactivity.
Cellular uptake and binding of drugs are studied with primary cells or secondary cell lines. Several ocular cell types are available (e.g. corneal epithelium, conjunctival epithelium, RPE). Total drug quantities and free fraction as well as metabolism and drug release from conjugates and prodrugs can determined. Furthermore, binding equilibria studies with other ocular components, such as lens, vitreous, and melanin are available. ODDL has also experience on mechanistic studies about the role of active drug transport as well as determination of protein expression in ocular cell models.
Expertise of ODDL also allows extension of permeability and binding data to the in vivo context with predictive pharmacokinetic simulations.