Purpose:
Due to the complications associated with intravitreal injection novel drug delivery technologies are desired. We have developed planar SU-8/PEGDMA microdevices, coated with the permeation enhancer Chitosan. These devices maximize contact surface area and provide consistent drug volume. Using the retinal epithelial cell line ARPE19, the influence of microdevice geometry and surface coating on paracellular drug delivery has been investigated.
Methods:
Device fabrication was achieved by a three-mask photolithography process. SU-8 and PEGDMA hydrogel solutions of FITC-Dextran (FD) or Lucentis were spun onto a silicon wafer. UV-light was used to crosslink the hydrogel in the device reservoir. Surface modification was conducted by deposition of a 1.6% w/v Chitosan solution onto a drug-loaded wafer until dry film formation. Devices were placed in the apical chamber of an ARPE19 coated transwell insert. Aliquots were removed from the basolateral chamber and analyzed for released drug concentration using a fluorimeter or spectrophotometer.
Results:
Microdevices with payloads of FD and Lucentis were succesfully fabricated. Consistent elution of FD and Lucentis from devices was achieved. The quantity of FD transported across the ARPE19 monolayer of cells using a microdevice was greater than the amount transported using a bolus administration. The effect Chitosan coating has on the amount of drug transported is still being investigated and further optimization of the coating process will clarify if the mucoadhesive inhibits drug elution.
Conclusions:
A planar microdevice capable of housing therapeutics of varying molecular weight was developed. Preliminary data suggests this device enhances the transport of large molecules across an ARPE19 in vitro retina model in comparison to bolus administration alone.
Keywords: retinal pigment epithelium