Comparison of the distribution pattern of PEG-b-PCL polymersomes delivered into the rat inner ear via different methods

Abstract

Conclusion: Cochleostomy is the most efficient approach in delivering PEG-b-PCL polymersomes (PMs) to the inner ear. PMs can be delivered to the vestibule by transtympanic injection or cochleostomy. Objective: To evaluate the efficiency of delivering PEG-b-PCL PMs into the inner ear using different approaches. Methods: The PEG-b-PCL PMs were administered either by sustained topical round window membrane (RWM) delivery using gelatin sponge pledgets in combination with an osmotic pump, transtympanic injection, or cochleostomy. The distribution of the PMs in the inner ear was observed by confocal microscopy using either whole mount specimens or cryosections. Results: Cochleostomy resulted in distribution of the PMs in the spiral ligament (SL), mesothelial cells beneath the organ of Corti, supporting cells in the organ of Corti, and spiral ganglion cells (SGCs). Transtympanic injection induced uptake of the PMs in the SL and mesothelial cells beneath the organ of Corti. Topical administration showed distribution of the PMs only in the SL. In the vestibulum, transtympanic injection and cochleostomy induced more distribution of the PMs than did topical RWM delivery (p < 0.05, Kruskal-Wallis test).

Keywords::

• Drug delivery
• nanocarrier
• imaging
• animal

Acknowledgments

This study was supported by the European Community 6th Framework Programme on Research, Technological Development and Demonstration (Nanotechnology-based Targeted Drug Delivery. Contract number: NMP4-CT-2006-026556, Project acronym: NANOEAR).

Declaration of interest: The authors report no conflicts of interest. The authors are responsible for the content and writing of the paper.