Nanoparticle drug delivery systems for inner ear therapy: an overview

Local drug delivery based on nanoparticles (NP) represents a novel strategy to improve inner ear treatments. The intratympanic delivery of NP may be suitable to treat or prevent hearing loss originating from damage to hair cells and spiral ganglion neurons in the cochlea. Numerous experimental studies support in vitro and in vivo the biocompatibility of NP, their physical stability, target specificity, cell/tissue uptake and ability to internalize therapeutic agents. The topical use of NP helps to reduce the amount of drug required and avoid systemic side effects. This review focuses on recent findings and applications of different NP systems locally delivered to the inner ear. The perspectives for clinical application of NP in inner ear drug delivery are also discussed.