Table 2.

Studies attempting to deliver actual drugs to the inner ear using nanoparticles.

Nanoparticle	Size of nanoparticle	Animal	Administration route	Loaded drug or gene	Evaluation time	Evaluation of nanoparticle uptake
PEG-PLA NP [22]	Not described	Guinea pig, deafened with cisplatin	Intraperitoneal	Dexamethasone	At 3 days	ABR and morphology
PEG-PLA NP [23]	130 ± 4.78 nm	Guinea pig, deafened with cisplatin	Intratympanic	Dexamethasone	At 3 days	ABR and morphology
Multimicellar NP [24]	120.8~159.9 nm	Wistar rats, deafened with cisplatin	Intratympanic	6α-methylprednisolone	At 3 days	ASSR
PLGA NP [25]	135 nm with a PDI of 0.17	Guinea pigs	Intratympanic	Salvianolic acid B, tanshinone IIA, and total panax notoginsenoside	At several predetermined time points within 96 h	HPLC of perilymph
PLGA NP [26]	154 nm with PDI 0.007	Guinea pigs	Intratympanic	Salvianolic acid B, tanshinone IIA, and total panax notoginsenoside	At several predetermined time points within 36 h	HPLC of blood, perilymph, CSF, and brain tissue
PLGA-magnetite-NP [27]	482.8 ± 158 nm	Guinea pigs	Intratympanic	Dexamethasone acetate	At 30 min	HPLC of perilymph, RWM, and inner ear tissue
Cubic liquid crystalline NP [28]	138.6~210.9 nm	Guinea pigs	Intratympanic	Earthworm fibrinolytic enzyme	At several predetermined time points within 24 h	Fluorescence microscope and spectrophotometer

NP: nanoparticle; ABR: auditory brainstem response; PEG-PLA: polyethylene glycol-coated polylactic acid; ASSR: auditory steady-state responses; RWM: round window membrane.