[Distribution of gentamicin in inner ear after intratympanic gentamicin injection].
OBJECTIVE
To investigate uptake and accumulation of gentamicin by cells in the guinea pig inner ear after intratympanic injection using a fluorescent probe--gentamicin-Texas-red conjunction (GTTR).


METHODS
Adult guinea pigs (n = 80) were administered a single dose of GTrR to the middle ear cavity through the intact membrane and survived for 12 h, 24 h, 48 h, 3 d, 4 d, 7 d, 14 d and 28 d. The distribution of GTTR in the cochlear and vestibular cells was observed after staining with phalloidin-alexa-488. Texas Red and DMSO were injected into the tympanum as control.


RESULTS
Diffuse staining of gentamicin in the labyrinth was observed initially after local drug administration. At later time point the outer hair cells and sensory cells of vestibular organ were staining more densely than the support cells in the inner ear. The peak level of fluorescent density was reached 3 days after local injection. The GTTR was observed in the infracuticular zone.


CONCLUSIONS
GTTR was a potential fluorescent probe to investigate the pharmacokinetics and mechanisms of gentamicin accumulation in local application.
Liu
Jian-Ping
JP
Department of Otology and Skull Base, Eye Ear Nose and Throat Hospital, Fudan University, Shanghai 200031, China.
Dai
Chun-Fu
CF
Wang
Zheng-Min
ZM
Chi
Fang-Lu
FL
Tian
Jie
J
Da
Cui-Di
CD
D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000493:pharmacokinetics* / Q000633:toxicity; D007758:Ear, Inner / Q000378:metabolism*; D005456:Fluorescent Dyes; D005839:Gentamicins / Q000008:administration & dosage / Q000493:pharmacokinetics* / Q000633:toxicity; D006168:Guinea Pigs; D006198:Hair Cells, Auditory / Q000378:metabolism*
D000900:Anti-Bacterial Agents; D005456:Fluorescent Dyes; D005839:Gentamicins