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Round Window Gentamicin Absorption: An In Vivo Human Model
Author(s) -
Becvarovski Zoran,
Bojrab Dennis I.,
Michaelides Elias M.,
Kartush Jack M.,
Zappia John J.,
LaRouere Michael J.
Publication year - 2002
Publication title -
the laryngoscope
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.181
H-Index - 148
eISSN - 1531-4995
pISSN - 0023-852X
DOI - 10.1097/00005537-200209000-00015
Subject(s) - round window , gentamicin , cerebrospinal fluid , in vivo , aminoglycoside , middle ear , antibiotics , inner ear , absorption (acoustics) , medicine , chemistry , anatomy , pathology , biology , biochemistry , physics , optics , microbiology and biotechnology
Objective/Hypothesis Using a novel human labyrinthine sampling model, in vivo gentamicin absorption through the round window can be measured. Study Design A prospective study. Methods Gentamicin was delivered either transtympanically (preoperative) or through a facial recess approach (intraoperative). The lateral semicircular canal and vestibule were opened, and by means of a microsyringe, labyrinthine fluid was aspirated. A sample of serum was also drawn. In all patients cerebrospinal fluid was also drawn. The samples were analyzed using a standard chemistry analyzer. Results Intratympanic gentamicin diffused through the round window membrane and achieved concentrations in the labyrinthine fluid ranging from 0 to 16 mg/L. Intratympanic gentamicin was absorbed into the systemic circulation in 4 of 11 patients with serum levels ranging from 0.3 to 0.4 mg/L. No gentamicin was detected in the cerebrospinal fluid. Conclusions Intratympanic gentamicin diffuses rapidly through the round window membrane and achieves significant levels in the inner ear. Thus, this new model can be used to assess round window permeability to clinically relevant medications such as steroids and ototopical antibiotics.