Pharrnacokinetics of antibiotics in the middle ear

Abstract

The middle ear mucosa is described as a non-specialized site where drug substances diffuse passively. However, precise pharmacokinetic studies on antibiotic penetration into middle ear effusion (MEE) are difficult to conduct in humans because of ethical and methodological problems: (1) studies must involve the population in which acute otitis media (AOM) is most frequent (i.e. in children from 3 months to 3 years of age); (2) studies are commonly performed during surgery for chronic otitis media with effusion, whereas drug penetration into MEE is higher during AOM; (3) kinetics are deduced from data per individual obtained in groups with marked interindividual variations. Furthermore, the results of different studies are difficult to compare because of differences in protocols, antibiotic assay methods and interpretation. Clinical studies have nonetheless shown the poorly predictive nature of serum concentrations, given thelarge differences in drug delivery to the MEE among antibiotic classes, among members of the same class, and among individuals receiving a given antibiotic. Experimental studies can help to narrow the gap between in vitro and clinical data, as the more precise pharmacokinetic data they yield can throwlight on thelink between drug/host/pathogen factors and bacteriologic efficacy.