Figure 4: Glucocorticoid concentrations in the cochlea in animal experimental studies
A: Data from two similar animal-experimental studies imply large variations in the perilymph concentrations of locally applied glucocorticoids (Bachmann et al. 2001 and Parnes et al. 1999,[138, 160]). As such the clinical usefulness of these findings is very restricted.
B: After considering the experimental differences between the two studies in the computer simulation, particularly regarding the artefacts from the sampling techniques, the pharmacokinetic profiles from the two studies could almost be brought to agreement (Plontke and Salt 2003,[183]). Consistent with model forecasts the concentrations in the basal turn in the guinea pig (B) appear to be similar to those in the basal turn of the human cochlea (C), since the diameters of the basal turn and the size of the round window membrane only differ a little. However, because of the longer length much lower concentrations are expected in the middle and apical turns in the human cochlea (C).