Figure 5: Location- and time-dependent methyl-prednisolone concentration in the scala tympani after intratympanic application
Calculation of methyl-prednisolone concentration in the scala tympani of the guinea pig cochlea after single application without volume stabilization reveals high peak concentrations at an early stage after the onset of application. The marked baso-apical concentration gradient is clearly recognizable. An even concentration distribution in the cochlea is first achieved only very late on and at a very low level (blue) compared to the peak concentration (red). The target structure in the cochlea, the relative vestibular-cochlear toxicity and the therapeutic range/index of the medication must therefore be considered especially with local application of medication to the round window membrane (data from Plontke and Salt 2003,[183]).