The cochlea of the inner ear has fluid filled spaces. Drugs are delivered to the cochlea via transtympanic injections to the base of the cochlea, at a membrane called the Round Window Membrane (RWM). Drugs diffuse through the RWM into the cochlear fluids. This method relies on the mechanism of pure diffusion. Hence drug delivery is slow and treatment efficacy is affected. The cochlear fluid oscillates when stimulated by sound. This thesis experimentally investigates if drug dispersion in the cochlea can be enhanced by oscillating the cochlear fluids for amplitudes as small as that of the cochlea.
To answer this question, empirical dye dispersion experiments for oscillating flows were performed in a cylindrical tube over a range of frequencies and amplitudes of oscillation. An experimental apparatus was designed and assembled to conduct experiments on the dispersion of a dye in water. Experiments were conducted for 3 sets of frequencies for amplitudes varying from 0 (pure diffusion) to 2.5 times the radius of the cylindrical tube. A time series of images of the dye were used to measure concentration and ultimately used to calculate an effective diffusion coefficient and to quantify the enhancement in diffusion.
Dispersion coefficients obtained for a constant frequency increase linearly as a function of the square of the amplitude, and for a constant amplitude dispersion coefficients increase with frequency. These trends agree with previously established results from literature. The results of the experiments, when scaled to the cochlea and feasible magnitudes of oscillation, predict that oscillation does not substantially enhance diffusion.
Library of Congress Subject Headings
Drug delivery systems--Testing; Fluid mechanics; Cochlea--Mechanical properties
Dasgupta, Siddharth, "An Experimental Study of Dispersion in Oscillating Flows in Cylindrical Tubes" (2015). Thesis. Rochester Institute of Technology. Accessed from
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