Pharmaceuticals used for otic indication or that may have otic toxicity such as chemotherapy agents or aminoglycocides may accumulate in the peri-lymph which accumulates in the cochlea. The volume of the cochlea in small animals is very small and may be in the 10-20 ul range. However, collection of the perilymph is a difficult micro-technique. At CBI, we have optimized and perfected this techique and can now offer otic pharmacokinetics of the cochlear perilymph in guinea pigs.