Pharmacokinetic profiles of methylprednisolone concentration in perilymph and plasma of guinea pig following local administration / 中华耳鼻咽喉头颈外科杂志

ABSTRACT

<p><b>OBJECTIVE</b>To determine pharmacokinetics profiles of methylprednisolone (MTH) in perilymph and plasma of guinea pig after intratympanic injection of MTH in different concentrations.</p><p><b>METHODS</b>By auripuncture, three different concentrations of MTH were used in guinea pigs 32.0 mg/ml, 40.0mg/ml and 62.5 mg/ml. Samples of plasma and perilymph of the scala tympani were collected at 1-12 h after administration and the concentrations of MTH were assayed using high-performance liquid chromatography. Auditory brainstem response (ABR) was detected before and 12h after MTH administration.</p><p><b>RESULTS</b>The concentrations of MTH in perilymph were dose-related. The differences of MTH concentrations in perilymph before and at series sampling time after administration were significant in statistics (P < 0.05), except for the intervals of 5 h, 6 h and 12 h. In addition, the concentration of MTH in perilymph was the highest in 62.5 mg/ml group. No MTH was detected in plasma after local administration, except for 1.5 h and 2 h after administration with 62.5 mg/ml. There were not differences in the thresholds of wave III of ABR before and 12h after local MTH administration among three groups (P > 0.05).</p><p><b>CONCLUSIONS</b>The experimental results indicates that the concentration of 62.5 mg/ml of MTH is optimal for treatment inner ear diseases by intratympanic administration among three groups, it get a high concentration in perilymph and not effect on the function of inner ear.</p>