目的建立豚鼠外耳淋巴液中磷酸地塞米松的含量测定方法。方法采用听泡灌注给药,在给药结束后30 min采集鼓阶外淋巴液,应用高效液相色谱仪测定磷酸地塞米松的含量。HPLC色谱条件为ZORBAX Eclipse XDB-C₁₈色谱柱(4.6 mm×250 mm,5μm),流动相为7.56 mmol·L^-1硫酸铵-乙腈(70∶30),流速1.0 mL·min^-1,柱温20℃,紫外检测波长239 nm。结果磷酸地塞米松的线性范围为0.10～4.8 mg·L^-1(r=0.999 8)。最低检测限为6.25μg·L^-1,日内和日间RSD分别为2.17%和3.25%。结束给药30 min后鼓阶外淋巴液中磷酸地塞米松的浓度为2.20 mg·L^-1。结论方法灵敏、准确,重现性好,可用于外淋巴液中磷酸地塞米松的测定。

OBJECTIVE To establish a method for determining the concentration of dexamethasone phosphate in the perilymph of guinea pig. METHODS Typmpanic cavity was infused with dexamethasone phosphate solution,the perilymph of the scala tympani was sampled at 30 min after an administrations.Dexamethasone phosphate in the samples was assayed by HPLC.A separation was performed on a ZORBAX Eclipse XDB-C₁₈ column with 7.56 mmol·L^-1 ammonium sulfate-acetonitrile(70∶30) as mobile phase at the flow rate of 1.0 mL·min^-1.The temperature of column was at 20 ℃,the wavelength of detection was 239 nm.RESULTS The calibration curve was linear within the concentration range of 0.10～4.8 mg·L^-1(r=0.999 8),the limit of detection was 6.25 μg·L^-1,the RSD values of interday and intraday ralidation were 2.17% and 3.25%.The concentration of dexamethasone phosphate in the perilymph of the scala tympani was 2.20 mg·L^-1 at 30 min after administration.CONCLUSION The method appears to be simple,accurate,reproducible and can be used to determine the concentration of dexamethasone phosphate in perilymph.