基于荧光探针内耳给药转运通路的考察

Transport Route of Fluorescent Probe via Inner Ear Administration

目的研究荧光探针经内耳给药后的转运通路。方法以香豆素-6为荧光探针,采用乳化-溶剂挥发法制备乳酸/羟基乙酸共聚物(PLGA)纳米粒,经单侧鼓室注射分别将其纳米粒及溶液剂导入豚鼠内耳,于不同时间点采集给药侧外淋巴液(PL)、对侧PL、脑脊液(CSF)和血浆,采用HPLC测定各组织中香豆素-6的浓度,并计算药动学参数。结果单侧鼓室注射纳米粒及溶液剂后,香豆素-6在给药侧PL、对侧PL及CSF中均有分布。与溶液剂相比,鼓室注射纳米粒后,香豆素-6在给药侧PL和CSF的AUC分别增加3.7、7.6倍,ρmax分别提高9.9、9.0倍,而且MRT分别延长5.1、9.4倍。结论内耳给药的转运途径为给药侧PL→CSF→对侧PL,并且采用纳米粒给药能显著提高内耳及CSF的局部生物利用度,延长作用时间。

OBJECTIVE To investigate transport route of fluorescent probe following inner ear administration. METHODS Coumarin-6 （CM） was employed as fluorescent probe and CM-loaded poly （lactie-co-glycolic acid） nanoparticles （CM-PLGA-NP） were prepared by emulsification-solvent evaporation method. Perilymph （PL）, eontralateral PL, cerebrospinal fluid （CSF） and plasma were collected periodically in guinea pigs after unilateral intratympanic administration of CM-PLGA-NP or CM solution. The concentrations of CM were determined by high performance liquid chromatography （ HPLC ）, and statistic program DAS was applied to the calculation of pharmacokinetic parameters. RESULTS CM was found in PL, contralateral PL and CSF after unilateral intratympanic administration of CM-PLGA-NP or CM solution. The AUC in PL and CSF following intratympanic administration of CM-PLGA-NP were respectively 3.7 and 7.6-fold higher than those following intratympanic adnlinistration of CM solution. And the Pmax in PL and CSF were respectively 9.9 and 9.0-fold higher. Moreover, CM-PLGA-NP extended the MRT in PL and CSF by 5. I and 9.4 times compared with CM solution. CONCLUSION Transport pathway of intra-cochlear adnlinistration is PL→CSF→contralateral PL. Nanoparticles can greatly improve drug distribution within the inner ear and CSF, and prolong the residence time.