Single-photon emission computed tomography (SPECT) imaging using intravenous radioactive ligand administration to indirectly evaluate the time-dependent effect of intranasal drugs with poor blood-brain barrier permeability on brain drug distributions in mice was evaluated. The biodistribution was examined using domperidone, a dopamine D2 receptor ligand, as the model drug, with intranasal administration at 0, 15, or 30 min before intravenous [123I]IBZM administration. In the striatum, [123I]IBZM accumulation was significantly lower after intranasal (IN) domperidone administration than in controls 15 min after intravenous [125I]IBZM administration. [123I]IBZM SPECT was acquired with intravenous (IV) or IN domperidone administration 15 min before [123I]IBZM, and time–activity curves were obtained. In the striatum, [123I]IBZM accumulation was clearly lower in the IN group than in the control and IV groups. Time–activity curves showed no significant difference between the control and IV groups in the striatum, and values were significantly lowest during the first 10 min in the IN group. In the IN group, binding potential and % of receptor occupancy were significantly lower and higher, respectively, compared to the control and IV groups. Thus, brain-migrated domperidone inhibited D2R binding of [123I]IBZM. SPECT imaging is suitable for research to indirectly explore nose-to-brain drug delivery and locus-specific biological distribution.
本文评估了单光子发射计算机断层扫描(SPECT)成像技术,使用静脉注射放射性配体来间接评估鼻内给药对小鼠脑药物分布的时间依赖性影响。该研究使用多巴胺D2受体配体多潘立酮作为模型药物,通过鼻内给药在静脉注射[123I]IBZM之前0、15或30分钟进行生物分布研究。在纹状体中,与对照组相比,静脉注射[125I]IBZM后15分钟,鼻内给药多潘立酮显著降低了[123I]IBZM的积累。使用静脉注射或鼻内给药多潘立酮在[123I]IBZM注射前15分钟进行[123I]IBZM SPECT成像,并获得时间-活性曲线。在纹状体中,鼻内给药组的[123I]IBZM积累明显低于对照组和静脉注射组。时间-活性曲线显示,在纹状体中,对照组和静脉注射组之间没有显著差异,而鼻内给药组的值在前10分钟内显著最低。在鼻内给药组中,结合潜力和受体占据率显著低于对照组和静脉注射组。因此,脑内移行的多潘立酮抑制了[123I]IBZM的D2R结合。SPECT成像技术适用于间接探索鼻-脑药物递送和定位特异性生物分布的研究。