AIDS encephalopathy is an insidious complication of human immunodeficiency virus infection which is difficult to treat because of the poor uptake of many potentially useful antiretroviral drugs through the blood-brain barrier. A chemical delivery system (CDS) for zidovudine (AZT) based on redox trapping within the brain has been prepared and tested in several animal models to circumvent this limitation. The behavior of the AZT-CDS in the dog was considered. Parenteral administration of AZT resulted in rapid systemic elimination and poor uptake by the central nervous system. Ratios of the area under the concentration-time curve of AZT for cerebrospinal fluid to that for blood were 0.32, and ratios of the area under the concentration-time curve of AZT for brain to that for blood were approximately 0.25. Administration of an aqueous formulation of the AZT-CDS resulted in rapid tissue uptake and conversion of the CDS to the corresponding quaternary salt with the subsequent production of AZT. Delivered in this way, the levels of AZT in brain were 1.75- to 3.3-fold higher than those associated with conventional AZT administration. In addition, the levels of AZT in blood were 46% lower than those associated with AZT administration. The higher concentrations in brain and lower concentration in blood combined to significantly increase the ratio of the concentration of AZT in the brain to that in blood after AZT-CDS administration compared to that after AZT dosing.
艾滋病脑病是人类免疫缺陷病毒感染的一个隐匿并发症,由于许多潜在有用的抗逆转录病毒药物在血脑屏障上的吸收较差,治疗起来很困难。一种基于脑内氧化还原捕获的阿司匹林(AZT)的化学递送系统(CDS)已经制备并在几种动物模型中进行了测试,以规避这种限制。研究了AZT-CDS在狗中的行为。静脉给药AZT导致快速的系统消除和中枢神经系统的吸收不良。脑脊液中AZT浓度-时间曲线下面积与血液中的比值为0.32,脑中AZT浓度-时间曲线下面积与血液中的比值约为0.25。给予AZT-CDS的水剂制剂导致组织快速吸收,并将CDS转化为相应的季铵盐,随后产生AZT。以这种方式给药,脑中的AZT水平比传统AZT给药方式高1.75到3.3倍。此外,血液中的AZT水平比AZT给药时低46%。脑中的更高浓度和血液中的更低浓度结合在一起,显著增加了AZT-CDS给药后脑内AZT浓度与血液中AZT浓度之比,相比AZT给药后的情况。