Colburn W A, Ehrenkranz R A
Pediatr Pharmacol (New York). 1983;3(1):7-14.
The pharmacokinetics of parenterally administered vitamin E (d, l-alpha tocopherol) in serum were developed using data from five premature neonates (1,500 +/- 100 gm) receiving a single 20 mg/kg intramuscular injection. Blood samples were obtained immediately prior to drug administration to establish baseline vitamin E concentrations: then further sampling was performed at various intervals for up to 7 days. It was assumed that dietary intake of vitamin E did not markedly alter serum concentration of vitamin E during the 7-day study and that the total intramuscular dose was absorbed. Although extensive sampling could not be performed in any one neonate, composite sampling from the study population made it possible to construct a pharmacokinetic profile of vitamin E in premature neonates. The half-life of elimination was 44 hours, the volume of distribution (V beta) was 0.41 liter/kg. and serum clearance was 6.5 ml/hr/kg. Vitamin E is an important biological antioxidant that may provide protection to the retinas and lungs of premature infants exposed to supplemental inspiratory oxygen. Therefore, if the pharmacokinetics of vitamin E observed in the present study can be generalized to the population of premature infants, a single 10 mg/kg intramuscular (IM) loading dose followed by 5 mg/kg every 48-72 hours should maintain serum concentration of 1.5 to 2.5 mg%--a level that has been associated with antioxidant protection.
利用5名接受单次20mg/kg肌肉注射的早产新生儿（体重1500±100克）的数据，建立了肠胃外给药维生素E（d，l-α生育酚）在血清中的药代动力学。在给药前即刻采集血样以确定维生素E的基线浓度；然后在长达7天的时间内每隔不同时间进行进一步采样。假定在为期7天的研究中维生素E的饮食摄入量不会显著改变血清维生素E浓度，且肌肉注射的总剂量被吸收。尽管无法对任何一名新生儿进行广泛采样，但来自研究人群的综合采样使得构建早产新生儿维生素E的药代动力学概况成为可能。消除半衰期为44小时，分布容积（Vβ）为0.41升/千克，血清清除率为6.5毫升/小时/千克。维生素E是一种重要的生物抗氧化剂，可能为暴露于吸入性补充氧气的早产婴儿的视网膜和肺部提供保护。因此，如果本研究中观察到的维生素E药代动力学能够推广到早产婴儿群体，单次10mg/kg肌肉注射负荷剂量，然后每48 - 72小时注射5mg/kg，应能维持血清浓度在1.5至2.5mg%——这一水平与抗氧化保护相关。
