Kowaluk E A, Roberts M S, Polack A E
J Pharm Sci. 1986 Jun;75(6):562-70. doi: 10.1002/jps.2600750608.
Aqueous solutions of several ionizable substances were stored in plastic infusion bags and the sorption of the substances monitored with time. The substances used were p-nitrophenol, p-toluidine, warfarin sodium [3-(alpha-acetonylbenzyl)-4-hydroxycoumarin sodium salt] and trifluoperazine hydrochloride (10-[3-(4-methyl-1-piperazinyl)propyl]-2-(trifluoromethyl)phenothiazine dihydrochloride). The rate and extent of sorption for each substance varied with pH and was consistent with a preferential uptake of the un-ionized species. The uptake of p-nitrophenol and p-toluidine was adequately described by a diffusion model derived assuming that sorption is rate-controlled by the diffusivity of the solute in the plastic matrix, and that only the un-ionized species was sorbed by the plastic matrix. However, the uptake of warfarin sodium and trifluoperazine hydrochloride was described more accurately by a diffusion model in which the diffusional resistance of the plastic matrix and of an interfacial resistance barrier both contributed to the diffusional resistance encountered in the sorption process. It appeared that the rate of uptake of the un-ionized form of these solutes was diminished due to the influence of interfacial or aqueous diffusional barriers. Solute lipophilicity and degree of ionization appeared to be important factors determining the relative contribution of the respective barriers to the overall diffusional resistance.
将几种可电离物质的水溶液储存在塑料输液袋中，并随时间监测这些物质的吸附情况。所使用的物质有对硝基苯酚、对甲苯胺、华法林钠[3-(α-丙酮基苄基)-4-羟基香豆素钠盐]和盐酸三氟拉嗪(10-[3-(4-甲基-1-哌嗪基)丙基]-2-(三氟甲基)吩噻嗪二盐酸盐)。每种物质的吸附速率和程度随pH值而变化，并且与未电离形式的优先摄取一致。假设吸附速率受溶质在塑料基质中的扩散率控制，且只有未电离形式的物质被塑料基质吸附，由此推导出的扩散模型能够充分描述对硝基苯酚和对甲苯胺的摄取情况。然而，对于华法林钠和盐酸三氟拉嗪的摄取情况，采用一个扩散模型能更准确地描述，在该模型中，塑料基质的扩散阻力和界面阻力屏障都对吸附过程中遇到的扩散阻力有贡献。似乎由于界面或水相扩散屏障的影响，这些溶质未电离形式的摄取速率降低。溶质的亲脂性和电离程度似乎是决定各个屏障对总扩散阻力相对贡献的重要因素。
