Twist J N, Zatz J L
Rutgers University College of Pharmacy, Piscataway, NJ 08854.
J Pharm Sci. 1990 Jan;79(1):28-31. doi: 10.1002/jps.2600790108.
In this study the influence of paraben concentration on flux from solution in 1-propanol through polydimethylsiloxane membranes was investigated. Alcohol was sorbed by the polymer membrane leading to changes in membrane dimensions and increased membrane capacity to contain paraben (partition coefficient). Diffusion coefficients were not significantly influenced by alcohol sorption. Flux was increased 5-30 fold over nonimbibed donors such as water and polyols. An increase in paraben concentration reduced alcohol activity, its uptake by the membrane, and consequently the partition coefficient of paraben. As a result, flux increased with paraben concentration, reached a peak, and then declined. Maximal membrane concentration involves a trade-off between alcohol-membrane interaction (solvent activity) and paraben concentration, and occurred at paraben concentrations in the range of 1.3 to 1.4 mmol/g. At equimolar concentrations, flux was highest for methylparaben and declined as the series was ascended. Differences in flux between parabens at a specified molar concentration were due only to differences in diffusivity.
在本研究中，考察了对羟基苯甲酸酯浓度对1-丙醇溶液中对羟基苯甲酸酯透过聚二甲基硅氧烷膜通量的影响。聚合物膜会吸附醇，导致膜尺寸发生变化，并增加膜容纳对羟基苯甲酸酯的能力（分配系数）。扩散系数不受醇吸附的显著影响。与未吸收醇的供体（如水和多元醇）相比，通量增加了5至30倍。对羟基苯甲酸酯浓度的增加降低了醇的活性、其被膜的吸收量，从而降低了对羟基苯甲酸酯的分配系数。结果，通量随对羟基苯甲酸酯浓度增加而升高，达到峰值后下降。最大膜浓度涉及醇与膜相互作用（溶剂活性）和对羟基苯甲酸酯浓度之间的权衡，且在对羟基苯甲酸酯浓度为1.3至1.4 mmol/g范围内出现。在等摩尔浓度下，对羟基苯甲酸甲酯的通量最高，并随着同系列的上升而下降。特定摩尔浓度下对羟基苯甲酸酯之间通量的差异仅归因于扩散率的差异。
