Dionne V E
Biophys J. 1976 Jul;16(7):705-17. doi: 10.1016/S0006-3495(76)85723-2.
The iontophoretic release of drugs from micropipettes into free (Ringer's) solution was described using an ion-selective microelectrode assay method. This characterization, with a temporal resolution of 20 ms, showed that the equilibrium rate of drug transport was not linearly proportional to release current; the departure from linearity was increased by backing current and the result was demonstrated with analytically derived drug release functions. The general relation between the drug transport rate and release current was independent of the specific drug or pipette resistance; no functional relation was observed that might quantitatively predict this dependence without prior use of the assay. The diffusion coefficients at 25 degrees C in frog Ringer's of the drugs used in this study, all neuromuscular agonists, were determined: all values X 10(6) cm2/s; acetylcholine 6.11 +/- 0.30; carbamylcholine 7.44 +/- 0.34; 3-(m-hydroxyphenyl) prophyltrimethyl ammonium 5.79 +/- 0.13.
采用离子选择性微电极测定法描述了药物从微量移液器向游离（林格氏）溶液中的离子电渗释放。这种具有20毫秒时间分辨率的特性表明，药物转运的平衡速率与释放电流并非线性比例关系；反向电流会增加与线性关系的偏差，并且通过分析推导的药物释放函数证明了该结果。药物转运速率与释放电流之间的一般关系与特定药物或移液器电阻无关；未观察到在不预先使用该测定法的情况下可能定量预测这种依赖性的功能关系。测定了本研究中使用的所有神经肌肉激动剂药物在25℃青蛙林格氏液中的扩散系数：所有值×10(6)平方厘米/秒；乙酰胆碱6.11±0.30；氨甲酰胆碱7.44±0.34；3 -（间羟基苯基）丙基三甲基铵5.79±0.13。
