Al-Omar M, Al-Majed A, Sultan M, Gadkariem E A, Belal F
Department of Pharmaceutical Chemistry, College of Pharmacy, King Saud University, P.O. Box 2457, Riyadh 11451, Saudi Arabia.
J Pharm Biomed Anal. 2005 Feb 7;37(1):199-204. doi: 10.1016/j.jpba.2004.10.011.
The voltammetric behaviour of danazol DZ (antigonadotropin) was studied using cyclic voltammetry, direct current, differential pulse polarography (DPP) and alternating current polarography. Danazol exhibited irreversible cathodic waves over the pH range of 1-5 in Britton Robinson buffers. At pH 1 (the analytical pH), a well-defined wave with E1/2 of -1.04 V versus Ag/AgCl reference electrode was obtained. The diffusion current constant (Id) was 4.8+/-0.14 microA.L.m mole(-1) and the current-concentration plot was rectilinear over the range from 5 x 10(-6) to 1 x 10(-4) M with correlation coefficient (n = 11) of 0.995. The calculated detection limit was 1 x 10(-6) M using the DPP mode. The wave was characterized as being irreversible, diffusion-controlled although adsorption phenomenon played a limited role in the electrode process. The proposed method was applied to commercial capsules and the average percentage recovery was in agreement with that obtained by the official USP method. The method was extended to the in vitro determination of DZ in spiked human urine and plasma samples, the percentage recoveries were 96+/-4 and 97+/-5, respectively. A proposal of the electrode reaction was postulated.
采用循环伏安法、直流极谱法、差分脉冲极谱法（DPP）和交流极谱法研究了达那唑（DZ，抗促性腺激素）的伏安行为。在 Britton Robinson 缓冲液中，达那唑在 pH 值为 1 - 5 的范围内呈现不可逆的阴极波。在 pH 为 1（分析用 pH 值）时，相对于 Ag/AgCl 参比电极，得到了一个半波电位 E1/2 为 -1.04 V 的清晰波峰。扩散电流常数（Id）为 4.8±0.14 μA·L·mmol⁻¹，电流 - 浓度曲线在 5×10⁻⁶ 至 1×10⁻⁴ M 的范围内呈直线关系，相关系数（n = 11）为 0.995。使用 DPP 模式计算得到的检测限为 1×10⁻⁶ M。该波的特征为不可逆、受扩散控制，尽管吸附现象在电极过程中起的作用有限。所提出的方法应用于市售胶囊，平均回收率与美国药典官方方法得到的结果一致。该方法还扩展到了加标人尿和血浆样品中 DZ 的体外测定，回收率分别为 96±4 和 97±5。同时提出了电极反应的假设。
