Cheung A P, Mavar R, Carlson C, Chiang W K
Life Sciences Division, SRI International, Menlo Park, CA 94025.
J Pharm Biomed Anal. 1991;9(1):41-5. doi: 10.1016/0731-7085(91)80235-2.
A liquid chromatogrpahic (LC) assay was recommended by the Food and Drug Administration of the United States for the uptake and release study of chlorhexidine digluconate (CHDG) in ophthalmic solutions by contact lenses. The results from this and other reversed-phase LC assays of CHDG were inaccurate when the working standard and sample solution matrices were different. The error was caused by binding of the analyte onto the container surface and LC column packings. The loss of chlorhexidine due to binding was dependent upon, and very sensitive to, the counter ions in the sample solutions. Relative to water solutions of CHDG, solutions containing chloride, thiosulphate and edetate reduced the loss of the analyte, while solutions containing borate enhanced the loss. To assay CHDG reliably with reversed-phase LC, the media of the working standard and the sample solutions should be closely matched.
美国食品药品监督管理局推荐采用液相色谱（LC）分析法研究隐形眼镜对眼科溶液中葡萄糖酸洗必泰（CHDG）的摄取和释放情况。当工作标准品和样品溶液基质不同时，该方法以及其他CHDG反相LC分析法的结果不准确。误差是由分析物与容器表面和LC柱填料的结合所致。洗必泰因结合而损失的量取决于样品溶液中的抗衡离子，且对其非常敏感。相对于CHDG水溶液，含氯离子、硫代硫酸盐和依地酸盐的溶液可减少分析物的损失，而含硼酸盐的溶液则会增加损失。为了用反相LC可靠地测定CHDG，工作标准品和样品溶液的介质应紧密匹配。
