Ribeiro David S M, Prior João A V, Santos João L M, Lopes João A, Lima José L F C
REQUIMTE, Serviço de Química-Física, Faculdade de Farmácia da Universidade do Porto, Rua Aníbal Cunha no. 164, 4050-047 Porto, Portugal.
Talanta. 2009 Sep 15;79(4):1161-8. doi: 10.1016/j.talanta.2009.02.052. Epub 2009 Mar 9.
The oxidative coupling reaction between aromatic amines and 3-methylbenzothiazolin-2-one hydrazone (MBTH) in the presence of cerium(IV) has been extensively used with quantitative analytical purposes. Nevertheless, a literature survey reveals that different wavelengths (visible range) can be used to monitor the reaction products when using MBTH and Ce(IV) as colour developing reagents. In the present work, the oxidative coupling reaction of indapamide (an oral antihypertensive diuretic drug) with MBTH in the presence of cerium(IV) was evaluated using distinct reaction approaches and was implemented in an automated multipumping flow system. The developed methodology was applied in the spectrophotometric control of the drug in pharmaceutical formulations. The optimization of the proposed multipumping flow system was performed by using an experimental design approach, namely by exploiting a Plackett-Burman factorial design and a central cubic faces design. This work revealed the formation of products with different reaction kinetics, chemical stabilities and absorbance spectra, depending on the sequence of addition of the reagents. By exploiting a specific sequence in the addition of reagents, the proposed automatic system allowed the rapid quantification of indapamide in pharmaceutical formulations, with a determination rate of about 25 h(-1), and a relative deviation under 2.1% when comparing with the reference procedure. Detection limit was approximately 1 mg L(-1).
在铈（IV）存在下，芳香胺与3 - 甲基苯并噻唑啉 - 2 - 酮腙（MBTH）之间的氧化偶联反应已被广泛用于定量分析目的。然而，文献调查显示，当使用MBTH和铈（IV）作为显色试剂时，可使用不同波长（可见光范围）来监测反应产物。在本工作中，使用不同的反应方法评估了吲达帕胺（一种口服抗高血压利尿药）在铈（IV）存在下与MBTH的氧化偶联反应，并在自动多泵流动系统中实现。所开发的方法应用于药物制剂中药物的分光光度控制。通过实验设计方法，即利用Plackett - Burman析因设计和中心立方体面设计，对所提出的多泵流动系统进行了优化。这项工作揭示了根据试剂添加顺序形成具有不同反应动力学、化学稳定性和吸收光谱的产物。通过利用特定的试剂添加顺序，所提出的自动系统能够快速定量药物制剂中的吲达帕胺，测定速率约为25 h⁻¹，与参考方法相比相对偏差在2.1%以下。检测限约为1 mg L⁻¹。
