Garcia Luane Ferreira, da Cunha Carlos Eduardo Peixoto, Moreno Emily Kussmaul Gonçalves, Vieira Thomaz Douglas, Lobón Germán Sanz, Luque Rafael, Somerset Vernon, de Souza Gil Eric
Faculdade de Farmácia, Universidade Federal de Goiás, Goiânia, GO 74690-970, Brazil.
Departamento de Química Orgánica, Universidad de Cordoba, Cordoba E14014, Spain.
Pharmaceuticals (Basel). 2018 Oct 5;11(4):99. doi: 10.3390/ph11040099.
Methyldopa is a catecholamine widely used in the treatment of mild to moderate hypertension whose determination in pharmaceutical formulae is of upmost importance for dose precision. Henceforth, a low-cost carbon paste electrode (CPE) consisting of graphite powder obtained from a crushed pencil stick was herein modified with nanostructured TiO₂ (TiO₂@CPE) aiming for the detection of methyldopa in pharmaceutical samples. The TiO₂-modified graphite powder was characterized by scanning electron microscopy and X-ray diffraction, which demonstrated the oxide nanostructured morphology. Results evidenced that sensitivity was nonetheless increased due to electro-catalytic effects promoted by metal modification, and linear response obtained by differential pulse voltammetry for the determination of methyldopa (pH = 5.0) was between 10⁻180 μmol/L (Limit of Detection = 1 μmol/L) with the TiO₂@CPE sensor. Furthermore, the constructed sensor was successfully applied in the detection of methyldopa in pharmaceutical formulations and excipients promoted no interference, that indicates that the sensor herein developed is a cheap, reliable, and useful strategy to detect methyldopa in pharmaceutical samples, and may also be applicable in determinations of similar compounds.
甲基多巴是一种广泛用于治疗轻至中度高血压的儿茶酚胺，其在药物配方中的测定对于剂量精确性至关重要。因此，本文使用由碾碎铅笔芯获得的石墨粉制成的低成本碳糊电极（CPE），用纳米结构的TiO₂进行修饰（TiO₂@CPE），旨在检测药物样品中的甲基多巴。通过扫描电子显微镜和X射线衍射对TiO₂修饰的石墨粉进行了表征，证实了其氧化物纳米结构形态。结果表明，由于金属修饰促进的电催化作用，灵敏度仍然有所提高，使用TiO₂@CPE传感器通过差分脉冲伏安法测定甲基多巴（pH = 5.0）时获得的线性响应范围为10⁻180 μmol/L（检测限 = 1 μmol/L）。此外，构建的传感器成功应用于药物制剂中甲基多巴的检测，赋形剂未产生干扰，这表明本文开发的传感器是一种检测药物样品中甲基多巴的廉价、可靠且有用的策略，也可能适用于类似化合物的测定。
