Abstract In the present work, a simple approach for colorimetric determination of allopurinol and its major metabolite oxypurinol is presented using gold nanoparticles as a probe. Gold nanoparticles were synthesized using the citrate reduction method and then functionalized using melamine (mel-AuNPs). The nanoparticles were characterized using UV–vis spectrophotometry, dynamic light scattering and transmission electron microscopy. The bare AuNPs capped with citrate anions (cit-AuNPs) gave a linear response towards allopurinol and oxypurinol within the range 0.20–40.0 μM and 0.25–25.0 μM respectively; however the melamine functionality on the AuNPs exhibited specific response for oxypurinol from 0.10 to 15.0 μM. This enabled development of a simple approach for the quantitation of the metabolite using mel-AuNPs, while the quantitation of allopurinol was carried out using the regression parameters of cit-AuNPs and the calculated amount of metabolite. For method optimization parameters such as the pH, incubation time and effect of ionic strength of the medium which can cause aggregation of nanoparticles were studied. The methodology was found to yield reliable results as evident from the validation results. The application of the method is demonstrated by analyzing allopurinol from tablet formulations and the drug and its metabolite from spiked plasma samples.

中文翻译：

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柠檬酸盐/三聚氰胺功能化金纳米粒子，用于同时测定血浆和药物中的别嘌呤醇及其主要代谢物羟嘌呤醇

摘要 在目前的工作中，提出了一种使用金纳米粒子作为探针比色测定别嘌呤醇及其主要代谢物氧嘌呤醇的简单方法。使用柠檬酸盐还原法合成金纳米粒子，然后使用三聚氰胺（mel-AuNPs）进行功能化。使用紫外-可见分光光度法、动态光散射和透射电子显微镜对纳米颗粒进行表征。用柠檬酸根阴离子（cit-AuNPs）覆盖的裸金纳米粒子对别嘌呤醇和羟嘌呤醇分别在 0.20-40.0 μM 和 0.25-25.0 μM 范围内给出线性响应；然而，AuNP 上的三聚氰胺官能团对 0.10 至 15.0 μM 的氧嘌呤醇表现出特定响应。这使得开发了一种使用 mel-AuNP 对代谢物进行定量的简单方法，而别嘌呤醇的定量是使用cit-AuNPs的回归参数和计算出的代谢物量进行的。对于方法优化参数，如 pH 值、孵育时间和可能导致纳米颗粒聚集的介质离子强度的影响进行了研究。从验证结果可以明显看出，该方法产生了可靠的结果。通过分析片剂配方中的别嘌呤醇和加标血浆样品中的药物及其代谢物，证明了该方法的应用。从验证结果可以明显看出，该方法产生了可靠的结果。通过分析片剂配方中的别嘌呤醇和加标血浆样品中的药物及其代谢物，证明了该方法的应用。从验证结果可以明显看出，该方法产生了可靠的结果。通过分析片剂配方中的别嘌呤醇和加标血浆样品中的药物及其代谢物，证明了该方法的应用。