Tolfenamic acid (TA) is commonly used in humans and animals because of its anti‐inflammatory, antipyretic, and analgesic effects. So far, no study has been carried out to develop a validated spectrofluorimetric method for determination of TA. Therefore, the present study aimed to develop and validate a simple, accurate, rapid, economical, and precise spectrofluorimetric method to assay TA in its pure and dosage forms, and also in degraded solutions. The fluorimetric method had higher sensitivity compared with the spectrophotometric and high‐performance liquid chromatography methods and could determine the drug at the microgram level. Optimum pH of TA for maximum fluorescence intensity was 3, and its two pK_a values were calculated as 1.95 and 4.05. The proposed method was validated according to the guidelines of the International Council for Harmonisation, and parameters such as linearity, range, accuracy, precision, sensitivity, robustness, specificity, and solution stability were tested. Stress‐induced degradation studies on TA did not affect the accuracy and precision of the proposed method. The results obtained indicated that the method was linear over the concentration range 0.2–0.9 × 10⁻³ M with good accuracy, precision, and robustness for assay of TA in its pure and its tablet dosage forms and was comparable statistically with the British Pharmacopoeia method.

中文翻译：

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开发和验证用于分析纯片剂和片剂剂型中的甲苯磺酸的分光光度法。

甲苯酚酸（TA）具有抗炎，解热和镇痛作用，常用于人类和动物。到目前为止，还没有进行任何研究来开发一种经过验证的分光光度法测定TA的方法。因此，本研究旨在开发和验证一种简单，准确，快速，经济，精确的荧光分光光度法，以纯，剂型以及降解溶液的形式测定TA。与分光光度法和高效液相色谱法相比，荧光法具有更高的灵敏度，并且可以在微克水平上测定药物。最大荧光强度的TA的最佳pH为3，其两个p K _a值计算为1.95和4.05。根据国际协调理事会的指南对提出的方法进行了验证，并测试了线性，范围，准确性，精密度，灵敏度，鲁棒性，特异性和溶液稳定性等参数。应力诱发的TA降解研究并未影响所提出方法的准确性和精确性。所得结果表明，该方法在0.2–0.9×10 ^-3 M的浓度范围内呈线性，对纯及其片剂剂型TA的测定具有良好的准确性，精密度和耐用性，并且与英国药典方法具有统计学可比性。