Tolba M M, Salim M M, El-Awady M
Department of Pharmaceutical Analytical Chemistry, Faculty of Pharmacy, Mansoura University, Mansoura 35516, Egypt.
Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Horus University-Egypt, New Damietta 34518, Egypt.
R Soc Open Sci. 2021 Feb 3;8(2):201888. doi: 10.1098/rsos.201888.
In the present study, we conducted two facile and highly sensitive spectrofluorimetric approaches in order to quantify the vasoprotective agents; troxerutin (TROX) and calcium dobesilate (DOB) in the presence of hydroquinone (HQ) (as a highly toxic impurity and potential degradation product of DOB) in commercial formulations and human plasma. The first approach relies simply on using ethanol as an eco-friendly solvent for the estimation of DOB at 345 nm after being excited at 305 nm. The linearity was carefully investigated between DOB concentration and the relative fluorescence intensity in the range of 0.05-0.8 µg ml. Due to the high method simplicity and sensitivity, applying the first approach to quality control analysis and spiked human plasma samples with mean % recoveries 100.74 ± 3.71 adds another merit. The second approach involved rapid conventional fluorimetric estimation of ethanolic TROX solution in TROX/DOB combined dosage forms at 455/350 nm (emission/excitation) with a linear calibration chart covering the range of 0.1-1.2 µg ml. Moreover, the second approach involved a comprehensive study in a trial to solve the problem of superposition of DOB and HQ graph adopting the first derivative synchronous fluorimetric mechanism in ethanol at Δ = 60 nm. Therefore, DOB was measured at 286 and 323 nm, while HQ could be quantitated at 301 nm. The Beer-Lambert Law has complied over the ranges of 0.1-1.0 and 0.02-0.4 µg ml for DOB and HQ, respectively. Guidelines adopted by the International Council of Harmonization (ICH) were used to validate the target approaches. The developed methods are more convenient for routine quality control laboratory instead of the time-consuming and sophisticated reported techniques. Moreover, different aspects of evaluating the greenness of the proposed approaches were conducted to have a complete image of their environmental impact.
在本研究中，我们开展了两种简便且高度灵敏的荧光光谱法，以定量测定商业制剂和人血浆中存在对苯二酚（HQ）（作为一种剧毒杂质和多贝斯钙（DOB）的潜在降解产物）时的血管保护剂；曲克芦丁（TROX）和多贝斯钙（DOB）。第一种方法仅依靠使用乙醇作为环保型溶剂，在305 nm激发后于345 nm处测定DOB。仔细研究了DOB浓度与0.05 - 0.8 µg/ml范围内相对荧光强度之间的线性关系。由于该方法具有高度的简便性和灵敏性，将第一种方法应用于质量控制分析以及加标人血浆样品，平均回收率为100.74 ± 3.71%，这增添了另一项优点。第二种方法涉及在455/350 nm（发射/激发）处对TROX/DOB复方制剂中的乙醇TROX溶液进行快速常规荧光测定，线性校准曲线涵盖0.1 - 1.2 µg/ml范围。此外，第二种方法涉及一项全面研究，试图采用乙醇中Δ = 60 nm的一阶导数同步荧光机制来解决DOB和HQ图谱叠加的问题。因此，在286和323 nm处测定DOB，而在301 nm处可定量测定HQ。比尔-朗伯定律分别在0.1 - 1.0 µg/ml和0.02 - 0.4 µg/ml范围内适用于DOB和HQ。采用国际协调理事会（ICH）通过的指南对目标方法进行验证。所开发的方法对于常规质量控制实验室而言比耗时且复杂的已报道技术更为便捷。此外，还对所提出方法的绿色度的不同方面进行了评估，以全面了解其对环境的影响。
