UV spectroscopy of tramadol (TRA) and paracetamol (PAR) shows substantial spectral overlap, which is a challenge for their simultaneous determination without preliminary separation. Three smart spectrophotometric methods based on the ratio spectra developed from the overlapping UV spectra of their binary mixture can be applied for a quantitative estimation of both drugs. The first derivative (DR¹) of the ratio spectra was computed, and then the amplitudes were measured at 268.7 and 237.4 nm for TRA and PAR, respectively. The mean centered ratio (MCR) of the spectra was estimated by measuring the MCR spectra at 279 and 241.5 nm for TRA and PAR, respectively. Finally, the dual wavelength (DW) method was applied by measuring the difference in absorbance at 224.1 and 268.5 nm for TRA determination and at 248 and 285.4 nm for PAR determination without any interference. All the above-mentioned spectrophotometric methods can be used to estimate TRA in the linear range of 10–110 μg/mL. Furthermore, PAR can be estimated in the linear range of 1–25 μg/mL. These methods were successfully applied to the analysis of the combined dosage form and bulk powder of TRA and PAR. The methods were validated according to the International Conference on Harmonization (ICH) guidelines, and the obtained results were statistically compared with those obtained by previously reported methods. No significant difference with respect to accuracy and precision was observed.

曲马多 (TRA) 和扑热息痛 (PAR) 的紫外光谱显示出大量的光谱重叠，这对它们在没有初步分离的情况下同时测定是一个挑战。三种基于比率光谱的智能分光光度法方法是从其二元混合物的重叠紫外光谱发展而来的，可用于对两种药物进行定量估计。一阶导数（DR ¹) 的比率光谱，然后分别在 268.7 和 237.4 nm 处测量 TRA 和 PAR 的幅度。光谱的平均中心比 (MCR) 分别通过测量 TRA 和 PAR 在 279 和 241.5 nm 处的 MCR 光谱来估计。最后，通过测量 224.1 和 268.5 nm 处的吸光度差异来应用双波长 (DW) 方法进行 TRA 测定，以及 248 和 285.4 nm 处的吸光度差异用于 PAR 测定，没有任何干扰。所有上述分光光度法都可用于估计 TRA 在 10-110 μg/mL 的线性范围内。此外，可以在 1–25 μg/mL 的线性范围内估算 PAR。这些方法已成功应用于 TRA 和 PAR 的组合剂型和散装粉末的分析。这些方法根据国际协调会议 (ICH) 指南进行了验证，并将获得的结果与以前报告的方法获得的结果进行了统计比较。未观察到准确度和精密度方面的显着差异。