El-Ries Mohamed A, Mohamed Gehad, Khalil Shaeban, El-Shall Manal
National Organization for Drug Control and Research, Egypt.
Chem Pharm Bull (Tokyo). 2003 Jan;51(1):6-10. doi: 10.1248/cpb.51.6.
Two simple and accurate methods are described for the determination of piroxicam and tenoxicam in their pharmaceutical preparations. The spectrophotometric method involves the oxidation of these drugs with potassium iodate in acid medium with the liberation of iodine and subsequent extraction with cyclohexane followed by measuring the absorbance at lambda=522 nm. Beer's law is obeyed in the concentration range of 0.05-1.1 and 0.05-0.6 mg x ml(-1) for piroxicam and tenoxicam, respectively. The apparent molar absorptivities of the resulting coloured products are found to be 2.7 x 10(3) and 2.5 x 10(3) l mol(-1) x cm(-1), whereas Sandell sensitivities are 0.012 and 0.013 g x cm(-2) for piroxicam and tenoxicam, respectively. The potentiometric method involves the direct titration of both drugs with N-bromosuccinimide in acid medium and the end point is determined potentiometrically using platinum indicator electrode. Piroxicam and tenoxicam can be determined quantitatively in the concentration range of 0.33-3.37 and 0.33-4.08 mg x ml(-1) for tenoxicam and piroxicam, respectively. The standard deviation and relative standard deviation values are found to be ranged from 0.05-0.07 and 0.37-0.98% and 0.025-0.078 and 0.25-1.2% for tenoxicam and piroxicam, respectively. The two methods are accurate within +/-1.0%. Optimum conditions affecting both methods are studied. The proposed methods are applied for the determination of the drugs in pure form and in commercial pharmaceutical preparations.
本文描述了两种简单且准确的方法，用于测定药物制剂中的吡罗昔康和替诺昔康。分光光度法是在酸性介质中用碘酸钾氧化这些药物，释放出碘，随后用环己烷萃取，然后在λ = 522 nm处测量吸光度。吡罗昔康和替诺昔康在浓度范围分别为0.05 - 1.1和0.05 - 0.6 mg·ml⁻¹时遵循比尔定律。所得有色产物的表观摩尔吸光系数分别为2.7×10³和2.5×10³ l·mol⁻¹·cm⁻¹，而桑德尔灵敏度对于吡罗昔康和替诺昔康分别为0.012和0.013 g·cm⁻²。电位滴定法是在酸性介质中用N - 溴代琥珀酰亚胺直接滴定这两种药物，使用铂指示电极通过电位法确定终点。替诺昔康和吡罗昔康分别在浓度范围为0.33 - 3.37和0.33 - 4.08 mg·ml⁻¹时可进行定量测定。替诺昔康和吡罗昔康的标准偏差和相对标准偏差值分别为0.05 - 0.07和0.37 - 0.98%以及0.025 - 0.078和0.25 - 1.2%。这两种方法的准确度在±1.0%以内。研究了影响这两种方法的最佳条件。所提出的方法应用于测定纯品形式和市售药物制剂中的药物。
