Basavaiah Kanakapura, Somashekar Bankavadi Chikkaswamy, Ramakrishna Veeraiah
Department of Chemistry, University of Mysore, Manasagangotri, Mysore-570 006, India.
Acta Pharm. 2007 Mar;57(1):87-98. doi: 10.2478/v10007-007-0007-7.
One titrimetric and two spectrophotometric methods which are simple, sensitive and rapid are described for the assay of salbutamol sulphate (SBS) in bulk drug and in tablet dosage forms using N-bromosuccinimide (NBS) and two dyes, rhodamine-B and methylene blue, as reagents. In titrimetry, aqueous solution of salbutamol sulphate is treated with a measured excess of NBS in acetic acid medium and after the oxidation of SBS is complete, the unreacted oxidant is determined iodometrically. Spectrophotometric methods entail addition of a known excess of NBS in acid medium followed by the determination of residual oxidant by reacting with a fixed amount of either rhodamine B and measuring the absorbance at 555 nm (method A) or methylene blue and measuring the absorbance at 665 nm (method B). In all methods, the amount of NBS reacting corresponds to the amount of SBS content. Titrimetric method is applicable over 1.74 x 10(-4) - 8.68 x 10(-4) mol L(-1) range and the reaction stoichiometry is found to be 1:6 (SBS:NBS). In spectrophotometric methods, the absorbance is found to increase linearly with the concentration of SBS, which is corroborated by the correlation of coefficients of 0.9993 and 0.9988 for method A and method B, respectively. The systems obey Beer's law for 0.25-1.75 microg mL(-1) (method A) and 0.5-5.0 microg mL(-1) (method B). The calculated apparent molar absorptivity values were found to be 2.10 x 10(5) and 6.16 x 10(4) L mol(-1) cm(-1), for method A and method B, respectively. The limits of detection and quantification are also reported for both spectrophotometric methods. Intra-day and inter-day precision and accuracy for the developed methods were evaluated. The methods were successfully applied to the assay of SBS in tablet and capsule formulations and the results were statistically compared with those of a reference method. No interference was observed from common tablet adjuvants. The accuracy and reliability of the methods were further ascertained by recovery experiments via the standard-addition technique.
本文描述了一种滴定法和两种分光光度法，这些方法简单、灵敏且快速，用于测定原料药和片剂剂型中硫酸沙丁胺醇（SBS）的含量，使用N-溴代琥珀酰亚胺（NBS）以及两种染料罗丹明B和亚甲蓝作为试剂。在滴定法中，将硫酸沙丁胺醇的水溶液在乙酸介质中用计量过量的NBS处理，在SBS氧化完全后，用碘量法测定未反应的氧化剂。分光光度法包括在酸性介质中加入已知过量的NBS，然后通过与固定量的罗丹明B反应并在555nm处测量吸光度（方法A）或与亚甲蓝反应并在665nm处测量吸光度（方法B）来测定残留氧化剂。在所有方法中，与SBS反应的NBS量与SBS含量相对应。滴定法适用于1.74×10⁻⁴ - 8.68×10⁻⁴ mol L⁻¹范围，发现反应化学计量比为1:6（SBS:NBS）。在分光光度法中，发现吸光度随SBS浓度呈线性增加，方法A和方法B的相关系数分别为0.9993和0.9988，证实了这一点。该体系在0.25 - 1.75μg mL⁻¹（方法A）和0.5 - 5.0μg mL⁻¹（方法B）范围内符合比尔定律。方法A和方法B计算得到的表观摩尔吸光系数值分别为2.10×10⁵和6.16×10⁴ L mol⁻¹ cm⁻¹。还报告了两种分光光度法的检测限和定量限。评估了所开发方法的日内和日间精密度及准确度。这些方法成功应用于片剂和胶囊制剂中SBS的测定，并将结果与参考方法进行了统计学比较。未观察到常见片剂辅料的干扰。通过标准加入技术进行回收实验进一步确定了方法的准确性和可靠性。
