Bakry R S, Razak O A, el Walily A F, Belal S F
Pharmaceutical Analytical Chemistry Department, College of Pharmacy, University of Alexandria, Egypt.
J Pharm Biomed Anal. 1998 May;17(1):95-101. doi: 10.1016/s0731-7085(97)00172-6.
A simple spectrophotometric method for the determination of timonacic is presented. The procedure is based on the chelate formation with palladium(II) chloride in buffered medium. The optimum conditions for the complex formation were ascertained and the method was developed for the determination of timonacic in the concentration range of 28-48 micrograms ml-1. The emperical formula of the formed complex was determined, by applying different spectrophotometric methods, at optimum pH of 4.8 and an ionic strength of mu = 0.5. The stoichiometric ratio was found to be 2:1 (timonacic/palladium) as calculated by the mole ratio, continuous variations and Asmus methods. The continuous variations and Nash methods were applied for the determination of the conditional stability constant of the formed yellow-water soluble complex and was found to be 3.27 x 10(7). The proposed methods was found to be suitable for the determination of timonacic in bulk and in its pharmaceutical tablets.
本文介绍了一种测定替莫那昔的简单分光光度法。该方法基于在缓冲介质中与氯化钯（II）形成螯合物。确定了络合物形成的最佳条件，并建立了用于测定浓度范围为28 - 48微克/毫升的替莫那昔的方法。通过应用不同的分光光度法，在最佳pH值为4.8和离子强度μ = 0.5的条件下，确定了形成的络合物的经验式。通过摩尔比、连续变化法和阿斯穆斯法计算，化学计量比为2:1（替莫那昔/钯）。应用连续变化法和纳什法测定形成的黄色水溶性络合物的条件稳定常数，发现其为3.27×10⁷。所提出的方法适用于测定原料药和其药物片剂中的替莫那昔。
