Tubino Matthieu, De Souza Rafael L
State University of Campinas, Institute of Chemistry, CP 6154, 13083-970 Campinas, São Paulo, Brazil.
J AOAC Int. 2005 Nov-Dec;88(6):1684-7.
A gravimetric method for the determination of diclofenac in pharmaceutical preparations was developed. Diclofenac is precipitated from aqueous solution with copper(II) acetate in pH 5.3 (acetic acid/acetate buffer). Sample aliquots had approximately the same quantity of the drug content in tablets (50 mg) or in ampules (75 mg). The observed standard deviation was about +/- 2 mg; therefore, the relative standard deviation (RSD) was approximately 4% for tablet and 3% for ampule preparations. The results were compared with those obtained with the liquid chromatography method recommended in the United States Pharmacopoeia using the statistical Student's t-test. Complete agreement was observed. It is possible to obtain more precise results using higher aliquots, for example 200 mg, in which case the RSD falls to 1%. This gravimetric method, contrary to what is expected for this kind of procedure, is relatively fast and simple to perform. The main advantage is the absolute character of the gravimetric analysis.
开发了一种用于测定药物制剂中双氯芬酸的重量法。双氯芬酸在pH 5.3（乙酸/乙酸盐缓冲液）中用乙酸铜从水溶液中沉淀出来。片剂（50毫克）或安瓿剂（75毫克）中的样品等分试样具有大致相同数量的药物含量。观察到的标准偏差约为±2毫克；因此，片剂的相对标准偏差（RSD）约为4%，安瓿剂制剂的相对标准偏差约为3%。使用统计学生t检验将结果与美国药典推荐的液相色谱法获得的结果进行比较。观察到完全一致。使用更高的等分试样（例如200毫克）可以获得更精确的结果，在这种情况下，RSD降至1%。与这种方法预期的情况相反，这种重量法相对快速且易于操作。主要优点是重量分析的绝对特性。
