Croom Edward, Pace Roberto, Paletti Andrea, Sardone Nicola, Gray Dean
University of Mississippi, School of Pharmacy, Adjunct Associate Professor of Pharmacognosy, University, MS 38655, USA.
J AOAC Int. 2007 May-Jun;90(3):647-58.
A single-laboratory validation was completed for a method to determine total terpene lactones in Ginkgo biloba products. The method determines terpene lactones on the basis of the main terpene lactones (Bilobalide, Ginkgolide A, Ginkgolide B, Ginkgolide C, and Ginkgolide J) by high-performance liquid chromatography with evaporative light-scattering detection after extraction. Nine matrixes were chosen for study, including crude leaf material, standardized dry powder extract, single- and multiple-entity finished products, and alcohol and glycerin tinctures. The sample purification with prepacked columns allows selective extraction of the terpene lactones with no interferences from any matrix under study. A Youden ruggedness trial testing 7 instrumental and preparation factors with the potential to affect quantitative results showed that 2 factors (volume of the column elution solvent and pH of the diluent) were the most important parameters to control during sample preparation. The method performed well in terms of precision; 4 matrixes tested in triplicate over a 3-day period showed an overall repeatability relative standard deviation (RSD) of about 3%. HorRat values were within the limits for performance acceptability, ranging from 0.5 to 1.0. Analysis of variance testing at a = 0.05 showed no significant differences among the within-or between-group sources of variation, although comparison of within-day, between-day, and total precision showed that most of the RSD came from within-day determinations except those for the Ginkgo dry extract (Gb-SLV-2). Accuracy testing at 4 concentration levels of terpene lactones obtained by spiking a negative control matrix at approximately 300, 750, 1500, and 2250 microg/mL gave recoveries of about 91% for the 300 microg/mL level, about 98% for the 750 microg/mL level, about 99% for the 1500 microg/mL level, and 97% for the 2250 microg/mL level with an overall recovery of 96% and an RSD of 3.2%.
完成了一种测定银杏制品中总萜内酯方法的单实验室验证。该方法通过高效液相色谱法结合蒸发光散射检测，在提取后基于主要萜内酯（白果内酯、银杏内酯A、银杏内酯B、银杏内酯C和银杏内酯J）来测定萜内酯。选择了九种基质进行研究，包括粗叶原料、标准化干粉提取物、单成分和多成分成品以及酒精和甘油酊剂。使用预装柱进行样品净化可选择性提取萜内酯，不受所研究的任何基质干扰。一项尤登稳健性试验测试了7个可能影响定量结果的仪器和制备因素，结果表明2个因素（柱洗脱溶剂体积和稀释剂pH值）是样品制备过程中最重要的控制参数。该方法在精密度方面表现良好；在3天内对4种基质进行一式三份测试，总体重复性相对标准偏差（RSD）约为3%。HorRat值在性能可接受范围内，范围为0.5至1.0。在α = 0.05水平进行方差分析测试表明，组内和组间变异来源之间无显著差异，尽管日内、日间和总精密度比较表明，除银杏干提取物（Gb-SLV-2）外，大多数RSD来自日内测定。通过向阴性对照基质中添加萜内酯，使其浓度分别约为300、750、1500和2250μg/mL，在4个浓度水平进行准确度测试，结果表明，300μg/mL水平的回收率约为91%，750μg/mL水平约为98%，1500μg/mL水平约为99%，2250μg/mL水平约为97%，总体回收率为96%，RSD为3.2%。
