Kressmann S, Müller W E, Blume H H
Biocenter Niederursel, Department of Pharmacology, University of Frankfurt, Germany.
J Pharm Pharmacol. 2002 May;54(5):661-9. doi: 10.1211/0022357021778970.
Ginkgo biloba-containing brands are one of the top sellers within the growing market for herbal remedies in many European countries as well as in the USA. In the consumers' interest, these brands should feature a certain quality and should be transparent in quality claims. In this investigation, a variety of products on the USA market was studied with respect to pharmaceutical quality, such as quantity of constituents and in-vitro dissolution. In terms of the content of active substances, flavone glycosides ranged from 24% to 36% and terpene lactones from 4% to 11%. With ginkgolic acids, there was a very large range, from < 500 ppm to about 90000 ppm. Comparing the dissolution rates of terpene lactones and flavone glycosides within the single products, most were approximately the same. Thus, terpene lactones and flavone glycosides were released from these products and dissolved at the same rate in most cases. Furthermore, most of the products investigated released more than the required 75% of the content of both components within 30 min. However, several products showed clear and relevant differences in dissolution rates to the rest (e.g. < 75% within 30 min or even less than 25% after 60 min in one case, indicating much poorer pharmaceutical quality). Beside the comparability respectively standardisation of the extracts used, the in-vitro dissolution of the relevant constituents should be similar to other drugs to guarantee comparable in-vivo performance of herbal products. An important step in standardising pharmaceutical quality is the pharmacopoeial monograph for Ginkgo biloba extract in Germany, standardising the content of pharmacologically relevant substances (flavone glycosides 22-27% and terpenlactones 5-7%, 2.8-3.4% ginkgolides A, B, C and 2.6-3.2% bilobalide thereof). Many of the investigated products, which refer to the German Commission E (of the Federal Institute for Drugs and Medicinal Devices) monograph, are not in accordance with this specification. Thus, they can not be considered to be pharmaceutically equivalent.
在许多欧洲国家以及美国，含银杏叶的品牌产品是不断增长的草药市场上的畅销品之一。为了消费者的利益，这些品牌产品应具备一定质量，且质量声明应透明。在本次调查中，对美国市场上的多种产品进行了药物质量方面的研究，如成分含量和体外溶出度。就活性物质含量而言，黄酮苷的含量在24%至36%之间，萜类内酯的含量在4%至11%之间。银杏酸的含量范围非常大，从小于500 ppm到约90000 ppm。比较单一产品中萜类内酯和黄酮苷的溶出率，大多数大致相同。因此，在大多数情况下，萜类内酯和黄酮苷从这些产品中释放并以相同速率溶解。此外，大多数被调查产品在30分钟内释放的两种成分含量超过了规定的75%。然而，有几种产品与其他产品相比，溶出率存在明显且显著的差异（例如，30分钟内低于75%，在一种情况下60分钟后甚至低于25%，表明其药物质量差得多）。除了所使用提取物的可比性或标准化之外，相关成分的体外溶出度应与其他药物相似，以确保草药产品具有可比的体内性能。德国对银杏叶提取物的药典专论是标准化药物质量的重要一步，它对药理相关物质的含量进行了标准化（黄酮苷22 - 27%，萜类内酯5 - 7%，其中银杏内酯A,B,C为2.8 - 3.4%，白果内酯为2.6 - 3.2%）。许多参考德国联邦药物和医疗器械研究所委员会E专论的被调查产品并不符合该规范。因此，它们不能被认为在药学上是等效的。
