Finished Testing of Homeopathic Products: A Retrospective Review of Thinking

By Mark Land, M.S., RAC-US, AAHP President 

In this issue we offer a series of evergreen of articles on finished product testing—a topic of constant focus. We chose to refresh your knowledge these four articles to sage readers or introduce the articles to newer readers because these four are as relevant today as when published 12–15 years ago. While much has remained the same in control strategies of homeopathic manufacturers since the articles were first published, this column highlights what has changed.  

1. “Finished Product Testing” by Mary Beth Watkins highlights the importance of Quality By Design (QbD) as a fundamental tenant of any quality strategy. QbD stresses building quality into each step of the drug manufacturing process from sourcing raw materials to finished product testing and stability testing. This approach remains the standard today in manufacturing homeopathic medicines as when Mary Beth wrote about it. 

QbD demands specifications for raw materials, intermediate, and final products. Finished product testing confirms that the QBD quality strategy has been successful and delivered a finished product of appropriate quality, strength, and purity. In Mary Beth’s article she noted the lack of finished product specifications in the Homeopathic Pharmacopoeia of the United States (HPUS) and the United States Pharmacopoeia (USP). While that was true then it is not the case now. The HPUS released a white paper for public comment on finished product testing about 18 months ago. The USP contains a rich set of testing strategies by dosage form. 

2. In “Overview of 3 Plant Contaminants,” there are updates for all three plant contaminants. For bromide contamination associated with methyl bromide fumigation of the botanical material directly or fumigation of wooden pallets used to store botanical materials, this was a novel concern at the time. Today fumigation with methyl bromide has been greatly reduced but manufacturers should include bromide contamination on audits and risk analyses of suppliers. 

This article also examines aflatoxin contamination of fresh botanical material. It notes that it is more challenging in certain growing conditions than others. The HPUS, along with extensive information on Good Cultivation Practices, provides parameters to use in an aflatoxin risk analysis.  

Last examined in the article is heavy metal contamination in tinctures. At that time AAHP member Schwabe (DHU) published results demonstrating that the homeopathic tincture manufacturing process greatly reduces heavy metal contamination from botanical sources. While this was comforting news then, in today’s environment appropriate qualification of botanicals suppliers to the homeopathic manufacturing site along with adequate risk analysis is the best approach to managing elemental impurities.  

3. “Assays of Homeopathic Preparations” discusses work by Dr. Michael Keusgen, a professor who dismisses the need for assays of homeopathic medicines on clinical grounds. The article’s author notes that in Keusgen’s paper, “chemically defined substances usually have a dose-response curve that defines efficacy, and thus assays are required for both quality and safety reasons. However, Professor Keusgen goes on to state that homeopathic products are not subject to dose-response curves in which the concentration of the starting material is related to the efficacy of the product. Therefore, physico-chemical assays are, by and large, not meaningful for these medicines.” 

Let’s bring this into a modern interpretation. From a quality standpoint, specifications and testing against those specifications is fundamental to reproducibility and safety. While Dr. Keusgen was likely speaking of highly dilute homeopathic substances in his discussion of the dose response curve, not all homeopathic drug products are highly dilute. Dose response curve may apply therapeutically and from a safety standpoint. Therefore, an assay when possible may be appropriate.  

All of these updates above have been noted within these articles. Enjoy this retrospective and the light it shines on how finished product testing of homeopathic drug products has evolved in the most recent decade, but for the most how much has remained the same in control strategies.