Pharmaceutical availability testing − can a drug-specific test be relevant for assessing the quality of dietary supplements?

Abstract

Our current novel analytical approach focuses on testing the quality of dietary supplements. Specifically, we examine the release of substances such as proline, tryptophan, tyrosine, carnitine, and vitamin C sourced from the EU, Switzerland, and the USA.In tablet-form supplements, release levels were low in both pharmacopoeial dissolution tests (Trp5 – 23%; Trp6 – 12%; VitC4 – 23%) and those simulating biorelevant conditions (Trp5 – 53%; Trp6 – 24%; VitC4 – 68%). The implementation of biorelevant conditions PhysioCell for capsule-form supplements led to an enhanced release of substances (from 11 to 106 percentage points) compared to pharmacopoeial dissolution tests. This indicates that the release of their active substance is strongly influenced by gastrointestinal motility, which, due to its high intra- and inter-individual variability, will result in inconsistent and unpredictable release and biological response.Thus, pharmacopeial methods serves as a reliable screening approach for the quality of dietary supplements.