Safety Assessment of the Trace Element Impurities Ni and Cr in Pharmaceutical Herbal Products for Teething from Polish Pharmacies

Control of elemental impurities (EIs) in pharmaceutical herbal products is currently important but not a very popular topic in modern toxicological analysis. The occurrence and concentration of EIs in the pharmaceutical herbal products should be controlled and meet the standards of directive International Conference on Harmonisation’s Q3D Guideline on Elemental Impurities. An interesting area of interest is measuring EIs including toxic and allergic metals in pharmaceutical herbal products for teething. The aim of this article was determination of Ni and Cr impurities in pharmaceutical herbal products for teething available in Polish pharmacies. Justifications were (1) herbs as an important source of EIs and (2) infants may be particularly sensitive to the toxic effects of metals because they tend to absorb a higher fraction of an oral dose. The analysis was carried out using microwave-assisted wet digestion with concentrated nitric acid and electrothermal atomisation atomic absorption spectrometry. The safety assessment involved a triple approach: (1) level of Ni and Cr impurities in pharmaceutical samples; (2) level of Ni and Cr impurities including one-time administration of teething gels and (3) daily intake of metals. In all three cases, the results indicate that the standards of directive ICH Q3D are met for Ni and Cr. Overall, it can be concluded that none of the teething gels represents a health hazard to infants.