## 5 Discussion  
Concerning the European Regulation for cosmetic products and the European Directive for medicinal products, peloids are natural products with cosmetic or medicinal purposes, and in this context, they should be considered borderline products. However, the complexity of this concept and the boundary between regulations, and the prevalence of the principle of non-accumulation of regulations, determine as a key criterion the definition into which a product can fit. Considering the safety assessment of these products in accordance with Annex I of Regulation (EC) No. 1223/2009, the general toxicological profile of ingredients and the final product should be carried out. For establishing the rationale, based on the information collected and conclusions about product safety, the safety requirements should reflect the quantitative and qualitative composition of the raw materials, important for the establishment of the toxicological profile, their physicochemical characteristics, presence of impurities and trace elements and the risk of exposure to prohibited substances [58]. In addition, the microbiological quality and undesirable effects that could be found are important. Regarding the presentation of peloids as having therapeutic properties, they can be considered a medicinal product if they also have pathological significance. This is the condition for the case-by-case decision but still taking into account the characteristics of the peloid, its composition and pharmacological properties, and the risks which its use may entail. Experiments in vitro may support the understanding of the physiological mechanism by which application of mud cataplasms relieves pain in rheumatic patients or heal wounds. The medical hydrology clinical trials also offer scientific support for the medicinal significance of peloids, although the quality of evidence should be improved. It will be necessary to promote the evaluation of the long-term effects to support the therapeutic efficacy as well the specific biochemical effects that allow the distinction between therapeutic peloids. The transdermal drug delivery (TDD) research has had a significant technological \begin{table}
\begin{tabular}{c c c} \hline
**Inorganic Ion** & **Pathologies** & **References** \\ \hline Copper & Myctic infections & [49; 50] \\ Magnesium & Bursitis & [51] \\ Lithium & Gouty arthritis & [52] \\ Silver & Osteomyelitis, rheumatoid arthritis/antibacterial & [53] \\ Calcium & Dentinal hypersensitivity/osteoporosis & [54; 55] \\ Zinc & Wound healing/antiseptic & [56; 57] \\ \hline \end{tabular}
\end{table} 
Table 2: Inorganic ion in iontophoresis. evolution in the presentation of innovative solutions interrupting the skin barrier function (s.c.) and allowing the safe delivery of medicines [59]. Thermalism and physical medicine use specific methods in the rehabilitation, therapy, and prevention of numerous diseases, sometimes being the continuation of outpatient and hospital treatments for chronic diseases that require rehabilitation treatments. Balance therapy is quite common in the treatment of rheumatic and dermatological diseases. The mechanisms by which immersion in mineral or thermal water or the application of peloids relieves pain in rheumatic patients is not yet fully understood. Probably, the combination of factors such as mechanical, thermal, and chemical effects will be behind these benefits. According to the gate-control theory, pain relief can result from the pressure and temperature of the water or hot cataplasm on the skin. The heat stimulus can influence muscle tone and pain intensity, helping to reduce it, as well as muscle spasms. The importance of heat in the transport of essential elements of clays via pores, through their dilation followed by extreme sweating, is how the ionic transdermal delivery and therapeutic effect is predicted.