Solvents
An interview with one of the most well-known emulsion specialists in Germany, the chemist, Dr J. Gernershausen, about solvents in equine care products.
What effect do the common solvents found in equine care products have on a horse’s skin?
Solvents speed up the transfer of the active ingredients into the deeper layers of the skin. This is often desirable for pharmaceuticals. Decidedly not, however, in the case of shampoo and a glossy coat, since these ingredients are expected to act as a means to remove dirt and as a protective coating for the hair on the surface. The solvents that act deep in the skin dry out the horse’s skin and this can result in concentrations in the animal’s body and, consequently, in illnesses. A transfer into deeper layers is only desirable in the case of hoof oil, although not through the use of solvents. The customary employment of solvents does expedite the transport of the active ingredients, but of course, it also hastens the "perils" of the solvents themselves.
Are essentially positive factors in products, such as, for example, tea tree oil or bay oil, reduced in terms of their impact or even obstructed by solvents?
Highly volatile solvents reduce these positive factors markedly. Through the rapid evaporation of the commonly employed solvents, certain quantities of active ingredients are, in the majority of cases, carried away and evaporate unused.
What kind of alternatives are there for solvents?
Water – via the indirect route of emulsions. Emulsions are compounds of oils and water with long-term stability that are stabilised through the application of so-called emulgents and emulsifying machines. This guarantees the shelf life of the products as well as their effect. Only mild, skin-friendly and above all raw materials not harmful to the health ought to be used. In the human area, this is standard.
Why are solvents still almost exclusively employed in equine care products?
Products containing solvents are easy and economical to produce. According to the motto, mix and done! Emulsions, on the other hand, require appreciably more production time, high investment costs in machinery as well as a very elaborate and often time-consuming formula development. Even so, however, the issue of equine health has still not completely been resolved.