Mecetronium Etilsulfate (MES)

Chemical structure
Mecetronium Etilsulfate (MES) is an organic salt, which belongs to the class of the quaternary ammonium compounds (QAC). The chemical name is ethyl hexadecyl dimethyl ammonium ethyl sulfate. Quaternary ammonium compounds are synthesized by the reaction of tertiary amines with alkylating agents, e.g. diethyl sulfate.

Chemical structure of Mecetronium Etilsulfate (MES):

Characteristics
Mecetronium etilsulfate as pure substance is a white crystalline powder with a sweetish smell. MES is very hygroscopic and normally used as 30% aqueous solution, which is almost color- and virtually odorless. MES possesses good water solubility, but is also well soluble in ethanol, propanol and acetone. Due to its structure with a long hydrophobic alkyl moiety and the ionic (saline) hydrophilic molecule field, MES is a surfactant.

Effect mechanisms
MES is a so-called membrane-active agent and does not differ from other quaternary ammonium compounds in terms of mode of action and effect mechanism. MES unfolds its activity on the outer cell membrane as well as on the inner cytoplasm membrane. MES destroys the outer cell membrane at least of gram-negative bacteria and thus accelerates the own absorption. In the first step, MES is absorbed and then it penetrates the outer cell membrane. Here, MES reacts with several components, e.g. lipids and proteins, and produces a disorientation of the membrane. Low-molecular-weight parts inside the cell can escape. Further on, proteins and nucleic acid are degraded. Finally, this results in a lysis of the cell wall.
So far there are no reports in the literature, which indicate that there are microorganisms developing resistances against MES.

Fields of application
Due to its structure with a hydrophobic alkyl moiety, MES belongs to the quaternary ammonium compounds, which possess a biocidal efficacy. In addition, MES does not contain a halogen atom (e.g. chlorine) in the molecule, neither as substituent nor as counterion. Thus it has a better skin and material compatibility than for instance benzalkonium chloride.
For more than 35 years already, the pharmaceutical raw material MES has been in use as active ingredient in Sterillium®.