Disinfection – what does it mean?

To be suitable as an active ingredient for disinfection, a substance must reduce the number of pathogens in a defined time period to such an extent that the remaining germs can no longer cause disease. The required treatment time is typically defined as the time required to inactivate 99,999% of the germs. If disinfectants are to be applied to the skin, they must be as body-tissue-compatible as possible. Surface disinfectants must not damage sensitive surfaces. Disinfectants must not cause serious side effects if they happen to enter the organism through open wounds or via absorption through the skin. Care of the skin using hand lotion is important in this context as, over time, the use of disinfectants dries out the skin, making it more sensitive and more susceptible to infection. Since the substances ultimately end up in the environment after use, environmental compatibility is also an important criterion.

Evonik is one of the leading manufacturers of hydrogen peroxide and peracetic acid and other selected biocidal active ingredients such as N-Alkyl aminopropyl glycine (trade name REWOCID® WK 30). These substances are what make the disinfectants work.

Strong oxidants such as hydrogen peroxide (H2O2) or peracetic acid (PAA) are frequently used for disinfection of surfaces or treatment of wastewater. Viruses, bacteria and, other microbes are killed by unspecific action mechanisms. The peroxides penetrate the cell envelope of microorganisms and change it so that it loses its barrier function. PAA in particular has proved to be a potent disinfectant. Due to its structure, it can very easily penetrate the cell membrane. PAA causes irreversible damage to the genome of bacteria and viruses. No resistance mechanisms against PAA have been discovered to date. And peroxides are an environmentally safe way of disinfecting as they decompose into water, oxygen and in case of PAA – acetic acid.

Evonik provides various hydrogen peroxide and peracetic acid products for use as biocides. They are, among others, used for disinfection of spaces and surfaces. Hydrogen peroxide can also be used to disinfect wounds.

Peroxides also help in the fight against Coronavirus: PERACLEAN® 15 has been approved by the US Environmental Protection Agency to be used as an active ingredient in disinfectants against Sars-CoV-2. That is the virus that causes Covid-19.

PERACLEAN® 15 has demonstrated effectiveness against viruses similar to SARS-COV-2 on hard non-porous surfaces. Therefore, it can be used against SARS-COV-2 when used in accordance with the directions for use.

The active ingredient N-Alkyl aminopropyl glycine is part of the group of amphoteric surfactants. These molecules are particularly adept at attaching themselves to the membranes of bacteria where they then cause irreversible structural damage so that the membranes lose their barrier properties. Surfactants also remove the lipids from the envelope of enveloped viruses, and in this way, they inactivate the pathogens. REWOCID® WK 30 from Evonik combines both cleansing and biocidal properties. Disinfectant cleaners with this biocide are primarily used to treat hard surfaces.

Chlorhexidine is an antiseptic ingredient that is particularly effective against bacteria. The effects of the chlorinated biguanide derivative are based on a disruption of the function of the cell membrane. In higher concentrations, it has a bactericidal effect through structural damage to the membrane. In lower concentrations, it leads to the loss of small molecules and to the precipitation of cytoplasmic proteins, which has a bacteriostatic effect. Chlorhexidine-based soap is frequently used in the USA for hygienic hand disinfection and it is the classic ingredient in mouthwashes and oral rinses. Chlorhexidine is included in the WHO list of essential medicines.

Alcoholic solutions are also widely used in hand sanitizers. The monovalent, short-chain alcohols that they contain react non-specifically with bacterial proteins. Enveloped viruses are addressed by all alcohols, to a greater or lesser extent depending on their concentration. However, ethanol (2 carbon atoms) is more effective than propanol (3 carbon atoms) against non-enveloped viruses. The alcohols remove lipids from the virus envelope and thus inactivate the pathogens. In general, the effectiveness of alcohols increases with increasing chain length (up to 8 carbon atoms), however, in inverse proportion to their tolerance. For this reason, alcohols with more than 4 carbon atoms are not normally used as an ingredient in hand sanitizers.