A virucidal agent against naked vires containing at least 70% of methanol and/or ethanol and from 1 to 10% of glycerol and optionally, up of 5% of castor oil for improving the skin compatibility.

The present invention relates to a virucidal agent against naked viruses 
which include, inter alia, polio virus 1, ECHO virus 11, ECHO virus 12, 
rota virus, reo virus 3 and adeno virus 2. 
BACKGROUND OF THE INVENTION 
It is known that viruses having a lipoid sheath are relatively sensitive 
and, thus, can be deactivated or even killed by the action of virucidal 
disinfectants known to date. A problem arises in combatting the naked 
viruses that are essentially more resistant to conventional disinfectants 
and, so far, could actually be killed only by applying formaldehyde at a 
relatively high concentration. However, formaldehyde is undesirable for 
toxicological reasons and is not applicable as a disinfectant for parts of 
the body either in laboratory tests or in clinical use. 
The prior art literature on disinfecting or deactivating activities, 
respectively, of commercially available and skin-compatible disinfectants 
is contradictory. However, investigations conducted by the present 
inventors have resulted in the finding that most of the skin-compatible 
disinfectants are virtually ineffective against naked viruses. What has 
been reported on the effects of alcohols is also contradictory. 
Investigations conducted by the present inventors on the efficacy of 
isopropanol against naked vires showed that this alcohol is only very 
weakly active or ineffective against nakes viruses. These investigations 
further resulted in the finding that in a surprising manner ethanol and 
methanol are highly active and lose their activity only if they contain 
more than 30% of water. Thus, while ethanol acts as a disinfecting or 
deactivating agent, respectively, against bacteria and fungi even at a 
substantially lower concentration, the water content of the alcohols must 
be substantially reduced in order to accomplish a successful control or 
deactivation of nakes viruses. 
As all alcohols, when applied to the skin, have an undesired effect of 
removing fat therefrom and rendering the skin brittle and chapped, it was 
a matter of choice to add skin-protecting agents to the alcohols such as 
to effect a restitution of the natural skin fat level. By corresponding 
investigations it has been found that, surprisingly, an addition of from 1 
to 10% of glycerol to methanol and ethanol does not adversely affect the 
efficacy of these alcohols. It has further been found that additive 
amounts of up to 5% of castor oil also do not deteriorate the activity 
against naked viruses while the castor oil contributes to improve the skin 
compatibility. 
SUMMARY OF THE INVENTION 
The present invention relates to virucidal agents against naked viruses, 
which agents consist of at least 70% of methanol and/or ethanol and from 1 
to 10% of glycerol. It is preferred that castor oil, in an amount of up to 
5%, is further added to said virucides. 
The present invention also relates to a method of disinfecting or 
deactivating naked vires by use of the aforementioned virucidal agents. 
DETAILED DESCRIPTION OF THE INVENTION 
Since the activity of the virucidal agents of the present invention rapidly 
decreases at an alcohol concentraton of less than 70%, the virucidal 
agents according to the present contain up to 97%, and preferably 80 to 
90%, of methanol and/or ethanol. The amount of glycerol preferably is from 
1 to 5%, and the additive amount of castor oil preferably is from 0.5 to 
2%. 
It is basically possible to include further skin-compatible materials in 
the agents of the present invention. However, an addition of triglycerides 
should be avoided, since these substances markedly reduce the virucidal 
agent activity. It is even possible that earlier findings indicating that 
the simple alcohols such as methanol and ethanol are not suitable for 
killing or deactivating naked viruses resulted from the fact of the skin 
fat being dissolved by the neat alcohols. 
The addition of water to methanol and/or ethanol when intended as a 
virucidal agent of the present invention is not harmful as long as a 
sufficiently high concentration of methanol and/or ethanol is maintained. 
The efficacy of the virucidal agent of the present invention has so far not 
been scientifically elucidated. The hypothesis that the activity is based 
alone on a dehydration effect cannot be correct, as other solvents having 
also a highly dehydrating effect such as propyl alcohol, isopropyl alcohol 
and acetone are inactive. 
The choice of whether the virucidal agents of the present invention 
comprises methanol, ethanol or mixtures of the two alcohols depends on 
costs, toxicity and possible legal regulations of a commercial use of the 
two alcohols. Thus, while methanol is somewhat more efficient than 
ethanol, the former has a higher toxicity than the latter. On the other 
hand, ethanol is more expensive and in many countries is subject to 
special legal provisions that may impede or prohibit the use of ethanol 
for the preparation of the agents according to the invention. Since the 
activity of mixtures of methanol and ethanol increases with an increasing 
proportion of methanol in a linear relation, mixtures of the two alcohols 
may be readily employed as well so that a compromise may be found between 
the advantages and disadvantages of the two alcohols. 
The virucidal agents of the present invention are so highly active that 
mostly within one minute (after a period of 15 minutes at the latest), the 
activity and infectiousness of the most frequent naked viruses are reduced 
by at least 4 powers of ten. 
In practical application, the virucidal agents of the present invention may 
be used either as rinsing agents or applied to the skin by means of 
cotton, a cloth rag or a similar aid to the infected areas of the skin. 
With a view to the deactivating effect of triglycerides it is recommended 
that in a first application the skin fat is removed, and then in a second 
application the virucidal agent of the invention is allowed to display its 
action. The content of glycerol and, optionally, of castor oil, protects 
the skin from being rendered too dry and, thus, acts in a similar manner 
as would a per se desirable restitution of fat. Moreover, it is possible, 
after using the virucidal agents of the invention to treat the skin, to 
apply suitable skin cosmetics containing triglycerides, since the 
disinfection or deactivation, respectively, has been effected in the 
absence of triglycerides. 
The composition and efficacy of the virucides of the present invention is 
further illustrated by way of the following non-limiting examples and 
comparative examples.

EXAMPLE 1 
There are admixed 95 parts by volume of ethanol (96% by volume) with 4 
parts by volume of castor oil and 1 part by volume of glycerol. In a 
second batch, the same amount of ethanol is admixed with 1 part by volume 
of castor oil and 4 parts by volume of glycerol. In accordance with 
further recipes, 97 parts by volume of methanol are admixed with 1 part by 
volume of glycerol and 2 parts by volume of castor oil or with 3 parts by 
volume of glycerol and 1 part by volume of castor oil. 
Investigations with polio virus 1 (Mahoney) in the suspension test show 
that after 1 to 5 minutes, the infectiousness is decreased by from 3 to 5 
powers of ten. 
Comparative tests using corresponding solutions based on acetone, 
isopropanol and propanol did not show any detectable effect. 
After increasing amounts of water had been added to the compositions, it 
was determined that compositions containing at least 70% by volume of 
methanol and/or ethanol are still strongly active. Compositions containing 
only 50% by volume of methanol or ethanol are ineffective. 
Comparative tests using methanol and ethanol with the addition of 1 to 2% 
by volume of triglycerides (Eucerin) showed that these compositions were 
only very weakly active. 
EXAMPLE 2 
Skin regions were rubbed with neat methanol, neat ethanol, aqueous 
methanol, and aqueous ethanol, respectively, for comparative purposes. 
Thereby, these skin areas in the known manner were completely degreased 
and became dry. Comparative tests using the same alcohols containing added 
amounts of glycerol and/or castor oil showed that, although the skin was 
also degreased upon treatment, the skin retained its moisture.