Note: Descriptions are shown in the official language in which they were submitted.
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Background of the Invention
Liviny organisms, inc]uding microorganisms such as
bacteria, require the bioloyical oxidation of
carbohydrates as an eneryy source. During this succession
of oxidation reactions, ylycoyen, the form in which
carbohydrates are stored in an animal body, is converted
to carbon dioxide and water. This conversion may be
divided into three stayes, (a) ylycogen is broken down into . :
its component D-ylucose molecules; ~b) in glycolysis,
D-glucose is itself broken down into three carbon compounds;
and (c) such compounds, in respiration, are converted
into carbon dioxide and water.
The last step of-glycolysis is the reduction of - ~;
pyruvic acid to lactic acid accordiny to the followiny
equation:
CH3COCOO + NADH + ~ = CH3CHOHCOO ~ NAD~ (1~ i.
Pyruvate Reduced Lactate Nicotinamide ~ :
nicotinamide adenine
adenine dinucleotide
dinucleotide
The above reaction is catalyzed by a set of enzymes
~ collectively referred to as "lactate dehydroyenase".
:. This reaction is i~portant for the regeneration of
~AD which is required for the conversion of 3-phosphoylycer-
aldehyde to 1,3~diphosphoglycerate in the Embden-
2~ ~eyerhof-Parnas (EMP) pathway, for the conversion of pyruvate
to acetyl.-coenzyme A, called "acetyl CoA", and for the
conversion of isocitrate to oxalosuccinate t 2-ke~toglutarate
; to succinyl-coenzyme A, and mala~.e to oxaloacetate in the
tricarboxylic acid cycle (aerobic oxidation of ylucose)O
3~ One known technique for limitiny the growth of
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harmful bacteria or other microorganisms is by the addition
of an inhibitor of an enzyme such as an antibiotic. One
problem wlth this approach is that if the bacteria are not
destroyed rapidly, a mutant population may arise which is
not affected by the inhibitor. For example, there are now
several strains of staphylococcus which are resistant
to the antibiotic penieillin. Another problem with
this approach is the serious allergic reaction of certain
patients to the presence of such foreign antibiotic
substances.
It is known that the growth of microorganisms can
be reduced by lowering the pH level of their environment.
~or example, microorganisms ~row substantially slower or
are killed at a pH of 3 in comparison to a pH of 4. One
reason for this is that a low pH environment is deleterious
to cytochrome C which is necessary for the oxidative
phosphorylation path.
Mieroorganisms such as baeteria are also adversely
effected by contact with aleohols which serve to
denature the protein of the microorganisms. Thus, alcohol
; is a well known bactericide.
It is also known that the unpleasant odor due to
perspiration is caused by the attack of bacteria on the
secretions of the sweat glands. U.S. patent 3,124,506
discloses a number of eompositions which are-stated to be
useful as an inhibitor of foot odor or as an underarm
deodorant. There is no disclosure of any sug~ested
meehanism for the effeetiveness of such eompositions for
this purpose. ~lowever, one set of nonaqueous compositlons
including malie aeid,he~achlorophenef and isopropyl
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alcohol, is disclosed for use as a deodorant. Another set
of compositions is disclosed for use as a dentifrice and
prophylactic nose and throat composition including a
water based mixture of calcium lactate, malic acid,
or lactic acid and calcium malate, both in water. There
is no suggestion of using an alcohol composition in this
formulation or that the composition could exclude
calcium.
- Summary of the Invention and Objects ~ -
In accordance with the present invention, a solution
has been provided having excellent biostatic activity for
use as a deodorant, to treat acne, chapping, dandruff,
"athlete's foot", or psoriasis, and as a cleanser ar~
disinfectant. A biostat or biostatic material is defined
as a chemical composition which inhibits the growth of i~
liying cells such as microorganisms (e.g~, bacteria).
The composition includes effective quantities of a lactic
acid yielding compound (e~g., lactic acid), an alcohol,
and water, and has a pH level no greater than about 3Ø
The biostatic ac~ivity of thessol~tion derives from three
primary factors. Firstly, the presence of lactic acid
thermodynamically drives the reversible reaction of
equation (1) to the left to reduce the concentration of
NAD . As set forth above, NAD is essential in the
2~ production of energy in microorganisms. Secondly, since the
solution includes no metal ion, it is not buffered and so
has a highly acidic pH level which is detrimental to the
function of cytochrome Cl a~so important in energy
production oflmicroorganisms. Thirdly, the presence of
the alcohol denatures; the protein oi the microorganisms.
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When the solution is emplo~ed as a disinfectant and
cleanser, in addition to the above biostatic activity, the
lactic acid reacts with soap to displace the sodium ion
of typical soap films to form long chain fatty acids which
S are soluble in the alcoholic solution. Thus, difficult to
remove soap deposits are readily washed awa~ in the
alcoholic solution without large expenditures of effort.
It is an object of the present invention to
provide a solution having excellent biostatic activity in ;
- 10 comparison to the prior art.
It is a further object of the invention to provide
such a solution which does not cause an allergic
- reaction.
It is another object of the invention to,provide
a solution with activity unaffected by potential
growth of mutant microorganism populations. ;~
It is a further object of the invention to provide `
a solution effective as a deodorant and bactericide.
- It is a further object of the invention to provide
a solution effective for the treatment of "athlete's oot".
It is a further object~of the invention to provide
~; such a solutioh capa~le of treating skin disorders such as
chapped skin, dandruff, and psoriasis.
It is an additional object of the invention to provide
such a solution which functions as an effective cleanser
and disinfectant.
Further objects and features of the invention will
be apparen~ from the following description of the preferred
e~bodiments.
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Detailed Description of the Preferred Embodiments
The biostatic solution of the present invention
includes a lac~ic acid yielding compound, a volatile
alcohol, and water. The term "lactic acid yielding coMpound"
is defined to include lactic acid, compounds hydrolyzable
to lactic acid and mixtures of the same. Substances
hydrolyzable to lactic acid include lactide, lactyl lactic
acid, and higher polymers, ethyl and methyl lactate, and
mixtures of the same. For simplicity of description, the
specification will refer to lactic acid as the lactic
acid yielding compound.
For convenience of reference, equation (1) set
forth above is repeated as f~llows:
CH3COCOO + NADH + ~ CH3CHOHCOO + NAD (1)
Pyruvate Reduced Lactate Nicotinamide
nicotinamide adenine
adenine dinucleotide
dinucleotide
By well known principles of chemical equilibria, it is -
- 20 apparent that an increase in lactate ion or its source,
lactic acid, in the above ~uation will drive the reaction
to the left~ and so reduce the production of NAD . As
set foi-th above, th~is reduces the energy source for the
yrowth of microorganisms.
It has been determined that the lactic acid
concentration in perspiration varies from 0.147 to 0.371
weight/vol~ne percent with a mean value of 0.232 percent
(Ralph G. Harry, The Principles and Practice of Modern
Cosmetics, Vol. 1, Chemical Publishing Co., New York,
3Q (1962), p. 469). For the present formulation to be
effective as a deodorant in the presence of perspiration,
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the additional lactic acid concentratio~ should be
substan~ial in comparison to that present in the
~erspiration. A suitable lower value for this purpose of
about 0.5 weight/volume percent of lactic acid will be
effective for use as a deodorant for a typical human
application.
In view of the foregoing, a suitable ranye of
lactic acid in the composition is from about 0.5% to 2 to
4% or more. The maximum value is determined as that which
would cause undue irritation in the particular area of the
subject treated. Of course, this limitation is not present
when the solution is employed as a combination cleanser
and disinfectant as set forth hereinafter.
The foregoing lower limitation of 0.5% is related -
to the destruction of bacteria which co~bines with
perspiration to yield an unpleasant odor. It should be
understood that other living cells such as fungi and
yeast are also inhibited by the same reduction in the
source of energy. It is assumed that the foregoing lower
limit would be comparable to that which would be effective
in the reduction of such other living cell growths on
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the skin. '
Lactic acid also serves to lower the pH of the
solution to a level between about 2.0 and 3.0 which
; 25 inhibits the function of cytochrome C, which also reduces
the energy source for growth of microorganisms as set
forth aboveO It is preferable to maintain the pH of the
solution at a level below about 3.0 to take advantage
of this effect. Thus, it is preferable that the solution
exclude any substantial amount of metal ion compound which
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would have a buffering efect in combination with the acid.
It is noted that most soaps are alkaline and so
increase the pH of the skin to levels on the order of
8 to ~. At such pH levels, the skin is highly susceptible
to bacteria growth before it returns to its normal
acidic levels. This is a particular problem with
unhealthy skin which takes a longer time to return
to its normal pH levels. This problem is avoided by
the use of the present solution which actually lowers
the pH level of the skin to inhibit growth of bacteria
or the like.
The second element in the present composition is
` a- alcohol which is known to be an effective bactericide
by denaturation of the protein content of bacteria or
the like. In addition, it has a relatively low surface
tension enabling it to penetrate deeply into crevices in ~ ~ -
the surface of the skin and into the pores. Furthermore,
by attacking the lipoproteins in the microorganism~i cell
membranes, the alcohol permits more effective penetration
oi the solution into the cells. Another function of the
alcohol is dependent on its high volatility. Thus, when
it is present in a high proportion, the mixture vaporizes
rapidly, an important feature for use as a deodorant
or the like.
Suitable alcohols which may be employed ln the
above compositions are the lower alkyl alcohols such as
- methyl, ethyl, n-propyl, and isopropyl alcohol. It is
known that higher alcohols have better bactericidal
efficiency but lower solubility in water, lower volatility,
and a higher cost. Isopropyl alcoh~ol is a pre~erable
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balance for all of these factors.
The concentrat;on of the alcohol is selected to be
at least a minimum quantity for good efficacy o~ biostatic
activity as well as causing at least a minimum rate of
evaporation of solution after application. For application
to a human subject, the maximum concentration is
determined by an acceptable level of irritation to tlle
particular area of contact with the skin. Suitable
concentrations of isopropyl alcohol may range between '
30 and 90~ (volume/volume) while an optimum
concentration is on the order of 50%.
The remain,der of the solution comprises water
which serves as a diluent for adjustment of the desired --
concentrations. Thus, the bulk of the remainder of the
solution after addition of alcohol and lactic acid
comprises ~ater. The water also serves as a medium for '~ ' '
ionizing the lactic acid for reduction of the pH level -
, of the solutionO
The mechanism for dermatological application as a
deodorant as for underarm or foot odors is for the
solution to attac'k the',bacteria in the vicinity of the
secretions of the sweat glands. Since such bacteria cause
the unpleasar.t odors in such secretions, the present
solution is particularly effective as a deodorant. When
used as a deodorant, a maximum alcohol content should be
employed,as this increases the rate of evaporation.
The present solution may also serve as a bactericicle ,~
in treatment of acne. It is known that coryne bacterium_ ',
acnes and other bacteriaisecrete lipases which hydrolyze
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fats in the sebum,~ producing long chain fatt~ acids which
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are irritating to the f~llicles. The present solution
serves to prevent the follicular inflammation by inhibiting
the growth of the lipase secreting bacteria.
Chapped skin, dandruff and psoriasis are all
abnormal skin conditions which may be aggravated by -
secondary microbial infections. It has been found that
the present solution is an effective treatment for such
abnormal skin conditions. The present solution can
also be employed in the treatment of fungus infections
such as "athlete's foot" and yeast infections.
The present solution is also effective as a -~
- post-scrub lotion, especially for persons re~uired
to wash their hands frequently such as medical doctors.
The present solution leaves the skin moist after ;
application and at a pH level which minimizes bacterial
growth. -~
In addition,to;the foregoing use as a treatment
for human subjects, the solution of the present invention
; is also particularly effective for simultaneous
cleaning and disinfecting of a dirty surface. It has
been found that application of the solution removes
dirt, especially in the form of dirty soap films with
minimal effort while simultaneously disinfecting the
surface. The ease of removal of the dirt such as soap is
believed to be due to the following mechanism. The soap,
formed of a metal (e.g., calcium) salt of a fatty acid,
reacts with the lactic acid component of the solution to form
a fatty acid which is highly soluble in the alcoholic
solution. Such fatty acid is dissolved in the alcohol ~ -
and rapidly removed from the surface without the necessity
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for excesslve rubbing.
It should be apparent that other additives may be
added in minor proportion to augment the above solutions.
~or example, scents may be added to form an after shave
lotion or scented deodorant. Also, humec-tants such
as glycerine or propylene glycol may be added to a
solution, or mineral oil may be used to increase lubricity
for such use as a hand lotion. Furthermore, malonic
acid may be added to the deodorants to reduce the amount
; 10 of perspiration. Finally, urea may be employed to
assist in the inhibition of yeast cell growth.
For convenience, the solution of the present
invention may be prepared ~y the consumer at home from
its components. Thus, a lactic acid ~orming compound
in solid form such as a tablet or powder:may-be ~dt~ed
to a commercially available aqueous alcoholic solution
(e.g., isopropyl alcohol). Lactide is a suitable lactic
acid yielding solid~ The solution of the present invention
may also be prepared by the consumer by adding a commercially
2Q available a~ueous alcoholic solution to an aqueous solution
of a lactic acid ,forming compound.
A further disclosure of the nature of the present
invention is provided by the following specific examples ;~
of the practice of the invention. It should be understood
that the data disclosed serve only as examples and are
not intended to limit the scope of the invention. The
following examples will utilize a three-digit number as a
code for the formulations. The first digit refers to the
lactic acid concentration in weight/volume percent. The
second and third digits refer to the percentage of
isopropyl alcohol (volume/volume). The remainder of the
formulation is water.
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xample 1
Formula 230 is a satisEactory underarm deodorant,
but has a xelatively low evaporation rate. Formula 260 is
preferred for this purpose as having a rapid evaporation
rate without being unduly irritating. Yormula 460 is
employed for persons with severe body odor problems. The ~`
same formulations may be employed as a foot deodorant
or treatment for "athlete's foot" or other fungus
; infections.
Example 2
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Formulation 260 is employed for the treatmellc of
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acne. If a person has a relatively non-sensitive
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skin, the stronger for-.ulation, 460, is preferable. For
; very difficult cases of acne, formulations 480, or
660 are employed.
Exam~le 3
Formulation 230 is employed as a treatment for
aandruff effectively since residual moisture in the hair
is not detrimental. Formulations 260 or 460 are
employed for more severe cases of dandruff.
.
Example 4
Formulations 260 and 460 are employed for the
treatment of chapped skin. If formulation 460 is too `;
irritating for severe cases, alternating use of
formulations 260 and 460 are effective.
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