Anti-irritant and desensitizing compositions and methods of their use

Compositions and methods for reducing the adverse reaction of skin to chemicals and compositions that contact the skin, e.g., topical cosmetic and pharmaceutical preparations, and to contact physical irritants. The active ingredient of the composition of the invention comprises a hydro-alcoholic extract of Cola nitida.

BACKGROUND OF THE INVENTION 
This invention relates to compositions for reducing adverse reactions of 
the skin to chemicals and compositions that contact the skin, e.g., 
topical cosmetic and pharmaceutical compositions, and for reducing such 
adverse reactions caused by certain kinds of physical contact. 
Exposure of human skin to chemicals contained in topical cosmetic and 
pharmaceutical compositions can result in adverse reactions to the skin, 
including irritation response and contact sensitization of the skin. As 
used herein, the term cosmetic and pharmaceutical compositions is used in 
the widest sense of the term, and encompasses any composition that is 
applied to the skin for a beneficial effect. As used herein, contact 
sensitization of the skin refers to adverse systemic immunological 
reactions of the skin, e.g., itching, burning, swelling or redness. 
Irritation response of the skin involves similar symptoms in which the 
systemic immune system plays no role. 
A small, but significant segment of the population is particularly prone to 
such irritation response and contact sensitization. As a consequence, the 
use of a wide variety of topical preparations for the skin by this segment 
of the population is, at best, an unpleasant task. For example, 
compositions containing paramino benzoic acid (e.g., sunscreens) or Balsam 
of Peru are known to cause contact sensitization, and certain chemicals, 
e.g., vasodilators and surfactants are known to cause irritation response 
when used by certain persons. 
In addition, certain types of physical contact with human skin can cause 
irritation response of the skin. For example, the removal of hair from 
human skin by waxing methods is known to cause irritation to most, if not 
all, persons who have waxing treatments. Hereinafter, the types of 
physical contact that cause irritation response of human skin are referred 
to as "contact physical irritants." 
SUMMARY OF THE INVENTION 
An object of this invention is to provide a composition and method for 
reducing the irritation response and contact sensitization of human skin 
to chemicals and compositions that contact the skin, e.g., topical 
cosmetic and pharmaceutical preparations. 
Another object of this invention is to provide a composition and method for 
reducing the irritation response of human skin to contact physical 
irritants. 
We have discovered that compositions containing a hydroalcoholic extract of 
Cola nitida in a carrier are useful for reducing adverse reactions of the 
skin to chemical irritants and to contact physical irritants. Preferably, 
the composition of the invention comprises at least 2.5% by weight of the 
hydroalcoholic extract of Cola nitida. 
As used herein, the term "carrier" shall include materials that are 
suitable for use in contact with the skin and which, when combined with 
the Cola nitida extract in the composition of the invention, take a form 
that is suitable for application to the skin, e.g., the form of a liquid, 
gel, ointment, cream, lotion or the like. 
The compositions of the invention may be applied in effective amounts to 
the skin in any suitable manner at about the time the skin is exposed to a 
chemical irritant or a contact physical irritant. Preferably, they are 
applied to the skin in an effective amount shortly before (e.g., less than 
about half an hour before, preferably less than about 15 minutes before) 
the skin is exposed to a chemical or contact physical irritant. It is 
within the scope of the invention, however, to apply the composition of 
the invention simultaneously with (e.g., as part of a composition 
containing a chemical irritant) or shortly after (e.g., less than about 
half an hour after, preferably less than about 15 minutes after) the skin 
is exposed to a chemical or contact physical irritant. 
In use, the composition of the invention prevents the induction of any 
noticeable adverse systemic immunological reaction of the skin (i.e., it 
prevents the induction of contact sensitization) in some cases and reduces 
the extent of contact sensitization in other cases. Similarly, in use the 
composition of the invention prevents the onset of an irritation response 
to the skin in some cases and reduces the extent of irritation response to 
the skin in other cases.

DETAILED DESCRIPTION OF THE INVENTION 
Cola nitida (also known as Cola nitida semen) is a plant that includes Cola 
nuts. Extracts useful in the composition of the invention may be obtained 
by crushing the Cola nuts and then extracting the crushed nuts with a 
hydroalcoholic solution (e.g., a 50% aqueous solution of ethyl alcohol at 
25.degree. C.). After filtering, the extract is preferably concentrated by 
drying (e.g., spray drying) to obtain either a solid or liquid extract 
(depending on the extent of drying). Suitable Cola nitida extracts may be 
obtained from Indena S.P.A., Gruppo Inverni Della Beffa, Milan, Italy. 
Suitable hydroalcoholic extracts of Cola nitida for use in this invention 
include hydroalcoholic extracts of Cola nitida that have been treated 
(either before or after they are concentrated by drying) to alter the 
color of the extract (e.g., to lighten its color) and/or to diminish its 
odor. Such treatment can be accomplished, for example, by chromatographic 
techniques. 
In one embodiment of this invention, the composition of the invention 
comprises at least 2.5% by weight of Cola nitida extract in a suitable 
carrier. In other embodiments, the composition comprises at least 5% by 
weight of the Cola nitida extract (e.g., 10-15% by weight of the extract). 
Upon application to the skin, the composition of the invention is effective 
in reducing adverse reactions of the skin to a number of chemical 
irritants. For example, when a composition containing 10% by weight of 
Cola nitida extract was applied by a panel of persons (who were chosen to 
be on the panel because of their sensitivity to a variety of irritant 
compounds) just before the persons applied to their skin a known irritant 
(Balsam of Peru), the irritation response of the panel to the irritant was 
significantly reduced. In addition, panelists who were known to exhibit an 
irritation response to paramino benzoic acid containing sunscreens applied 
a composition containing 10% by weight of Cola nitida extract composition 
prior to applying such a sunscreen with the following results: 86% of the 
panelists demonstrated a noticeable improvement in resistance to sunscreen 
irritation (slightly more than half of which demonstrated a highly 
significant improvement), 10% of the panelists had no change in response 
to sunscreen irritation and 3% (one person) had a decrease in resistance 
to sunscreen irritation. 
Preferably, the compositions of the invention are applied to the skin 
shortly before (about 30 minutes or less, preferably about 15 minutes or 
less) a cosmetic or pharmaceutical composition containing a chemical 
irritant is applied to the skin. 
The composition of the invention may also be applied shortly after (less 
than about 30 minutes after, preferably less than about 15 minutes after) 
a cosmetic or pharmaceutical composition containing a chemical irritant is 
applied to the skin. In addition, the Cola nitida extract may be included 
in effective amounts in compositions containing chemical irritants, 
thereby permitting the simultaneous application of the Cola nitida extract 
and the irritant to the skin. 
The composition of the invention may also be applied to the skin shortly 
before (about 30 minutes or less, preferably about 15 minutes or less) the 
skin is waxed for the purpose of removing hair therefrom. We have found 
that the use of our composition in such a manner reduces the irritation 
resulting from removing hair by such waxing techniques. The composition of 
the invention may also be applied shortly after (less than about 30 
minutes after, preferably less than about 15 minutes after) the skin is 
waxed for the purpose of removing hair therefrom. We believe also that the 
composition of the invention would be useful to reduce the irritation 
response of the skin to other contact physical irritants such as, for 
example, harsh environmental conditions and abrasive clothing. 
A wide variety of materials may be used as carriers in the composition of 
the invention. Examples of such carriers include hydroalcoholic solutions 
and water and oil emulsions. In addition, the compositions of the 
invention may include other active ingredients for the skin as well as one 
or more fragrances, preservatives, emulsifiers, and other materials of the 
type that are conventionally included in cosmetic and pharmaceutical 
compositions. Among the wide range of active ingredients that may be 
included in the composition of the invention, but which do not comprise 
part of the invention, are vitamins, sunscreens, antioxidants, free 
radical scavengers, lipids, glycolipids, and other materials that have 
desirable cosmetic or pharmaceutical effects on the skin. 
The following non-limiting Example illustrates a composition of the present 
invention. 
EXAMPLE 
A formulation comprising an oil in water emulsion was prepared by combining 
the following ingredients in the sequence and manner described below: 
EXAMPLE 1 
______________________________________ 
Example 1 
Ingredient Parts By Weight 
______________________________________ 
Sequence 1 
Hetester PCA 10.00 
(an oil) 
Hetester PHA 5.00 
(an oil) 
Parabens 0.15 
(a preservative) 
Glyceryl mono stearate 
1.30 
(a wax) 
MYRJ 52 1.20 
(an emulsifier) 
Emerest 2486 1.00 
(an oil) 
Sequence 2 
Cola nitida Powder 10.00 
Deionized Water 38.15 
Butylene Glycol 6.00 
(a solubilizer) 
Emeressence 1160 .05 
(a preservative) 
Parabens .35 
(a preservative) 
Sequestrene .10 
(a chelating agent) 
Sequence 3 
Carbopol 934 20.00 
(2% aqueous solution) 
(a thickener) 
Sequence 4 
Deionized Water 3.00 
TEA 99% 0.40 
(a neutralizer) 
Sequence 5 
Deionized Water 3.00 
Germall 115 0.3 
(a preservative) 
______________________________________ 
The above ingredients were combined by the following procedure: 
(1) the Sequence 1 ingredients were combined and heated to 78.degree. C., 
with mixing; 
(2) the Sequence 2 ingredients were combined and heated to 78.degree. C., 
with mixing, until the Parabens dissolve; 
(3) the Sequence 3 ingredient was added to the Sequence 2 ingredients, with 
mixing; 
(4) the Sequence 1 ingredients were added to the Sequence 2/3 ingredients, 
with mixing; 
(5) the mixture of the Sequence 1-3 ingredients was cooled to 45.degree. 
C.; 
(6) the Sequence 4 ingredients were added to the cooled mixture of Sequence 
1-3 ingredients, with mixing; 
(7) the resulting mixture of Sequence 1-4 ingredients was cooled to 
38.degree. C.; 
(8) the Sequence 5 ingredients were added to the cooled mixture of Sequence 
1-4 ingredients, with mixing; and 
(9) the mixture of Sequence 1-5 ingredients was cooled to 25.degree. C.