WO1991007942A1

WO1991007942A1 - Nail hardening compositions

Info

Publication number: WO1991007942A1
Application number: PCT/US1990/006987
Authority: WO
Inventors: Harold E. Pahlck; Steven C. Pennisi; Louis J. Veltry
Original assignee: Avon Products, Inc.
Priority date: 1989-11-30
Filing date: 1990-11-30
Publication date: 1991-06-13

Abstract

Nail coating formulations having a nail hardening/strengthening ingredient, specifically, isobutyraldehyde in a concentration of up to about 5 % of the composition by weight.

Description

NAIL HARDENING COMPOSITIONS

TECHNICAL FIELD

The present invention relates generally to cosmetic formulations and more specifically, to a novel formulation which may be applied to human (or other animals) for hardening and/or strengthening the finger or toe nails.

BACKGROUND ART

It is known to include various ingredients in nail coating

formulations for the general purpose for hardening and/or strengthening finger and/or toe nails. Formaldehyde, acetic aldehyde and

glutaraldehyde have all been used for this purpose; however, these ingredients suffer from certain undesirable side effects including irritation of the skin tissue surrounding the nail (i.e. the cuticle area), allergenic reactions to people having sensitive skin, and a bothersome residual odor all of which limit the use of these ingredients in cosmetic nail coating compositions.

DISCLOSURE OF THE INVENTION

Nail coating formulations are provided having a nail

hardening/strengthening ingredient, specifically, isobutyraldehyde, in a concentration of about 5% or less based upon the weight of the

formulation whereby surprisingly nail hardening and strengthening efficacy is achieved without the negative side effects of irritation, allergenic reactions, and a bothersome residual odor. BEST MODE FOR CARRYING OUT THE INVENTION

The nail hardening or strengthening agent contemplated by the present invention may be used in any of the well known forms of "nail coatings" used in the cosmetic industry such as base coats, top coats, pigmented or colorless lacquers or enamels, frosts, creams, menders, strengtheners, and the like. Generally, a typical nail coating has as its basic constituents a film former (nitrocellulose) a resin (toluene- sulfonamide formaldehyde), a solvent (butyl or ethyl acetate), and a plasticizer (dibutyl phthalate). If color is desired a suitable pigment or combination of different pigments and suspension material (clay) also are added. In a manner well understood in the art of formulating nail coatings, the relative proportions of the various basic ingredients mentioned above may be adjusted for optimizing selected characteristics of the nail coating such as its hardeness, strength, gloss, resistance to chipping, flexibility and so on.

In accordance with the present invention, a "nail hardening or strengthening" agent is added to the basic composition described above to improve the hardeness or strength of nails to which the coating is applied. Hardness and strength imparted to the nail helps resist nail breakage, splitting and chipping. Not only does the hardened, stronger nail provide a better supporting surface for the nail coating, leading to a longer effective lifetime for the nail coating, but moreover, hardened or stronger nails resist the tendency to curl as they grow longer. Under current standards of beauty, straight nails as opposed to curled nails generally are considered more aesthetically appealing. The specific nail hardening or stengthening agent of the present invention comprises isobutyraldehyde, a member of the aldehyde family having branched methyl groups (CH₃) and having the formula:

(CH₃)₂ CHCHO. So far as applicants are aware isobutyraldehyde has never been used as a nail hardener or strengthening agent. This ingredient is commercially available as a colorless liquid from a variety of sources including, for example, Eastman Chemicals, Rochester, New York. Without being resistricted to any particular theory, it is believed that the isobutyraldehyde reacts with the keratin or other proteinaceous substances in the nail to effect a cross-linking thereof, thereby leading to an increase in strength and/or in the hardeness of the nail.

When adding the isobutylaldehyde ingredient to a nail coating formulation in accordance with the invention up to about 5% by weight may be employed. However, it has been discovered that when employed at lower amounts, say, about 1% of the composition by weight, strengthening and hardening efficacy still is achieved yet the negative side effects associated with other aldehydes in nail coating formulations are minimized, if not eliminated entirely. Therefore, an amount of isobutyraldehyde in the nail coating formulation of 1% or less by weight is mostly preferred. More specifically, at this mostly preferred amount no irritation of skin tissue surrounding the nail of the cuticle area is experienced, the ingredient is non-sensitive to allergy prone

individuals, and disagreeable odor retention is absent.

In use, the nail coating formulation including isobutyraldehyde as an active nail hardening or strengthening ingredient in accordance with the invention may be applied to the nails by following the use instructlons for the particular nail coating involved. Repeated applications of the nail coating including the isobutyraldehyde ingredient will cause the nails to become strengthened and more hardened compared to their preapplication condition.

The foregoing advantages and other aspects of the invention are further illustrated by the following actual examples which are not to be construd as limiting.

EXAMPLE I

The efficacy of using isobutyraldehyde to strengthen and/or harden nails was tested by measuring the force to depress (bend) a clipped nail sample a fixed distance on a Diastron Rheometer (Diastron Ltd., Surrey, England). All tests were conducted in-vitro on fingernails clipped from young adults. All clipped nail tests samples were washed, for 2 minutes in acetone, and equilibrated (hydrated) at 100% relative humidity for 24 hours. Baseline (pre-test) measurements were then taken prior to treatment. In a first test, the nail clipping samples were treated by being soaked for 30 minutes in a bath of 100% isobutyraldehyde, followed by a 5 minute water rinse. The treated samples showed an average increase in rigidity of 61.8% over the baseline measurement. In a second test, lower concentrations of isobutyraldehyde (1% and 5% aqueous) were tested by soaking nail clipping samples repeatedly for 30 minutes at a time with no after rinse. Following eight such treatments to simulate repeated application the increase in rigidity

EXAMPLE II

A "base coat" composition having the following ingredients was formulated:

41.96000% Ethyl Acetate

23.97000% Butyl Acetate

11.48000% Heptane

9.86000% Nitrocellulose

5.22000% Isopropyl Alcohol

4.00000% To luenesulfonamide/ Formaldehyde Resin

2.00000% Dibutyl Phthalate

1.00000% Isobutyraldehyde

.40000% Benzophenone-1

.05000% Sucrose Benzoate/Sucrose Acetate

Isobutyrate/Butyl Benzyl

.02000% Acrylates Copolymer

.02000% Calcium Pantothenate

.02000% Dimethicone (and) Trimethylsiloxylilicate Total 100.00000%

A sample of the above formulation (e.g. .5 oz. ) was placed in an unmarked vial. In a separate unmarked vial was placed the same formulation without the 1% isobutyraldehyde ingredient (Qs: ethyl acetate). The two vials were then tested for olfactory quality by a trained fragrance evaluator. The formulation of the Example including the 1% isobutyraldehyde was found not to have a pugent or unpleasant odor. Compared to the odor eminating from the other unmarked vial

(without the 14 isobutyraldehyde ingredient) the former had a sweeter more fragrant note.

EXAMPLE III

Utilizing the nail coating of Example II, a Draize-Shelanski allergeniclty assay was preformed on a randomly selected human population of 103 subjects. During the induction phase, (i.e. nine 24 hours periods with a 24 hour hiatus between each application) measured as follows:

5% Isobutyraldehyde (aqueous) 160.34

1% Isobutyraldehyde (aqueous) 11.74

In the third test, a nail coating vehicle comprising a blend of solvents only (ethyl acetate 2 parts, butyl acetate 1 part) was compared to the same vehicle containing 14 isobutyraldehyde. Treatment consisted of a 5 minute soak followed by no rinse. The following increase over the baseline measurement was observed after 6 and then 10 such treatments:

6 10 6 + 10 (Avg.)

Vehicle alone 6.94 10.84 8.94

Vehicle plus 14

isobutyraldehyde 19.34 13.14 16.24

The foregoing tests demonstrate that isobutyraldehyde is effective to increase the rigidly of clipped nail samples. The tests also proved that at a level of 14 an increase in rigidly is achieved, especially after repeated applications.

[See Next Page]

14 reactions of mild erethyma was observed. During the challenge phase (2 weeks later) zero (0) occurances of sensitivity was observed. This test proved that the nail coating of Example II failed to produce any allergenic reactions or challenges among the test population; and that the formulation was essentially non-irritating during the induction phase.

EXAMPLE IV

An aqueous solution of 1% isobutyraldehyde was tested for primary irritation using a single occlusive patch applied repeatedly (4X times) to the same skin site on the backs of 20 randomly selected human subjects under the supervision of a dermatologist. Seventeen (17) of the subjects showed no reaction whereas three (3) subjects showed barely perceptible erythema. Results of this test demonstrate that the 14 isobutyraldehyde solution was essentially non irritating.

It is evident from the forgoing that the present invention provides a "nail coating" composition effective to strengthen or harden nails without the undue side effects of allergenic reaction and irritation. In addition, use of isobutyraldehyde, the active ingredient according to the present invention, provides the further advantage of avoiding any disagreeable residual odor as is the case with prior nail hardening compositions employing other aldehydes (e.g. formaldehyde).

Although the present invention has been fully described above with reference to actual Examples thereof, this was done merely for the sake of illustrating preferred embodiments of the Invention as required by

statute. Obviously, many changes, modifications, and alterations may be made without departing from the principles of the invention.

Accordingly, it is desired that the present invention be limited only by the true spirit and scope of the annexed claims.

Claims

1. A composition which comprises an amount of isobutyraldehyde effective to increase the strength and/or hardness of a nail to which said composition is applied and a carrier.

2. The composition defined by claim 1, wherein the isobutyraldehyde is present in an effective amount of up to 5% by weight.

3. The composition defined by claim 2, wherein the isobutyraldehyde is present in an effective amount of up to 1% by weight.

4. The composition of claim 1, wherein the carrier comprises a film former, a solvent, and a resin.

5. The composition of claim 4, wherein the film former is nitrocellulose.

6. The composition of claim 4, wherein the solvent is butyl acetate, ethyl acetate, or mixtures thereof.

7. The composition of claim 4, wherein the resin is toluenesulfonamide/formaldehyde resin.

8. The composition of claim 1, wherein the carrier comprises a pigment.

9. A composition useful as a base coat, top coat, lacquer, enamel, frost, cream, mender, or strengthener for nails, wherein the improvement comprises the

presence of an amount of isobutyraldehyde effective to strengthen and/or harden a nail to which it is applied.

10. The composition defined by claim 9, wherein the isobutyraldehyde is present in an effective amount of up to 5% by weight.

11. The composition defined by claim 10, wherein the isobutyraldehyde is present in an effective amount of up to 1% by weight.

12. A composition for hardening and/or

strengthening nails which consists essentially of isobutyraldehyde.

13. The composition defined by claim 12, which includes up to 5% by weight isobutyraldehyde.

14. The composition defined by claim 13, which includes up to 1% by weight isobutyraldehyde.

15. A method for treating a nail, which comprises applying to a nail an amount of isobutyraldehyde effective to harden and/or strengthen the nail.

16. The method defined by claim 15, wherein a carrier includes up to 5 wt.% isobutyraldehyde.

17. The method defined by claim 16, wherein the carrier includes up to 1 wt.% isobutyraldehyde.

18. In the method for hardening and/or

strengthening a nail by applying an aldehyde, an improvement which comprises applying an aldehyde consisting essentially of isobutyraldehyde in an amount effective to harden and/or strengthen the nail.

19. The improved method defined by claim 18, wherein up to 5% by weight of isobutyraldehyde is applied.

20. The improved method defined by claim 19, wherein up to 1% by weight of isobutyraldehyde is applied.