Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Biocides; animal or insect repellents or attractants
Reexamination Certificate
1999-09-15
2002-09-10
Dees, José G. (Department: 1616)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Biocides; animal or insect repellents or attractants
C424S401000, C514S844000, C252S380000
Reexamination Certificate
active
06447793
ABSTRACT:
BACKGROUND OF THE INVENTION
The present intention relates to preservative systems. More particularly, this invention relates to a water soluble, broad spectrum preservative system for effectively inactivating water-borne microorganisms in formulations which may differ significantly in composition.
Conventional preservative systems are typically included in personal care products, cosmetic formulations, etc., which include an aqueous phase. Water is required for growth of microorganisms. Since water is an ingredient in many personal care products and cosmetic formulations, they are susceptible to microbial action. Cosmetic and/or other personal care products which do not contain water, that is anhydrous products, do not require extensive preservation to maintain. Microorganisms of general concern to formulators include bacteria (enterics, pseudomonads, staphylococci) yeasts and molds. Microorganisms may require specific environmental conditions to grow. Variations n the physical and chemical state of different compositions enhance or impede microbial growth.
Preservatives and preservative systems known for use against a range of microorganisms are classified as “broad spectrum” preservatives because they are intended to control multiple organisms, such as some combination of the five categories mentioned herein. Conventional preservatives are not typically broad spectrum. They are usually directed to prevent or diminish the growth of one or two of the categories mentioned. Further, various elements known which might be used to control a broad spectrum of microorganisms mentioned, tend to be restricted by limited solubility in water. That is, limited solubility prohibits some constituents from being used in preservative product systems formulated with modest to large amounts of water.
Known broad spectrum antimicrobial systems are limited to specific applications. For example, U.S. Pat. No. 5,670,160 discloses a preservative system meant for use in compositions having an aqueous phase which comprises three (3) components: (1) an organic acid, or salt of same, (2) a monophenyl glyycol ether, and (3) at least one poly (hexamethylenebiguanide) salt, or salt or other guanidine derivative. The '160 patented preservative system displays broad spectrum antimicrobial activity when used at low concentrations. The formulation is known to be used in formulations such as shampoos, creams, lotions and for products in the field of detergents and cleaners. However the '160 patented system is not suitable in formulations used in skin sensitive applications.
Another example of a prior art attempt to realize a broad spectrum antimicrobial is disclosed in U.S. Pat. No. 5,656,591. The antimicrobial agent of the '591 patent includes one or more antimicrobial peptides derived from lactoferrins, and including one or more compounds selected from a group of metal-chelating tocophenol, cyclodextrin, glycerin-fatty acid ether alcohol, EDTA or salts thereof, ascorbic acid or a salt thereof, citric acid or a salt thereof, polyphosphoric acid or a salt thereof, chitosan acid, cysteine and cholic acid. Comparable to the ‘160’ patented system described above, the 591 patented system is not useable in skin-sensitive applications. Further, U.S. Pat. No. 5,490,992 discloses a product and process for reducing microbial contamination by pathogenic or other undesired bacteria by way of a fatty acid monoester mixed with an acid or chelating agent, and a food grade surfactant. The three component formulation provides effective antimicrobial activity synergistically by use of the three components together. For that matter, any of the components recited in the '992 system would not be effective without the other two components to ensure required antimicrobial activity. That is, without the specific combination and concentration of the components in the formulation, the patent asserts that it would not be possible to control microbial growth.
Such formulations would be capable of controlling growth, but would require high concentrations which could adversely affect the organoleptic characteristics of the formulation.
It is believed that the shortcomings mentioned, re prior art preservation systems for use in cosmetics and/or personal care products containing water, relate to the known fact that the effectiveness of water-based antimicrobials varies with pH and other characteristics of the formulation system. Various other preservative are known to be effective under particular conditions, but insufficient to guarantee antimicrobial activity for a broad class of microorganisms. For example, phenol derivatives such as orthophenylphenol, chloroxylenol and resorcinol are used in personal care products but only in very limited quantities because of possible toxicity to humans. The industry is more likely to use ring-substituted derivatives of phenol, relying on its inherent property that the more lipophilic the phenol entity, the greater its antimicrobial activity.
It is another object of the present invention to provide a multiple ingredient, broad-spectrum preservative system displaying an effectiveness which exceeds a summation of the ingredients individually, in a synergistic manner.
In a preferred embodiment, the broad-spectrum water soluble preservative system of the present invention includes an acid or acid derivative (benzoic acid, sorbic acid, esters of parahydroxybenzoic acid, etc) chlorphenesin, a solvent (alcohol, propylene glycol, butylene glycol, glycerine) mixed with phenoxyethanol. A synergy between the elements comprising the invention occurs resulting in an effective broad spectrum preservative system useful in an extended ranges of physical attributes and chemical compositions of cosmetic or personal care products.
An acceptable range of phenoxyethanol in the broad-spectrum water soluble preservative system of the present invention is 40 to 85 percent. An acceptable range of the solvent component is 2 to 48 percent; an acceptable range of the acid or acid derivative is 2 to 20 percent, and an acceptable range of chlorophenesin is added in an amount of 10 to 30 percent to prepare the broad-spectrum water soluble preservative system of the present invention. The resulting preservative system may be used at levels of 2 percent or less as an effective antimicrobial in various products, to be discussed in further detail below.
DETAILED DESCRIPTION OF THE INVENTION
The effectiveness of the broad spectrum antimicrobial preservative system of the present invention is a result of the synergistic antimicrobial effect of the four constituents which comprise the system. That is, the broad spectrum preservative of this invention includes phenoxyethanol, a glycol solvent, an acid or acid derivatives and chlorphenesin in varying amounts, whereby 2 percent or less of the system in a product by weight is effective. The synergistic effect of the combination of the four separate components realizes broad spectrum antimicrobial range. However, it should be noted that each of the four ingredients of the invention may display antimicrobial activity when acting alone.
Minimum inhibitory concentrations (MIC) were determined for Germazide WS and Germazide MPB using inocula of gram negative rods, gram positive rods, yeast and mold. The MIC is defined as the lowest concentration of test agent inhibiting visible growth.
All percents by weight are based upon the total preservative composition weight.
A cosmetic composition comprises up to 2% by weight of the preservative of the invention; and up to 98% by weight of inert non-toxic topically acceptable carrier ingredients suitable for topical application to the skin of a warm-blooded animal, such as a person. Here all percents by weight are based upon the total cosmetic composition weight.
REAGENTS FOR GERMAZIDE™ (WS and MPB)
State/
Material
Source
City
Country
Chlorphenesin
Kraemer
Hamburg
Germany
Phenoxyethanol
Universal
S. Edison
New Jersey
Sorbic acid
Spectrum
Gerdena
California
Benzoic Acid
Ruger
Irvington
New Jersey
Methyl paraben
Universal
S. Edison
New Jers
Aust Duncan
Ross Michael
Spiegelman Stephen
Darby & Darby
Dees Jos,e G.
Lamm Marina
The Collaborative Group, Ltd.
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