Patent Grant
6841162
1. Field of the Invention
The present invention relates to a novel cosmetic or dermatological composition containing, as an active substance, at least one natural or recombinant spider silk protein, or an analog of such a protein. More particularly, the present invention relates to compositions in the form of hair products, skincare products, make-up products or antisun products based on a spider silk protein.
2. Discussion of the Background Art
The use of natural or plant proteins is well known and has been widely practiced in the cosmetics field, in particular the use of silk proteins from the insect Bombyx mori, more particularly described in Biomaterials Ed. D. Byrom, Stocktompress, 1-54, (1991). However, these silk proteins do not have good mechanical properties in the form of threads or films and cannot therefore satisfactorily fulfill their functions as film-forming agents.
Spider silk proteins have been characterized by Lucas et al., Adv. Protein Chem. 13:107-242, (1958); Andersen, Comp. Became. Physiol. 35:705-711, (1970); Denny M W, J. Exp. Biol., 65, 483-506, (1976); and Lucas F, Discovery, 25, 20-26, (1964). They are known for their good mechanical and elastic properties.
It has now been discovered that, in addition to their known properties, spider silk proteins give cosmetic or dermatological compositions unexpected properties, in particular enhancement of the moisturizing or plasticizing effect. Spider silk proteins moreover behave as good water-resistant film-forming agents, and especially have a low surface density.
Accordingly, it is an object of the present invention to provide a cosmetic or dermatological composition containing an effective amount of at least one natural or recombinant spider silk protein, or an analog of such a protein.
Various other objects, features and attendant advantages of the present invention will be more fully appreciated as the same becomes better understood from the following detailed description when considered in connection with the accompanying Figures.
FIG. 1: The peptide sequence of a natural spider silk protein, Spidroin major 1 (SEO ID NO:1). The “-” are added to show the alignment of the repeating units.
FIG. 2: The peptide sequence of a natural spider silk protein, Spidroin major 2 (SEQ ID NO:2). The “-” are added to show the alignment of the repeating units.
FIG. 3: The peptide sequence corresponding to residues 92 to 706 of the natural spider silk protein. Spidroin minor 1 (SEQ ID NO:1). The “-” are added to show the alignment of the repeating units.
FIGS. 4A-B: The amino acid sequence of a monomer (SEQ ID NO:3) and of a polymer (SEQ ID NO:4) of a Spidroin major 1 analog.
FIGS. 5A-B: The amino acid sequence of a monomer (SEQ ID NO: 5) and of a polymer (SEQ ID NO: 6) of a Spidroin major 1 analog.
FIGS. 6A-B: The amino acid sequence of a monomer (SEQ ID NO:7) and of a polymer (SEQ ID NO:8) of a Spidroin major 1 analog.
FIGS. 7A-B: The amino acid sequence of a monomer (SEQ ID NO:9) and of a polymer (SEQ ID NO:10) of a Spidroin major 2 analog.
According to one specific embodiment of the cosmetic compositions according to the present invention, the spider silk proteins are preferably recombinant spider silk proteins.
Although natural proteins can be used according to the invention for the formulation of cosmetic or dermatological products, in particular on account of their good biocompatibility and biodegradability, the genes coding for these silk proteins have a certain level of genetic instability due to the repetitions in the nucleotide sequences, which does not make it possible to obtain good reproducibility of their physicochemical properties.
In contrast, recombinant spider silk proteins have the advantage of having a predetermined peptide sequence which can be designed as a function of the physicochemical properties of strength, or alternatively of elasticity, required for the various cosmetic or dermatological applications desired.
According to the invention, the compositions can contain, in an effective amount, at least one natural or recombinant spider silk protein, corresponding to Spidroin major 1 described by Xu et al., PNAS, USA, 87, 7120, (1990), to Spidroin major 2 described by Hinman and Lewis, J. Biol. Chem., 267, 19320, (1922), or alternatively to the minor Spidrions described in patent application WO 95/25165. The peptide sequences are recited
When the compositions according to the present invention contain at least one recombinant spider silk protein, this protein comprises a repeating unit of amino acids corresponding to one of the sequences (I), (II), (III) and/or (IV) below.
The following abbreviations are used to identify the amino acids:
[(XGG)w(XGA)(GXG)x(AGA)y(G)zAG]p (SEQ ID NO: 11) (I)
in which:
X corresponds to tyrosine or to glutamine,
w is an integer equal to 2 or 3,
x is an integer from 1 to 3,
y is an integer from 5 to 7,
z is an integer equal to 1 or 2, and
p is an integer such that the molecular weight of the protein is between 10 and 400 kDa, and/or
[(GPG2YGPGQ2)a(X′)2S(A)b]p (SEQ ID NO: 12) (II)
in which:
X′ corresponds to the amino acid sequence GPS or GPG,
a is equal to 2 or 3,
b is an integer from 7 to 10, and
p is an integer such that the molecular weight of the protein is between 10 and 400 kDa, and/or
[(GR)(GA)l(A)m(GGX″)n(GA)l(A)m]p (SEQ ID NO:13) (III)
and/or
[(GGX″)n(GA)m(A)l]p (SEQ ID NO:14)
in which:
X″ corresponds to tyrosine, glutamine or alanine,
1 is an integer from 1 to 6,
m is an integer from 0 to 4,
n is an integer from 1 to 4, and
p is an integer such that the molecular weight of the protein is between 10 and 400 kDa.
According to another embodiment of the present invention, the cosmetic or dermatological compositions can contain an effective amount of at least one analog of a spider silk protein.
According to the invention, the term “analog” refers to peptides which imitate the repeating units of amino acids derived from natural spider silk proteins and the profile of variation between the repeating units without modifying their three-dimensional conformation. It is thus possible to design a peptide sequence so as to obtain the physicochemical properties required for the various cosmetic or dermatological applications desired.
In this respect, patent applications WO 91/16351 and EP 452,925, each incorporated herein by reference, describe the synthesis of peptide analogs with elasticity properties which are enhanced on account of the elongation of the polyalanine sequence. Conversely, it is possible to reduce the elasticity of the protein by removing the polyalanine sequences. Similarly, when it is desired to obtain a less rigid protein, its suffices to replace the glycine residues with serine residues.
Moreover, patent application WO 94/29450, incorporated herein by reference, describes the synthesis of peptide analogs containing preferred codons which are specific for the host organism. The reason for this is that it is well known that the expression of foreign genes is more effective when the codon of preferred use by the organism is used. Such peptide analogs can be synthesized from DNA monomers of 300 to 400 bp coding for one or more amino acid repeating units, which are then combined to form a complete gene coding for an analog. Examples of peptide analog sequences are given in
Various methods for synthesizing these peptide analogs are known and have been described by Ausubel et al., Current Protocols in Molecular Biology § 8 (John Wiley & Sons 1987, (1990)), incorporated herein by reference. This involves, inter alia, site-directed mutagenesis of polynucleotides coding for a functional fragment of a spider silk protein.
The natural spider silk proteins can be harvested according to the method described by Work et al., J. Arachrol., 10,1-10, (1982) and in patent application EP 452,925. Both of these references are incorporated herein by reference.
The recombinant proteins can be produced by transformed prokaryotic or eukaryotic systems containing the cDNA coding for a spider silk protein, for a fragment of this protein or for an analog of such a protein.
The systems for expressing proteins are well known and have been described by Maniatis, Molecular Cloning, A Lab Manual (1982) and Sambrook et al., Molecular Cloning, volumes 1, 2, 3 (Cold Spring Harbor Laboratory: Cold Spring Harbor, N.Y., (1989)). Both of these references are incorporated herein by reference.
The prokaryotic systems include Gram-negative bacteria or Gram-positive bacteria, such as Escherichia coli or Bacillus subtilis. The prokaryotic expression vectors can include an origin of replication which can be recognized by the host organism, a homologous or heterologous promoter which is functional in the said host, the DNA sequence coding for the spider silk protein, for a fragment of this protein or for an analogous protein, and a selection gene such as an antibiotic-resistance gene.
The eukaryotic systems include yeasts (Saccharomyces cerevisiae) and insect, mammalian or plant cells. In this case, the expression vectors can include a yeast plasmid origin of replication or an autonomous replication sequence, a promoter, a DNA sequence coding for a spider silk protein, for a fragment or for an analogous protein, a polyadenylation sequence, a transcription termination site and, lastly, a selection gene.
In the compositions of the invention, the expression “effective amount” of at least one natural or recombinant spider silk protein, or of an analog, corresponds to a proportion of from about 10−4 to about 30% by weight, but preferably from 10−3 to 15% by weight, relative to the total weight of the composition, it being possible for this proportion to vary as a function of the type of cosmetic or dermatological composition. These ranges include all specific values and subranges therebetween, such as 10−2, 0.1, 0.2, 0.5, 1, 2, 5, 10, 20 and 25% by weight.
According to a first specific embodiment, the compositions according to the invention are anhydrous and comprise a fatty phase in a proportion generally of from about 10 to about 90% by weight relative to the total weight of the composition, where the fatty phase containing at least one liquid, solid or semi-solid fatty substance. This range for the fatty phase includes all specific values and subranges therebetween, such as 20, 30, 40, 50, 60, 70 and 80% by weight.
The fatty substances can be chosen from oils, waxes, gums and/or so-called pasty fatty substances.
A—The oils in the fatty phase can be of mineral, animal, plant or synthetic origin, and may or may not be volatile at room temperature.
Oils of mineral origin which may be mentioned in particular are liquid paraffin and liquid petroleum jelly.
Oils of animal origin which may be mentioned in particular are squalene and squalane.
Oils of plant origin which may be mentioned in particular are sweet almond oil, beauty-leaf oil, palm oil, avocado oil, jojoba oil, sesame oil, olive oil, castor oil and cereal germ oils such as, for example, wheatgerm oil.
Synthetic oils which may be mentioned in particular are:
(1) esters of the following formula:
R1—COOR2
in which:
R1 represents a higher fatty acid residue containing from 7 to 20 carbon atoms, and
R2 represents a hydrocarbon-based radical containing from 3 to 30 carbon atoms.
These ranges of carbon numbers include all specific valves therebetween.
Among these esters, mention may be made in particular of: purcellin oil, butyl myristate, isopropyl myristate, cetyl myristate, isopropyl palmitate, butyl stearate, hexadecyl stearate, isopropyl stearate, octyl stearate, isocetyl stearate, decyl oleate, hexyl laurate, isononyl isononanoate and esters derived from lanolic acid, such as isopropyl lanolate and isocetyl lanolate.
Other synthetic oils which may also be mentioned are isododecane, isohexadecane, polyisobutenes and hydrogenated polyisobutene, as well as acetylglycerides, octanoates and decanoates of polyalcohols such as those of glycol and of glycerol, ricinoleates of alcohols or of polyalcohols, such as cetyl ricinoleate, propylene glycol dicaprylate and diisopropyl adipate;
(2) fatty alcohols such as oleyl alcohol, linoleyl alcohol, linolenyl alcohol, isostearyl alcohol and octyldodecanol;
(3) silicone oils such as optionally functionalized linear polydiorganosiloxanes, cyclic polydiorganosiloxanes and in particular cyclotetra- and -pentadimethicones and organopolysiloxanes such as alkyl, alkoxy or phenyl dimethicones, and in particular phenyltrimethicone;
(4) fluoro oils such as perfluoroalkanes and perfluoropolyethers and partially fluorinated hydrocarbon-based oils.
B—The waxes in the fatty phase can be of mineral, fossil, animal, plant or synthetic origin or alternatively can be hydrogenated oils or fatty esters which are solid at 25° C.
Among the mineral waxes, mention may be made in particular of microcrystalline waxes, paraffin, petroleum jelly and ceresine.
Among the fossil waxes, mention may be made of ozocerite and montan wax.
Among the waxes of animal origin, mention may be made of beeswax, spermaceti, lanolin wax and derivatives obtained from lanolin such as lanolin alcohols, hydrogenated lanolin, hydroxylated lanolin, acetylated lanolin, lanolin fatty acids and acetylated lanolin alcohol.
Among the waxes of plant origin, mention may be made in particular of candelilla wax, carnauba wax, Japan wax and cocoa butter.
Among the synthetic waxes, mention may be made in particular of ethylene homopolymers and copolymers of ethylene and of a monomer corresponding to the formula:
CH2═CH—R3
in which:
R3 represents an alkyl radical containing from 1 to 30 carbon atoms or an aryl or aralkyl radical.
The alkyl radical of 1 to 30 carbon atoms is preferably a methyl, ethyl, propyl, isopropyl, butyl, decyl, dodecyl or octadecyl radical.
Waxes obtained by Fisher-Tropsch synthesis and silicone waxes can also be used.
Among the hydrogenated oils which are solid at 25° C., mention may be made in particular of hydrogenated castor oil, hydrogenated palm oil, hydrogenated tallow and hydrogenated coconut oil.
Among the fatty esters which are solid at 25° C., mention may be made in particular of propylene glycol monomyristate and myristyl myristate.
As waxes which can be used in the compositions according to the invention, mention may also be made of cetyl alcohol, stearyl alcohol, mono-, di- and triglycerides which are solid at 25° C., stearic monoethanolamide, colophony and its derivatives such as glycol abietate and glyceryl abietate, sucroglycerides and calcium, magnesium, zinc and aluminium oleates, myristates, lanolates, stearates and dihydroxystearates.
C—The pasty-type fatty substances can be of mineral, animal, plant or synthetic origin.
Among the pasty fatty substances, mention may be made in particular of synthetic esters such as arachidyl propionate, polyvinyl laurate, polyethylene waxes and organopolysiloxanes such as alkyldimethicones, alkoxydimethicones or dimethicone esters.
Needless to say, the anhydrous compositions according to the invention can also contain one or more conventional cosmetic or dermatological additives or adjuvants.
These anhydrous compositions can be in various forms such as, in particular, in the form of an oily gel, solid products, such as compacted or cast powders, or alternatively sticks such as, for example lipsticks.
When the compositions according to the invention are in the form of an oily gel, they generally contain, besides the constituents defined above, an oily gelling agent.
Among the oily gelling agents, mention may be made in particular of metal esters such as polyoxyaluminium stearate and aluminium or magnesium hydroxystearate, fatty acid esters of glycol, triglycerides, mixtures of fatty alcohols, cholesterol derivatives and in particular hydroxycholesterol, and clay minerals which swell in the presence of oil, and in particular those belonging to the montmorillonite group.
The oily gelling agents can be present in a very variable proportion depending on the desired texture of the compositions. However, in most cases, they are present in a proportion of from about 0.1 to about 30% by weight relative to the total weight of the composition. This range includes all specific values and subranges therebetween, such as 0.2, 0.5, 1, 2, 5, 10, 15, 20 and 25% by weight.
These anhydrous compositions according to the invention can be used in particular as care, cleansing or make-up products.
When they are present in the form of make-up products, they can be, in particular, foundations, mascaras, eyeliners, lipsticks, eyeshadows or blushers. These compositions are generally colored and, in this case, contain, as cosmetic adjuvants, dyes and/or pigments which are well known in the field of make-up products.
According to a second embodiment, the compositions according to the invention are stable dispersions in the form of a water-in-oil (W/O) or oil-in-water (O/W) emulsion, which consist essentially
(i) of a fatty phase in a proportion of from about 0.1 to about 50% by weight relative to the total weight of the composition, the said fatty phase containing at least one natural or recombinant spider silk protein, or an analog, in a proportion of from about 10−4 to about 30% by weight relative to the total weight of the emulsion,
(ii) of an aqueous phase in a proportion of from about 50 to about 98.9% by weight relative to the total weight of the emulsion, and
(iii) of at least one emulsifier in a proportion of from about 1 to about 10% by weight relative to the total weight of the emulsion.
The ranges specified for components (i)-(iii) above include all specific values and subranges therebetween.
These emulsions, which are in the form of creams, have a good film-forming nature and give a very satisfactory comfortable sensation after they have been applied. Such emulsions can be used as care, cleansing or make-up products.
When these compositions are skincare products, they can be, in particular, anti-wrinkle products for improving the appearance of the skin relief.
When these compositions are make-up products, they can be, in particular, foundations or mascaras containing, in this case, a certain proportion of pigments and/or dyes.
According to a third embodiment of the compositions according to the invention, they are in the form of products for the nails such as nail varnishes or nailcare products.
According to this embodiment, the compositions are preferably in the form of nail varnishes containing:
(i) a solvent system for varnishes, and
(ii) a film-forming substance.
The natural or recombinant spider silk protein or analog is, according to this embodiment, generally in a proportion of from 10−4 to 30% by weight relative to the total weight of the varnish.
According to this embodiment, the solvent system for the varnish is generally present in a proportion ranging from 55 to 90% by weight relative to the total weight of the varnish. This range includes all specific values and subranges therebetween, including 60, 65, 70, 75, 80, and 85% by weight.
Although the solvent system can be of the aqueous type, it preferably consists of a mixture of various volatile organic solvents, in order to obtain relatively short drying times.
Among these solvents, mention may be made of acetone, ethyl acetate, butyl acetate, 2-methoxyethyl acetate, methyl ethyl ketone, methyl isobutyl ketone, methyl acetate, amyl acetate and isopropyl acetate.
The solvent system can also comprise a diluent which is preferably a saturated, linear or branched hydrocarbon, such as hexane or octane, or alternatively an aromatic hydrocarbon such as toluene or xylene, in a proportion of from about 10 to about 35% by weight relative to the total weight of the varnish. This range includes all specific values and subranges therebetween, including 15, 20, 25 and 30% by weight. The solvent system can also include other volatile solvents such as ethanol, n-butanol, n-propanol, isopropanol or mixtures thereof.
Besides the spider silk protein, the composition according to the invention can also comprise a film-forming substance. This film-forming substance is generally present in a proportion of from about 5 to about 35% by weight relative to the total weight of the varnish. This range includes all specific values and subranges therebetween, including 10, 15, 20, 25, and 30% by weight. Among these film-forming substances, mention may be made of nitrocelluloses of the “RS” or “SS” type, in particular ¼ second RS type nitrocellulose, ¼ second RS type nitrocellulose, ½ second SS type nitrocellulose and ¾ second RS type nitrocellulose. Film-forming substances which can also be used according to the invention are polyvinyl derivatives such as polyvinyl butyrate.
Other film-forming substances which can be used according to the invention are cellulose derivatives other than nitrocellulose, acrylic polymers or copolymers, acrylic, styrene, acrylate-styrene and vinyl resins, vinyl copolymers, polyester polymers, arylsulphonamide resins and alkyde resins.
The varnishes according to the invention can also contain a plasticizer, which is generally present in a proportion of from about 5 to about 20% by weight relative to the total weight of the varnish. This range includes all specific values and subranges therebetween, including 10, 12, 15 and 18% by weight. The plasticizers allow the flexibility of the film to be adjusted without reducing its strength or its physical force. Among the plasticizers, mention may be made of: tricresyl phosphate, benzyl benzoate, tributyl phosphate, butyl acetyl ricinoleate, triethyl citrate, tributyl acetyl citrate, dibutyl phthalate and camphor.
The products for nails according to the invention can be either colorless or colored. When they are colored, they then contain pigments and/or dyes which are well known in the nail varnish sector.
According to a final specific embodiment of the cosmetic compositions according to the invention, they are hair compositions containing, in a suitable cosmetic vehicle, a natural or recombinant spider silk protein or an analog, in a proportion of from about 10−4 to about 30% by weight relative to the total weight of the composition.
These hair compositions can be aqueous, alcoholic or aqueous-alcoholic solutions, the alcohol preferably being ethanol or isopropanol, in a proportion of from about 60 to about 99.5% by weight relative to the total weight, for the aqueous-alcoholic solutions. This range includes all specific values and subranges therebetween, including 65, 70, 75, 80, 85, 90, 95 and 98% by weight.
These hair compositions can be in the form of lotions, aerosols, gels, mousses or fixing shampoos. They can be applied easily to the hair and form a hydrophobic film of low density at the surface of the hair, allowing satisfactory shaping of the hairstyle without making the hair feel sticky.
On account of the deposition of a thin hydrophobic film on the skin, the hair or the nails, the compositions according to the invention, as have just been described above, allow the vectorization of various active agents which are generally difficult to apply, such as vitamins, hormones, moisturizers and products which are active against skin or hair disorders.
The compositions according to the invention can also contain one or more conventional cosmetic adjuvants, such as antioxidants, preserving agents, fillers, surfactants, UVA and/or UVB sunscreens, fragrances, thickeners, wetting agents and anionic, nonionic or amphoteric polymers.
Among these adjuvants, the fillers are generally present, in the make-up or care products or in the dermatological products, in a maximum proportion of about 99.9% by weight relative to the total weight of the composition.
These fillers, in the form of very fine powders, can be of natural or synthetic origin. Among these, mention may be made in particular of:
a) mineral powders such as talc, kaolin, mica, silica, silicates, alumina, zeolites, hydroxyapatite, sericite, titanium dioxide, titanium micas, barium sulphate, bismuth oxychloride, boron nitride and metal powders such as aluminium powder;
b) plant powders such as corn starch, wheat starch or rice starch powders;
c) organic powders such as nylon powder, polyamide powder, polyester powder, polytetrafluoroethylene powder or polyethylene powder.
These various powders can also be coated, for example with metal salts of fatty acids, amino acids, lecithin, collagen, silicone compounds, fluoro compounds or with any common coating agent.
Besides the fillers, dyes and pigments also form part of the anhydrous make-up compositions or compositions in the form of dispersions. The compositions of the invention make it possible, by coating, to improve the water-resistance properties of these fragile compounds. The dyes and/or pigments are generally present in a maximum proportion of about 40% relative to the total weight of the composition.
In the lipsticks, the proportion of at least one dye and/or pigment is generally of from about 0.1 to about 15% by weight relative to the total weight of the lipstick.
Among the dyes in the make-up products, and in particular in the lipsticks, mention may be made of eosin derivatives such as D&C Red No. 21 and halogenated fluorescein derivatives such as D&C Red No. 27, D&C Red Orange No. 5 in combination with D&C Red No. 21 and D&C Orange No. 10.
Among the pigments, which may be inorganic or organic or alternatively metal lakes, mention may be made of titanium dioxide, zinc oxide, D&C Red No. 36 and D&C Orange No. 17, the calcium lakes of D&C Red Nos.7, 11, 31 and 34, the barium lake of D&C Red No. 12, the strontium lake D&C Red No. 13, the aluminium lakes of FD&C Yellow No. 5, of FD&C Yellow No. 6, of D&C Red No. 27, of D&C Red No. 21, of FD&C Blue No. 1, iron oxides, manganese violet, chromium oxide and ultramarine blue.
Among the nail varnish pigments the most commonly used, mention may be made of D&C Red Nos. 8, 10, 30 and 36, the barium lakes of D&C Red Nos. 6, 9 and 12, the calcium lakes of D&C Red Nos. 7, 11, 31 and 34, the strontium lake of D&C Red No. 30 and D&C Orange No. 17 and D&C Blue No. 6, these pigments generally being present in a proportion of between 0.01 and 2% relative to the total weight of the varnish composition.
The nail varnishes can also contain titanium dioxide in order to give the varnishes a certain amount of opacity, as well as certain iridescent substances such as guanine and thixotropic agents for preventing sedimentation of the pigments, such as modified montmorillonite clays such as, for example, Bentone 27, Bentone 34 or Bentone 38.
The composition of the invention may be used to apply the spider silk protein to the skin, nails, hair or mucous membranes, by contacting the composition with the skin, nails, hair or mucous membranes of a subject. Preferably, the inventive composition is used with human subjects.
Having generally described this invention, a further understanding can be obtained by reference to certain specific examples which are provided herein for purposes of illustration only and are not intended to be limiting unless otherwise specified.
The mixture is prepared cold using a turbomixer and the silk protein is incorporated after emulsification, by stirring for 5 minutes.
Obviously, additional modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.
This application is based on French Patent Application Serial No. 98-01614, filed on Feb. 11, 1998, and incorporated herein by reference in its entirety.
| Number | Date | Country | Kind |
|---|---|---|---|
| 98 01614 | Feb 1998 | FR | national |
This application is a Continuation of U.S. application Ser. No. 09/247,806, filed on Feb. 11, 1999, now U.S. Pat. No. 6,280,747.
| Number | Name | Date | Kind |
|---|---|---|---|
| 4839168 | Abe et al. | Jun 1989 | A |
| 5756677 | Lewis et al. | May 1998 | A |
| 5965146 | Franzke et al. | Oct 1999 | A |
| 6268169 | Fahnestock | Jul 2001 | B1 |
| 6280747 | Phillippe et al. | Aug 2001 | B1 |
| 6296860 | Hasegawa et al. | Oct 2001 | B1 |
| Number | Date | Country |
|---|---|---|
| 0 452 925 | Oct 1991 | EP |
| WO 9116351 | Oct 1991 | WO |
| WO 9708315 | Mar 1997 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 20020064539 A1 | May 2002 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 09247806 | Feb 1999 | US |
| Child | 09861597 | US |
