Abstract:
This invention is a topical tyrosinase inhibiting combination using alpha arbutin and bearberry extract, in synergism, for the purpose of skin lightening. The active admixture is a dermatological serum comprised of alpha arbutin, octyl stearate and polyolprepolymer-2, introduced onto the human skin in liposome form for ultra-deep penetration.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is a divisional application of application Ser. No. 11/060,348, filed Feb. 18, 2005, and entitled “TOPICAL COSMETIC COMPOSITIONS CONTAINING ALPHA ARBUTIN.” 
     
    
     FIELD OF THE INVENTION  
       [0002]     The invention relates to topical cosmetic compositions, in particular, human skin lightening compositions, comprising admixtures of alpha arbutin and bearberry extract used for topical application.  
       BACKGROUND OF THE INVENTION  
       [0003]     The present invention is a novel topically applied dermocosmetic composition comprising certain admixtures of the glucoside alpha arbutin and the botanical extract bearberry to be used in skin lightening.  
         [0004]     Certain humans at different phases of their lifetime, and from different parts of the world, and in differing phases of their health develop excess melanin and/or colored blemishes on the skin. This excess melanin can occur on any part of the human body, but most commonly appear on the face and back of the hands. These dark spots are caused by high levels of melanin in the keratinocytes located in the top layer of the epidermis.  
         [0005]     Melanocytes are located deep in the stratum granulosum, produce melanin, and through an unknown mechanism the melanin rises through about 100 cell layers to the surface where they exist as unsightly dark spots.  
         [0006]     Biochemically, the process is: 
        Tyrosine amino acid (from diet) goes to Dopa; Dopa goes to Dopaquinone; Dopaquinone goes to Dopachrome; Dopachrome goes to Melanin.        
 
         [0008]     Melanin deposits are seen as the dark spots on the surface of the human skin. They may be called “sun spots” or “age spots” or “liver spots.” 
       Tyrosinase Inhibition  
       [0009]     Tyrosinase is the enzyme which catalyzes the amino acid tyrosine into dopa (dihydroxyphenylamine), as well as the change from dopa into dopaquinone. Skin lightening products are designed to inhibit the action of tyrosinase.  
         [0010]     Hydroquinone is the most common inhibitor of the enzyme tyrosinase. Hydroquinone is OTC Monographed (United States Food and Drug Administration 21 CPR) as a Category I skin lightener/skin bleacher/skin whitener in the concentration limits of 1.5-2.0% by weight. Used in this concentration, no clinical trials and no pre-market clearance are necessary in the USA marketplace. Used in higher concentrations than 2% by weight, hydroquinone compositions legally require a prescription in the USA marketplace. Production of hydroquinone preparations over 2% by weight requires an approved ANDA (Approved New Drug Application-21 CFR 394). However, hydroquinone is an irritant to some individuals, particularly those with light skin types, and may be cytotoxic to melanocytes. It is not legally marketed in Japan, the Union of South Africa and several other countries at present, and several other countries are considering denying legal marketing clearance because of concern about long term toxicity. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0011]     Alpha arbutin avoids the direct toxicity of hydroquinone and the indirect toxicity of beta arbutin which easily hydrolyses to hydroquinone. Alpha arbutin acts more slowly than hydroquinone, taking a slightly longer time to meet the customer&#39;s skin lightening objectives when used alone. This invention involves the use of alpha arbutin and bearberry extract in combination. This combination is synergistic in skin whitening effectiveness, as the bearberry extract serves to potentiate the alpha arbutin. Moreover, the alpha-glucosidic bond has a higher stability than the beta glucosidic bond, giving greater stability and greater effectiveness than beta arbutin.  
       Advanced Liposome Delivery System  
       [0012]     This patent teaches that the use of polyolprepolymer-2 in an admixture with alpha arbutin/bearberry extract. This is in order to both extend the stability of the alpha arbutin to avoid possible deleterious effects due to oxidation related to the oxygen in the atmosphere as well as that caused by cell respiration potentiators found in epidermal respiration.  
         [0013]     This invention teaches that the use of polyolprepolymer-2, when admixed with the serum comprised of alpha arbutin and octyl stearate, can be administered into the human skin using a liposome advanced delivery mechanism. Liposomes can easily be formed by those familiar in the art of liposome manufacture, using either preformed empty liposomes (Brookosomes MT) or by using ultra high pressure (20,000-40,000 PSI) in the usual microfluidizer.  
       SUMMARY OF THE INVENTION  
       [0014]     In the preferred embodiment of this invention, a serum comprised of alpha arbutin 0.01-6.0% w/w (more preferably 1-4% w/w) plus bearberry extract 0.01% w/w (most preferably 1-3% w/w) is admixed with polyolprepolymer-2 0.5-10% w/w (most preferably 1-3% w/w), and this combination is further prepared into a liposome form with the use of lecithin, water and ultra high pressure microfluidizer. The liposome formation is well known to those familiar in the use of the ultra high PSI providing microfluidizer.  
         [0015]     This invention additionally teaches the serum-liposome admixture being further admixed into a gel or cream carrier as an advanced delivery system used in cosmetic, esthetician, spa and dermatology office settings.  
         [0016]     Additionally, this stabilized alpha arbutin-polyolprepolymer 2-liposome concentrate, which has been diluted into a cosmetic carrier, is potentiated with the admixture of the proven botanical extract, bearberry extract. Moreover, additional nutrients including Vitamins A, B, C, E and Panthenol may be included in the liposome addition process.  
         [0017]     Clinical testing using before and after microscopic videos establishes that this potentiation takes place in clinical, human usage.  
       Composition  
       [0018]     The most preferable embodiment composition is as follows:  
                                       Part   Ingredient INCI   Percentage by weight                   A   Aqua (water)   qs 100%       A   Methylparaben   0.23       A   Glycerin   4       A   EDTA disodium   0.12       B   Cetearyl alcohol, ceteareth 20   9       B   Propylparaben   0.12       B   Cetyl palmitate   2       B   Dimethicone 50   1       B   Steareth-20   1       C   Alpha arbutin   3       C   Octyl stearate   7       C   Polyolprepolymer-2   2       D   Lecithin, Water   1           (Brookosomes MT)           Lecithin, Vitamins A, C &amp; E   1       E   Bearberry Extract   1           (Gatulin-Gattefosse)                  
 
       Manufacturing Procedure  
       [0019]     Manufacturing procedure for the most preferred embodiment is as follows:  
         [0020]     The hot part B (80 degrees C.) is mixed into the hot part A (80 degrees C.) to form the conventional emulsion core. Continue mixing and cooling.  
         [0021]     Part C is prepared in a separate jacketed kettle at about 45 degrees C.  
         [0022]     As part AB is mixing and cooling to about 45 degrees C., slowly add part C with mixing, then slowly add part D (all liposomes).  
         [0023]     Continue to mix and cool part ABCD to about 35 degrees C. Slowly add with high agitation the Part E. Continue to mix and cool to 25 degrees C.