Topical compositions and methods of manufacturing them in specifically treated steel vessels

Abstract

Stable hydroquinone compositions that are useful for skin care and can have a shelf life of up to three years are prepared in a tank made from a material that does not release metallic ions into the composition.

1 .- 25 . (canceled) 
     
     
         26 . An emulsion comprising: hydroquinone; a preservative; a chelating agent; an emulsifier; a humectant; a pH adjuster; an antioxidant; an emollient; a reducing agent and water, wherein the emulsion is made in a passivated tank, and the discoloration of the emulsion is slowed compared to the discoloration of the same emulsion that has not been prepared in the passivated tank. 
     
     
         27 . The emulsion according to  claim 26 , wherein the composition maintains an acceptable color for three years, and wherein the acceptable color is a color lighter than brown. 
     
     
         28 . The emulsion according to  claim 26 , wherein the preservative is selected from benzoic acid, benzyl alcohol, butylparaben, diazolidinyl urea, 2,3-Imidazolidinedione, isopropylparaben, isobutylparaben, methylparaben, propylparaben, sodium butylparaben, sorbic acid, or combinations thereof. 
     
     
         29 . The emulsion according to  claim 26 , wherein the chelating agent is selected from citric acid, edetate disodium, ethylenediaminetetraacetic acid, etidronic acid sodium dihydroxyethylglycinate, nitrilotriacetic acid, or combinations thereof. 
     
     
         30 . The emulsion according to  claim 26 , wherein the emulsifier is selected from cetearyl alcohol, ethoxylated fatty alcohols, PEG-1000 monocetyl ether, alkyl trimethyl ammonium bromide, polyol ester glycerol monostearate, potassium stearate, sodium lauryl sulfate, sodium cetearyl sulfate, saponins, or combinations thereof. 
     
     
         31 . The emulsion according to  claim 26 , wherein the humectant is selected from glycerin, diglycerin, triglycerin, polyglycerin, polypropylene glycol, polyethylene glycol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, hexylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, ethylene glycol monoalkyl ether, diethylene glycol monoalkyl ether, glucose, maltose, sucrose, lactose, xylitose, xylitol, sorbitol, mannitol, maltitol, panthenol, pentaerythritol, hyaluronic acid, or combinations thereof. 
     
     
         32 . The emulsion according to  claim 26 , wherein the pH adjuster is selected from citric acid, phosphoric acid, lactic acid, glycolic acid, or combinations thereof. 
     
     
         33 . The emulsion according to  claim 26 , wherein the antioxidant is selected from ascorbyl palmitate, 2,6 ditertiarybutyl-4-methyl phenol, butylated hydroxyanisole, tocopherol, tocopheryl acetate, propyl gallate, or combinations thereof. 
     
     
         34 . The emulsion according to  claim 26 , wherein the emollient is selected from cetyl alcohol, stearyl alcohol, liquid hydrocarbon oil, liquid natural oil, liquid fatty alcohol, liquid fatty acid, liquid fatty acid ester, liquid silicone oil, paste wax, or combinations thereof. 
     
     
         35 . The emulsion according to  claim 34 , wherein the emollient comprises a liquid hydrocarbon oil selected from squalane, liquid mineral oil, liquid polybutene, or combinations thereof. 
     
     
         36 . The emulsion according to  claim 34 , wherein the emollient comprises a liquid natural oil selected from almond oil, olive oil, sesame oil, safflower oil, avocado oil, cottonseed oil, jojoba oil, castor oil, soybean oil, palm kernel oil, coconut oil, hydrogenated vegetable oil, mink oil, egg yolk oil, or combinations thereof. 
     
     
         37 . The emulsion according to  claim 34 , wherein the emollient comprises a liquid fatty alcohol selected from isostearyl alcohol, lanolin alcohol, oleyl alcohol, hexadecyl alcohol, octyldodecanol alcohol, linoleyl alcohol, linolenyl alcohol, lauryl alcohol, arachidyl alcohol, or combinations thereof. 
     
     
         38 . The emulsion according to  claim 34 , wherein the emollient comprises a liquid fatty acid selected from caprylic acid, isostearic acid, linoleic acid, ricinoleic acid, oleic acid, or combinations thereof. 
     
     
         39 . The emulsion according to  claim 34 , wherein the emollient comprises a liquid fatty acid ester selected from cetyl octanoate, glyceryl trioctanoate, isopropyl linoleate, isopropyl myristate, isopropyl oleate, ethyllaurate, ethyl linoleate, octyl dodecyl myristate, octyl palmitate, octyl isopelargonate, octyl dodecyllactate, isotridecyl isononanoate, oleyl oleate, isostearyl myristate, neopentyl glycol dioctanoate, and di(capryl/capric acid) propylene glycol, or combinations thereof. 
     
     
         40 . The emulsion according to  claim 26 , wherein the reducing agent is selected from ascorbic acid, propyl gallate, sodium metabisulfite, or combination thereof. 
     
     
         41 . The emulsion according to  claim 26 , wherein the emulsion has a viscosity of from about 1,000 to about 50,000 centipoise. 
     
     
         42 . The emulsion according to  claim 26 , further comprising a sunscreen. 
     
     
         43 . The emulsion according to  claim 26 , wherein the emulsion is a lotion. 
     
     
         44 . The emulsion according to  claim 26 , wherein the passivated tank is prepared by contacting the tank with a chelating acid prior to preparing the emulsion. 
     
     
         45 . The emulsion according to  claim 44 , wherein the tank is made of a material that does not release metallic ions. 
     
     
         46 . The emulsion according to  claim 45 , wherein the tank is made of stainless steel. 
     
     
         47 . The emulsion according to  claim 44 , wherein the chelating acid is citric acid.