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A method of stabilizing a hydroquinone composition, comprising hydroquinone and one or more protected retinoids, comprising: maintaining pH of the composition at about 5.5 to about 8.0. Skin Contact Wash off immediately with plenty of water for at least 15 minutes. 0 7 r @ &. endstream endobj 382 0 obj << /Type /FontDescriptor /Ascent 891 /CapHeight 656 /Descent -216 /Flags 34 /FontBBox [ -558 -307 2034 1026 ] /FontName /BCGJCE+TimesNewRoman,Bold /ItalicAngle 0 /StemV 160 /XHeight 0 /FontFile2 389 0 R >> endobj 383 0 obj << /Type /Font /Subtype /TrueType /FirstChar 32 /LastChar 181 /Widths [ 250 0 0 0 0 0 0 278 333 333 500 0 250 333 250 278 500 500 500 500 500 500 500 500 500 500 333 333 0 570 0 0 0 722 667 722 722 667 611 778 778 389 500 778 667 944 722 778 611 778 722 556 667 722 722 1000 722 722 0 333 0 333 0 0 0 500 556 444 556 444 333 500 556 278 333 556 278 833 556 500 556 556 444 389 333 556 500 722 500 500 444 0 0 0 0 0 0 0 0 0 0 0 500 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 500 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 576 ] /Encoding /WinAnsiEncoding /BaseFont /BCGJCE+TimesNewRoman,Bold /FontDescriptor 382 0 R >> endobj 384 0 obj << /Type /FontDescriptor /Ascent 929 /CapHeight 0 /Descent -249 /Flags 32 /FontBBox [ -184 -249 1037 929 ] /FontName /BCGKAB+ImprintMT-Shadow /ItalicAngle 0 /StemV 0 /FontFile2 390 0 R >> endobj 385 0 obj << /Type /Font /Subtype /TrueType /FirstChar 32 /LastChar 122 /Widths [ 250 0 0 0 0 0 0 0 323 323 0 0 0 375 240 0 510 427 510 510 0 510 0 510 510 510 0 0 0 0 0 0 0 729 0 729 0 698 0 0 854 0 0 0 0 927 802 813 0 0 0 604 0 0 0 0 802 0 0 0 0 0 0 0 0 448 552 0 552 448 0 0 573 271 0 0 271 875 573 500 0 552 375 0 323 573 0 0 0 500 448 ] /Encoding /WinAnsiEncoding /BaseFont /BCGKAB+ImprintMT-Shadow /FontDescriptor 384 0 R >> endobj 386 0 obj << /N 3 /Alternate /DeviceRGB /Length 2575 /Filter /FlateDecode >> stream There are various other uses associated with its reducing power. Hydroquinone can be made through several routes. "F$H:R!zFQd?r9\A&GrQhE]a4zBgE#H *B=0HIpp0MxJ$D1D, VKYdE"EI2EBGt4MzNr!YK ?%_&#(0J:EAiQ(()WT6U@P+!~mDe!hh/']B/?a0nhF!X8kc&5S6lIa2cKMA!E#dV(kel }}Cq9 Other solubilities: soluble in alcohol and ether,slightly soluble in benzene,readily soluble in ethanol,acetone and methanol, Needle-like Crystals or Crystalline Powder. While patients suffer from pigmentation disorders, they may also suffer from other skin disorders and signs of aging, including but not limited to rough skin texture, mottled pigmentation, sallow complexion, lines and wrinkles. It is soluble in water. This composition is color stabilized and cosmetically elegant. NR 1L~tyj|ZZ3]jFlszH#bd]="nVj =rBF-=Y?Pe 3(\[3;wR-+7Fn ~pSQ(Rpiw^zYr''t@\vobE]u'C}io0q;^k5C@|zZNNA>,XOrztV;qO*w:MC$OI\_$Io 'v [ The drug is freely soluble in water and in alcohol. isosorbide, Ascorbic acid, i.e. Table I shows that at 5C, 4% hydroquinone compositions maintain their white color with the addition of at least about 0.01% sodium metabisulfite at the low pH ranges (from about 3.50 to about 5.50) and at least 0.05% sodium metabisulfite for pH about 6.0 to about 7.0. Production of Hydroquinone Industrial production of hydroquinone usually happens in two ways. If you are already a ChemPoint customer then sign up for access to our online ordering website. 20, 14331442 (1986), G. Wienke, J. Gmehling, Toxicol. ORIGINAL CODE: 0009012, Free format text: Van Haelst, P. Heesen, F. Van Der Wielen, H. Govers, Chemosphere 29, 16511660 (1994), Article [19][20], In 2006, the United States Food and Drug Administration revoked its previous approval of hydroquinone and proposed a ban on all over-the-counter preparations. Forms of retinoids have been developed wherein the retinoid is protected by a protective system. Anal. The aquatic toxicity of hydroquinone to fresh water fish, Daphnia, and algae was between 0.050- . Chemically, hydroquinone is designated as p-dihydroxybenzene; the empirical formula is C 6 H 6 O 2; molecular weight is 110.0. P, Kind code of ref document: Hydroquinone is a white, odorless, crystalline solid with an extremely low vapor pressure. Water Solubility 73000 mg/L at 25C 2.6B pH pKa 4.0 - 4.7 pK1 = 9.9 2.12 Oxidation:Reduction Potential +286 mV at 25C and pH 7 ENVIRONMENTAL FATE/BIODEGRADATION vz >I d50dwp?i4,H3. Toxicol. The FDA had classified hydroquinone in 1982 as a safe product - generally recognized as safe and effective (GRASE), however additional studies under the National Toxicology Program (NTP) were suggested in order to determine whether there is a risk to humans from the use of hydroquinone. AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE TR, Kind code of ref document: Some documentation and label information may refer to the legacy brand. Hydroquinone is highly susceptible to ring substitution by Friedel-Crafts reactions such as alkylation. Approved only for prescription use in the U.S. market.Ideal for creams, lotions, and gels for personal care ingredients, pharmaceutical chemical, pharmaceutical excipients, and skin care ingredients. Cookie Notice Hydroquinone is combustible when preheated. Polysorbate 20 0.5% 0.15g. Why we like it: This affordable cream contains 2 percent hydroquinone, sunscreen, and costs around five dollars. Solubility of Hydroquinone. 0.5% magnesium ascorbyl phosphate protected at pH 6.0-7.0, 1.0-1.5% at pH 5.5-7.0, and 2.0-3.0% at pH 3.5-7.0. C6H4O2) is formed. It is a reducing agent that is reversibly oxidized to semiquinone and quinone. 15, 188196 (1996), U. Domaska, Fluid Phase Equilib. LSPS, Laboratoire de Spectrochimie Et Pharmacologie Structurale, University of Tlemcen, BP 119, 13000, Tlemcen, Algeria, Department of Biology, University of Ghardaia, BP 455, 47000, Ghardaia, Algeria, You can also search for this author in On this Wikipedia the language links are at the top of the page across from the article title. 2017-02-16T09:38:58+01:00 Eastman Hydroquinone, USP, meets or exceeds the requirements of the United States Pharmacopoeia and is produced under conditions of current good manufacturing practices (cGMP). Environ. M1 and M2 microemulsions contain ethanol as co-surfactant. Some documentation and label information may refer to the legacy brand. ;O,1Y+%8#oKT^VWtew4>@V.SR :hmBZ>#ey!UC5! / /n Although about 0.01% sodium metabisulfite without magnesium ascorbyl phosphate may not color stabilize an about 4% hydroquinone composition, and about 0.5% magnesium ascorbyl phosphate without sodium metabisulfite may not either, the combination of sodium metabisulfite and magnesium ascorbyl phosphate in these percentages is effective to stabilize the color of the about 1% to about 12%, about 2% to about 10%, preferably about 2% to about 8% and more preferably about 3% to about 4% and most preferably 4% hydroquinone composition. Hydroquinone is combustible when preheated. Remove contact lenses, if present and easy to do. 2017-02-16T10:10:56+01:00 - 65.21.225.73. Chem. Res. 2017-02-16T10:10:56+01:00 Hydroquinone is extensively used as a photographic developer, an antioxidant, and a stabilizing agent for readily oxidizable polymers. Other antioxidants, for example cationic salts of acidic ascorbyl esters, most preferably magnesium ascorbyl phosphate, aminopropyl ascorbyl phosphate, and sodium ascorbyl phosphate, have not been utilized in combination with hydroquinone in view of the acidic pH, generally from about 3.4 to about 3.5, and the recommended pH range for magnesium ascorbyl phosphate is about 7.0 to 8.5. Hydroquinone undergoes oxidation under mild conditions to give benzoquinone, process which is reversible. fungichromin, Heterocyclic compounds having oxygen as the only ring hetero atom, e.g. Our team has been notified and we will fix it as soon as possible. The color stability of the hydroquinone composition is promoted by one or more antioxidants in the hydroquinone phase, preferably sulfite, including but not limited to sulfites, bisulfites, metabisulfites, their salts and their derivatives, most preferably sodium metabisulfite, and a cationic salt of acidic ascorbyl esters, most preferably magnesium ascorbyl phosphate. Additionally, the hydroquinone compositions frequently discolor over time and turn from a whitish color to a brown or even black. By rejecting non-essential cookies, Reddit may still use certain cookies to ensure the proper functionality of our platform. Hydroquinone IS a white crystalline substance when pure and is highly soluble in water. Have an order or account question? This is seen at about a pH of 3.50 with at least about 2.0% magnesium ascorbyl phosphate, and again at a pH of about 6.5 to about 7.0 with at least about 2.0% magnesium ascorbyl phosphate. 0000053439 00000 n Other aspects, advantages, and modifications are evident from a review of the following claims. For a shipping quote, check the box and the bottom and provide us your shipping information. AzA inhibits tyrosinase. Protected retinoid may be added to these compositions for additional skin benefit effects. Classical photo shops also sell hydroquinone. wG xR^[ochg`>b$*~ :Eb~,m,-,Y*6X[F=3Y~d tizf6~`{v.Ng#{}}jc1X6fm;'_9 r:8q:O:8uJqnv=MmR 4 You take the cream, put it in a container, take the powder measurement and add it. [24], Numerous studies have revealed that hydroquinone, if taken orally, can cause exogenous ochronosis, a disfiguring disease in which blue-black pigments are deposited onto the skin; however, skin preparations containing the ingredient are administered topically. vitamin C; Salts thereof, Medicinal preparations containing active ingredients not provided for in groups A61K31/00-A61K41/00, Mixtures of active ingredients without chemical characterisation, e.g. For more information, please see our It is highly soluble in water (70 g/litre at 25 C) and the log n-octanol/water partition coefficient is 0.59. 0000002221 00000 n This is a prescription-only ingredient in some countries, including the member states of the European Union under Directives 76/768/EEC:1976. Then take the water and put the measurement into the microwave until boiled. 76/768/EEC:1976 Council Directive 76/768/EEC of 27 July 1976 on the approximation of the laws of the Member States relating to cosmetic products: Organic Chemistry, Solomon and Fryhle, 10th edition, Wiley Publishing, 2010. &"oq YcbX.=a*t R@ A2, Designated state(s): The original Acros Organics product / item code or SKU reference has not changed as a part of the brand transition to Thermo Scientific Chemicals. Monobenzone is the monobenzyl ether of hydroquinone used medically for depigmentation. 0000004433 00000 n Hydroquinone is considered to be readily biodegrable and photodegradable. Determination and Correlation of Solubilities of Benzoic Acid, Salicylic Acid, Resorcinol and Hydroquinone in Water and in 1-Octanol at Temperatures from 297.25K to 334.45K. Phase A: Dissolve L-Ascorbic Acid in distilled water via agitation and gentle heating (warm, never hot or you will denature the ascorbic acid). The Boiling Point of hydroquinone is 287C Also, the Melting Point of hydroquinone is 172C. Examples of suitable methods of encapsulation include encapsulation by liposomes, wax, paraffin or any material or combination of materials which protect the retinoid from exposure to oxygen and inhibit oxidation of the retinoid from oxidation. Tests, which results are detailed in the following two tables, are performed at 5C and 40C for certain percentages of magnesium ascorbyl phosphate at specific pHs. Without being limited to the mechanism of this discoloration, it is believed that the discoloration may be caused at least in part by oxidation of the hydroquinone. 388, 7381 (2010), H. Li, G. Hu, F. Guo, L. Zhao, J. Zhu, Y. Zhang, Can. Free format text: Tests, which results are detailed in the following two tables, are performed to show how well sodium metabisulfite ("SMBS") stabilizes color at each pH at 5C and 40C in 4% hydroquinone ("HQ") compositions. In the environment, hydroquinone showed increased toxicity for aquatic organisms, being less harmful for bacteria and fungi. Thermodyn. When the contents of the reservoir are forced into the reaction chamber, the catalases and peroxidases rapidly break down the hydrogen peroxide and catalyze the oxidation of the hydroquinones into p-quinones. Get medical attention. 0000003430 00000 n While the hydroquinone is effective for the pigmentation disorder treatment, retinoid is used for its skin treatment benefits. I did that by using 1 cup of cream, 4tbsp of hydroquinone and 4tbsp of water or solvent. By accepting all cookies, you agree to our use of cookies to deliver and maintain our services and site, improve the quality of Reddit, personalize Reddit content and advertising, and measure the effectiveness of advertising. 1 Solubility data for compounds that ordinarily are liquids at 25 are expressed in terms of the ratio of the volume of solute to the volume of solvent; i.e., 1 mL dissolved in mL of solvent. The present invention is not to be limited by any mechanism described in the specification, because it is defined by the claims. 0000005089 00000 n : Metabolism and disposition of hydroquinone in Fischer 344 rats after oral or dermal administration. 0000003660 00000 n Conversion factors (at 25 oc and normal atmospheric pressure) 1 ppm = 4.5 mg!m 3 All information collection is solely used to support ChemPoint customers service communications. A common route involves hydroxylation of phenol. GHS H Statement: Causes serious eye damage.Suspected of causing genetic defects.May cause an allergic skin reaction.Suspected of causing cancer.Harmful if swallowed.Very toxic to aquatic life. Glycerol derivatives solubilise natural, hydrophilic antioxidants in biofuels. It has a white-solid appearance. By acting as a free radical scavenger, hydroquinone serves to prolong the shelflife of light-sensitive resins such as preceramic polymers.[18]. Toughness of the polymer increases due to the presence of flexible units in the backbone such as long chain diols (e.g., diethylene glycol, dipropylene glycol, triethylene glycol) or long chain saturated acids (e.g., adipic . We will respond to you shortly. It is a reducmg agent that is reversibly oxidized to semiquinone and quinone. Then take the water and put the measurement into the microwave until boiled. 77, No. Other properties of hydroquinone are given in Table 1. Since hydroquinone has a tendency to discolor through oxidation, these antioxidants are used because they have greater tendencies to oxidize than hydroquinone. [Na+].OC(=O)CC(O)(CC([O-])=O)C(O)=O.OC(=O)CC(O)(CC([O-])=O)C(O)=O, SPECIFIC USE OF COSMETICS OR SIMILAR TOILET PREPARATIONS, Preparations for care of the skin for chemically bleaching or whitening the skin, PREPARATIONS FOR MEDICAL, DENTAL, OR TOILET PURPOSES, Medicinal preparations containing organic active ingredients, Acids; Anhydrides, halides or salts thereof, e.g. Stir until uniform. The solubility in water is 6.72g/L. It is found in wheat, rye, and barley.It is a precursor to diverse industrial products including polymers and plasticizers, as well as being a component of a number of hair and skin conditioners. Keywords: D-170D; D-170; D170D; D170 Created Date Read our Privacy Notice. This Thermo Scientific Chemicals brand product was originally part of the Acros Organics product portfolio. 420, 2429 (2016), W. E. Acree Jr, Thermochim Acta 189, 3756 (1991), F. L. Nordstrm, . C. Rasmuson, J. Chem. With an account you can check out faster, view your online order history and access your shopping bag or saved items from any device. Most preferably, when both a water-soluble antioxidant, preferably sulfite, including but not limited to sulfites, bisulfites, metabisulfites, their salts and their derivatives, most preferably sodium metabisulfite, and a cationic salt of acidic ascorbyl esters, most preferably magnesium ascorbyl phosphate, are present, the color of the hydroquinone composition is stabilized in the neutral pH range, preferably for greater than about six months, more preferably for greater than about twelve months and most preferably for greater than about eighteen months. Recent pieces of . Methylaminophenol, used in photography, is produced in this way:[8]. The obtained results show that the solubility of benzoic acid in water is greater than that of salicylic acid, but in the case of the two isomers of dihydroxybenzene, the solubility of resorcinol is approximately 100 times that of hydroquinone. Therefore, the solubility values of hydroquinone in different solvents are required; however, the data availability in the literature is poor.3-7 In this work, the solubility data of hydroquinone in water, methanol, ethanol, 2-propanol, ethyl acetate, butyl acetate, and acetic acid from 276.65 K to 345.10 K under atmospheric pressure were . Then add it to the ingredients. Provided by the Springer Nature SharedIt content-sharing initiative, Over 10 million scientific documents at your fingertips, Not logged in 2y.-;!KZ ^i"L0- @8(r;q7Ly&Qq4j|9 The protective system can be an entrapment system, a single or multi- laminar system, such as by the formation of vesicles such as a liposome or by utilizing wax, paraffin, silicone, polyethylene, or any material or system which protects the retinoid from oxidation. . Boucif Belhachemi. An acceptable carrier also possesses suitable aesthetic and cosmetic qualities and may include emollients, conditioners and the like. I can't use water because I cannot dissolve enough Hydroquinone into it to reach the desired concentration. [23] This conclusion was reached based on the extent of absorption in humans and the incidence of neoplasms in rats in several studies where adult rats were found to have increased rates of tumours, including thyroid follicular cell hyperplasias, anisokaryosis (variation in nuclei sizes), mononuclear cell leukemia, hepatocellular adenomas and renal tubule cell adenomas. application/pdf Also in this embodiment is a cationic salt of acidic ascorbyl esters, which further helps to maintain the acceptable color desired in the hydroquinone composition. As utilized herein, the inhibition of the retinoid oxidation should be sufficient to prohibit browning of the composition for its shelf life, preferably greater than about six months, more preferably greater than about twelve months, and most preferably greater than about eighteen months. PubMedGoogle Scholar. If you have any specific questions, please include them in the comments section. Retinoid compositions, in particular retinoic acid, retinal, and their derivatives, isomers and analogs (such as adapalene, tazarotene and isotretoin) are known to be effective in improving rough skin texture, mottled pigmentation, sallow complexion, lines and wrinkles. Chim. Hydroquinone is 1,4-benzenediol. fungichromin having five-membered rings with one oxygen as the only ring hetero atom, e.g. The obtained results show that the . 58 / Monday, March 26, 2012 / Rules and Regulations 10/31/2017 EN (English US) 6/8 12.3. So, does anybody know of another solvent I could use that has a higher . The Density of hydroquinone is . Privacy Policy. However, a problem with a formulation containing both retinoids and hydroquinone has been their incompatible pH ranges. Johnson & Johnson Consumer Products, Inc. Johnson & Johnson Consumer Companies, Inc. AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE TR, STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN, Color Stability of 4% HQ Compositions with varying pH and % Sodium Metabisulfite at 5C and 40C, Color Stability of 4% HQ Compositions with varying pH and % Magnesium Ascorbyl Phosphate at 5C and 40C, Polyacrylamide (and) C 13-14 isoparaffin (and) laureth-7, Water, Soybean (Glycine Soja) Oil, Carnauba (Copemicia Cerifera), wax, tocopherol, retinol, Ceteareth-20, Water, Soybean (Glycine Soja) Oil, Carnauba (Copernicia Cerifera), wax, tocopherol, retinol, Ceteareth-20, Compositions for the treatment of pigmentation disorders and methods for their manufacture, Stabilization composition including hydroquinone or derivative thereof, Stabilized retinol for cosmetic dermatological, and pharmaceutical compositions, and use thereof, Depigmenting composition for the skin comprising adapalene and at least one depigmenting agent, Depigmenting composition for the skin, use of a depigmenting composition for the skin, cosmetic use of the same and method for non-therapeutic cosmetic treatment, Cosmetic designs and products using intronic RNA, Holistic composition and method for reducing skin pigmentation, Topical compositions and methods of manufacturing them in specifically treated steel vessels, System for improved percutaneous absorption of skin benefiting agents, Discontinuous surface coating for particles, Method of treating skin requiring chemical peel procedure, Method of treating skin needing hyaluronic acid treatment, Method of treating skin having incision from surgical procedures, Method of treating skin requiring hair removal procedure, Method of treating skin requiring Intense Pulse Light (IPL) procedure, Method of treating skin subject to or affected by aesthetic surgical procedures, Method of treating skin needing ablative treatment, Method of treating skin requiring radiofrequency procedure, Method of treating skin requiring non-ablative procedure, Method of treating skin requiring fractional resurfacing treatment, Method of treating skin needing botulinum toxin type a treatment, Method of treating skin requiring microdermabrasion, Method of treating skin needing collagen treatment, Method of treating skin requiring skin cancer treatment, Methods of treating skin to enhance therapeutic treatment thereof, Ras mutation and compositions and methods related thereto, Compositions, kits and regimens for the treatment of skin, especially dcolletage, Calcium sequestration compositions and methods of treating skin pigmentation disorders and conditions. HYdroquinone can be found in various skin care products. Using a laser-monitoring observation technique, the solubility of hydroquinone in water, methanol, ethanol, 2-propanol, ethyl acetate, butyl acetate, and acetic acid were measured at temperatures ranging from 276.65 K to 345.10 K under the atmospheric pressure. At 40C, 4% hydroquinone compositions are more likely to excessively discolor and magnesium ascorbyl phosphate helps to stabilize the color, by preventing the brownish black discoloration and maintaining an amber color. International Journal of Thermophysics This website uses cookies. A3, Free format text: Some hydroquinone compositions include antioxidants, such as ascorbyl palmitate. ADS The amount of crosslinking was controlled by the reaction conditions, including temperature, reaction time, and . HyTSwoc [5laQIBHADED2mtFOE.c}088GNg9w '0 Jb The solubility in water is 6.72g/L. Phase B: Dissolve the ferulic acid in the glycerin - some "spirited" stirring may be necessary. Get medical attention. If youd like my help or recipes for this bleaching cream please contact me on Instagram @kaylinell and @kay.linell or Facebook at kay linell. Continue rinsing.IF SWALLOWED: Call a POISON CENTER or doctor/physician if you feel unwell.Avoid release to the environment.WARNING: The information provided on this web site was developed in compliance with European Union (EU) regulations and is correct to the best of our knowledge, information and belief at the date of its publication. Antioxidants in the hydroquinone phase and inorganic or amino acyl cationic salts of acidic ascorbyl esters, preferably sodium metabisulfite and magnesium ascorbyl phosphate respectively, are effective in stabilizing such hydroquinone compositions, which are used in treatment of pigmentation disorders. Dietland Muller-Schwarze, 2003, page 43 (, National Institute for Occupational Safety and Health, Additive manufacturing of ceramics from preceramic polymers, http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=CELEX:31976L0768:EN:HTML, "Clear N Smooth Skin Toning Cream recalled", Skin Bleaching Drug Products for Over-the-Counter Product Use; Proposed Rule, "About the Center for Drug Evaluation and Research - Hydroquinone Studies Under The National Toxicology Program (NTP)", Campaign For Safe Cosmetics - Hydroquinone, "Skin lightening preparations and the hydroquinone controversy", https://en.wikipedia.org/w/index.php?title=Hydroquinone&oldid=1136453324, Wikipedia articles needing page number citations from October 2016, Pages using collapsible list with both background and text-align in titlestyle, Articles containing unverified chemical infoboxes, Creative Commons Attribution-ShareAlike License 3.0, The most widely used route is similar to the, A potentially significant synthesis of hydroquinone from, Hydroquinone was first obtained in 1820 by the French chemists, Pelletier and Caventou (1820) "Recherches chimiques sur les quinquinas" (Chemical investigations of quinquinas [i.e., the bark of various, This page was last edited on 30 January 2023, at 11:09. Compositions according to this invention may include additives or components to enhance the skin penetration of its ingredients. 109. Google Scholar, W. J. Weber Jr, Y.-P. Chin, C. P. Rice, Water Res. According to the polar paradox theory, this should lead to a dissolution of . ORIGINAL CODE: 0009013, Ref document number: sulfur acids, imidic, hydrazonic, hydroximic acids, Carboxylic acids, e.g. Chem. Ferulic acid 0.5% 0.15g. Part of Springer Nature. 4]DYR@'c This page was last modified on 19 June 2019, at 20:05. Eng. [34], It is also one of the chemical compounds found in castoreum. It is a major component in most black and white photographic developers for film and paper where, with the compound metol, it reduces silver halides to elemental silver. The natural pH for conventional hydroquinone compositions is acidic, generally less than about 4 even though this is harsh to the skin and to other components of the product. It is understood that while the invention has been described in conjunction with the detailed description thereof, that the foregoing description is intended to illustrate and not limit the scope of the invention, which is defined by the scope of the appended claims. Hydroquinone is an aromatic organic compound which is currently used in two main sectors: . I made my own hydroquinone 4% and added it to my cream.