Do not put this product in the microwave. Calorim. 12.4. Lastly, I'd like to add benzoic acid for preservation purposes. Hydroquinone is a white crystalline solid, poorly soluble in water, but more soluble in organic solvents. Thank you for your inquiry and interest in ChemPoint. 420, 2429 (2016), W. E. Acree Jr, Thermochim Acta 189, 3756 (1991), F. L. Nordstrm, . C. Rasmuson, J. Chem. It is not to be considered as either a warranty or quality specification. According to the polar paradox theory, this should lead to a dissolution of . 2017-02-16T10:10:56+01:00 Our team has been notified and we will fix it as soon as possible. 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. I understand the concentrations are high but I have used them before, its just too expensive to keep buying from a compounding pharmacy. [22] The FDA stated that hydroquinone cannot be ruled out as a potential carcinogen. Boucif Belhachemi. [32], Hydroquinone is thought to be the active toxin in Agaricus hondensis mushrooms. 114, 175188 (1996), I. Hahnenkamp, G. Graubner, J. Gmehling, Int. Classical photo shops also sell hydroquinone. uuid:3780f5dc-b322-4e29-9b1d-4c4d10b1e282 Substituted derivatives of this parent compound are also referred to as hydroquinones. HlRMo0WB:NnVCnE4(i0 (1* )@NzHR!>i;8XaXnsO0LNT0l$B%"NAb0I9V *6/-\vn0W"fKF:AAgl:psRZ?k`&eB IUQ0ET;W#vL=@XwRG{-LHlTz]^s%OB(GF 11'I The protective system can be an entrapment system, a single or multi-laminar system, such as by formation of vesicle, such as a liposome, or by utilizing wax, paraffin, silicone, polyethylene or any material or system which protects the retinoid from oxidation. However, these hydroquinone-containing compositions were in the acidic pH range and did not contain cationic salts of acidic ascorbyl esters, such as magnesium ascorbyl phosphate. Gravimetric method is used to measured hydroquinone solubility in water, ethanol and in water+ethanol binary mixtures at temperatures (293.15, 295.15, 298.15, 300.15, 303.15, 305.15, 308.15, 310.15 and 313.15)K. Mole fractions solubility of hydroquinone are correlated with temperature by using the Apelblat equation. The obtained results show that the . Gerhard Franz, Roger A. Sheldon "Oxidation" in. 0000005089 00000 n It would be desirable to combine the pigmentation disorder treatment with this skin benefit ingredient in one composition. and our Eye Contact Rinse immediately with plenty of water, also under the eyelids, for at least 15 minutes. D-170D Solubility of EASTMAN Hydroquinone and Derivatives Subject: Hydroquinone and hydroquinone derivatives listed in this publication are used as intermediates for manufacturing a variety of products and as polymerization inhibitors for vinyl monomers and unsaturated polyester resins. ChemPoint will not under any circumstances release personal user information to individuals or companies. Then take the water and put the measurement into the microwave until boiled. The information given is designed only as a guide for safe handling and use. As a polymerisation inhibitor, exploiting its antioxidant properties, hydroquinone prevents polymerization of acrylic acid, methyl methacrylate, cyanoacrylate, and other monomers that are susceptible to radical-initiated polymerization. The drug is freely soluble in water and in alcohol. Compositions according to this invention may include dermatologically acceptable carriers. [17], An important reaction is the conversion of hydroquinone to the mono- and diamine derivatives. Hi, let us know if you have any questions as you visit our website. Calorim. J. Eastman has active ingredients, thickeners, plasticizers, film formers, and more for your personal care formulations. Canon This is a prescription-only ingredient in some countries, including the member states of the European Union under Directives 76/768/EEC:1976. 88, 161164 (2010), J. Delgado, Int. InChI=1S/C6H6O2/c7-5-1-2-6(8)4-3-5/h1-4,7-8H, InChI=1/C6H6O2/c7-5-1-2-6(8)4-3-5/h1-4,7-8H, Except where otherwise noted, data are given for materials in their. 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. Preferably, the protected retinoid, in particular retinoic acid, retinal, and their derivatives, isomers and analogs (such as adapalene, tazarotene and isotretoin), is in the form of small beads or spheres suitable for incorporation into a topical composition. COMMON BRAND NAME (S): Aclaro, Aclaro PD, Alera, Alphaquin HP, Alustra, Claripel, Complex B . 0000005757 00000 n Other adverse effects The correlation coefficient is greater than 0.9937 for one of these two equations for the binary studied systems where the solvent is either water or 1-octanol. 1401417, Country of ref document: Hydroquinone, like phenols are very weak acids and can be deprotonated. Human exposure to hydroquinone can occur by dietary, occupational, and environmental sources. On this Wikipedia the language links are at the top of the page across from the article title. Some documentation and label information may refer to the legacy brand. Eastman Hydroquinone, USP Grade is for skin-lightening products to address hyperpigmentation. While the hydroquinone is effective for the pigmentation disorder treatment, retinoid is used for its skin treatment benefits. The solubility was increased by addition of ethanol, reached a maximum . The preferred protected retinoid is in the form of small beads or vesicles which are of a form that can be adjusted to be incorporated into varied topical compositions. This Thermo Scientific Chemicals brand product was originally part of the Acros Organics product portfolio. Glycerol derivatives solubilise natural, hydrophilic antioxidants in biofuels. I'm using it for spot treatment of some hyper pigmentation (less than 1% of my body). Thermodyn. Have an order or account question? "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 Hydroquinone compositions are effective but have some undesirable side effects. 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. Some documentation and label information may refer to the legacy brand. Adobe Acrobat 10.1.6 Paper Capture Plug-in The combined nearly ideal binary solvent (NIBS)-Redlich-Kister equation is . Eng. [Na+].OC[C@H](O)[C@H]1OC([O-])=C(OP([O-])([O-])=O)C1=O, N1=CC(C(=O)OCC)=CC=C1C#CC1=CC=C(SCCC2(C)C)C2=C1, C1=C(C(O)=O)C=CC2=CC(C3=CC=C(C(=C3)C34CC5CC(CC(C5)C3)C4)OC)=CC=C21, CC(=O)OC1=C(C)C(C)=C2O[C@@](CCC[C@H](C)CCC[C@H](C)CCCC(C)C)(C)CCC2=C1C, disodium;2-[2-[carboxylatomethyl(carboxymethyl)amino]ethyl-(carboxymethyl)amino]acetate, [Na+]. They may also include ingredients with other therapeutic actions, such as anti-inflammatories, antibiotics, exfoliants and peels. Rev. Fill out the form below, and we will send you the document as soon as we can! Get medical attention. Best Budget Hydroquinone Cream Ambi Skincare Fade Cream (56g/2oz) View on Amazon. If breathing is difficult, give oxygen. J. Pharm. : Metabolism and disposition of hydroquinone in Fischer 344 rats after oral or dermal administration. ORIGINAL CODE: 0009013, Ref document number: For more information, please see our The solubilities of benzoic acid, salicylic acid, resorcinol and hydroquinone in water and in 1-octanol were measured by the dynamic method which is also called the synthetic method from 297.25 K to 334.45 K. Using differential scanning calorimetry (DSC Q2000 and SDT Q600), the melting temperature and the enthalpy of fusion of these solutes were determined. Bioaccumulative potential Hydroquinone (123 -31 -9) Bioaccumulative potential Not established. It exerts a depigmenting effect on skin of mammals by increasing the excretion of melanin from the melanocytes. The solubility in water is 6.72g/L. Methods and products for nucleic acid production and delivery, Nucleic acid product and its administration method, Nucleic acid product and method of administration thereof, Compositions and systems for the treatment of hyperpigmentation, Methods for prevention of post-inflammatory hyperpigmentation, Skin care compositions containing retinoids, Improved method for stability of ageing comprising thirosinase inhibitor activity, Use of ascorbic acid to reduce irritation of topically applied active ingredients, COSMETIC COMPOSITIONS WITH ANTIMICOTIC PROPERTIES, EFFECTIVE AGAINST PSORIASIS AND HAIR LOSS AND COSMETIC METHOD FOR, Treatment or prevention of undesired skin pigmentation, Skin care compositions and method of improving skin appearance, Ultrasound enhancement of percutaneous drug absorption, Skin whiteners containing hydroxytetronic acid, Stabilized retinoid-containing skin care compositions, Retinoid compositions containing a water soluble antioxidant and a chelator, Composition and method for treating rosacea and sensitive skin with free radical scavengers, Skin care compositions containing imidazoles and retinoids, Stable compositions containing a retinoid and an enzyme based antioxidant system, Self-tanning compositions containing dha and propolis extract, Composition and process for stabilizing oxygen-unstable species, Bleaching preparation and cosmetic for preventing and improving aging of skin, Composition and method for the treatment of pigmentation disorders, Composition for cosmetic or pharmaceutical use, Remedies for pigmentation and melanocyte proliferation inhibitors, Public reference made under article 153(3) epc to a published international application that has entered the european phase, Divisional application: reference to earlier application, Information on the status of an ep patent application or granted ep patent. Other solubilities: soluble in alcohol and ether,slightly soluble in benzene,readily soluble in ethanol,acetone and methanol, Needle-like Crystals or Crystalline Powder. 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. Solubility of Hydroquinone. 2y.-;!KZ ^i"L0- @8(r;q7Ly&Qq4j|9 Hydroquinone is combustible when preheated. Hydroquinone is used as a topical application in skin whitening to reduce the color of skin. 322, 4855 (2012), K. Tamura, T. Kasuga, T. Nakagawa, Fluid Phase Equilib. Formula of hydroquinone is . So, does anybody know of another solvent I could use that has a higher . %PDF-1.4 % Monobenzone is the monobenzyl ether of hydroquinone used medically for depigmentation. Conversion factors (at 25C and normal atmospheric pressure) 1 ppm = 4.5 mg/m 3 1 mg/m 3 = 0.222 ppm Table 1. 29(3): 283-330, 1999. Your document download will begin shortly. 2008-2023 ChemPoint. 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. This invention relates to methods and compositions for the treatment of pigmentation disorders, including hyperpigmentation and vitiligo. 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. 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. fungichromin having five-membered rings with one oxygen as the only ring hetero atom, e.g. 38, 565571 (2006), K. Carlsson, B. Karlberg, Anal. Data 53, 12781282 (2008), A. Hydroquinone is combustible when preheated. Eng. Eng. An acceptable carrier also possesses suitable aesthetic and cosmetic qualities and may include emollients, conditioners and the like. protecting the retinoids in a protective system; mixing the hydroquinone, and the protected retinoids; and. Mobility in soil No additional information available 12.5. [34], It is also one of the chemical compounds found in castoreum. 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. 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. 0000005306 00000 n 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. In hydroquinone and sodium metabisulfite compositions, it is believed that the sodium metabisulfite oxidizes first and delays the start of any oxidation of the hydroquinone, so that excessive discoloration is delayed or totally avoided. It does not have the same predisposition to cause dermatitis as metol does. 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. HyTSwoc [5laQIBHADED2mtFOE.c}088GNg9w '0 Jb HYDROQUINONE (hahy droh kwi NOHN) is applied to the the skin to lighten areas that have darkened. 77, No. This chamber is lined with cells that secrete catalases and peroxidases. The document was not able to download due to an unknown error. The Campaign for Safe Cosmetics has also highlighted concerns. Methylaminophenol, used in photography, is produced in this way:[8]. The Boiling Point of hydroquinone is 287C Also, the Melting Point of hydroquinone is 172C. Retinoids are included in the invention from about 0.01 to about 5%, preferably from about 0.025% to about 2.0%, more preferably from about 0.05% to about 1%, and most preferably from about 0.025% to about 0.5%. hydroquinone, 1,4-benzenediol, quinol, 1,4-dihydroxybenzene, p-benzenediol, 4-hydroxyphenol, p-hydroquinone, p-hydroxyphenol, p-dihydroxybenzene, benzoquinol, Electrophoresis, Western Blotting and ELISA, Chromatography and Mass Spectrometry Reagents, Laboratory Syringe Needles and Accessories, Lab Coats, Aprons, and Other Safety Apparel, Sharps Disposal Containers and Accessories, Classroom Laboratory Supplies and Consumables, Applied Biosystems TaqMan Assay and Arrays Search Tool, Applied Biosystems TaqMan Custom Assay Design Tools, Applied Biosystems Custom qPCR Primers and TaqMan Probes Tool, Chemical Storage and Management Resource Center, Solubility in water: 70g/L in water (20C). Production of Hydroquinone Industrial production of hydroquinone usually happens in two ways. The preferred form of protected retinol is manufactured by SunSmart (also known as Particle Sciences, Inc. of Bethlehem, PA) under the brand name of SunCaps A-1283. Pigmentation disorders can take a variety of forms like hyperpigmentation and hypopigmentation, such as melasma (dark patches experienced in pregnancy), liver spots (which often develop with age), as a side effect of birth control pills, and as a persistent result of acne, bums, bites and other skin injuries, and vitiligo. Hydroquinone is sold by chemical suppliers. Learn more about Institutional subscriptions, C. M. S. de Mendona, I. P. de Barros Lima, C. F. S. Arago, A. P. B. Gomes, J. Therm. 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 . Keywords: D-170D; D-170; D170D; D170 Created Date Then add it to the ingredients. Int J Thermophys 42, 1 (2021). Editor's Rating: A specific embodiment of the invention is listed in the following table. Hydroquinone is a white crystalline solid, poorly soluble in water, but more soluble in organic solvents. Other properties of hydroquinone are given in Table 1. 132, 165172 (2018), X. Li, Q. Yin, W. Chen, J. Wang, J. Chem. Eng. All Rights Reserved, View All Eastman Hydroquinone USP Articles. Hydroquinone occurs as fine, white needles. In 1-octanol, the decreasing order of the solubility of these compounds is as follows: resorcinol>benzoic acid>salicylic acid>hydroquinone. [Na+].OC(=O)CN(CC([O-])=O)CCN(CC(O)=O)CC([O-])=O, trimethyl-[phenyl-bis(trimethylsilyloxy)silyl]oxysilane, C[Si](C)(C)O[Si](O[Si](C)(C)C)(O[Si](C)(C)C)C1=CC=CC=C1, C\C(=C/C=O)\C=C\C=C(\C=C\C1=C(CCCC1(C)C)C)/C, 1-hexadecanoyl-2-(9Z,12Z-octadecadienoyl)-sn-glycero-3-phosphocholine, CCCCCCCCCCCCCCCC(=O)OC[C@H](COP([O-])(=O)OCC[N+](C)(C)C)OC(=O)CCCCCCC\C=C/C\C=C/CCCCC, 2-[2-[2-[2-[2-[2-(2-dodecoxyethoxy)ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]ethanol, C[Si]1(C)O[Si](C)(C)O[Si](C)(C)O[Si](C)(C)O[Si](C)(C)O1, O=C1C(=O)C(C2=CNC3=C(C(C(=O)C4=C32)=O)C)=C2C4=CNC2=C1C, [Na+].[Na+].[Na+]. Hydrogen peroxide is used and the reaction gives a mixture of hydroquinone and catechol: An accessible route involves the reaction of sodium hydroxide with 1,4-dichlorobenzene. Heat Mass Transf. If you are already a ChemPoint customer then sign up for access to our online ordering website. The solubilities of benzoic acid, salicylic acid, resorcinol and hydroquinone in water and in 1-octanol were measured by the dynamic method which is also called the synthetic method from 297.25K to 334.45K. Using differential scanning calorimetry (DSC Q2000 and SDT Q600), the melting temperature and the enthalpy of fusion of these solutes were determined. However, hydroquinone discolors at the pH range of 7.0 to 8.5. Hydroquinone IS a white crystalline substance when pure and is highly soluble in water. Glycerol and citric acid, non-toxic and renewable reagents, were crosslinked by a melt polymerization reaction at temperatures from 90-150C. It is a reducmg agent that is reversibly oxidized to semiquinone and quinone. Google Scholar, A.-C. Huang, Y.-K. Chuang, C.-F. Huang, C.-M. Shu, J. Therm. trailer << /Size 393 /Info 347 0 R /Root 375 0 R /Prev 573815 /ID[<6893db2526a970a0c364cca2e99ca522>] >> startxref 0 %%EOF 375 0 obj << /Type /Catalog /Pages 346 0 R /Metadata 348 0 R >> endobj 391 0 obj << /S 2217 /Filter /FlateDecode /Length 392 0 R >> stream 65, 5786 (1998), Y.-H. Zhang, Trends Analyt. Eng. endstream endobj 1 0 obj <> endobj 2 0 obj <> endobj 12 0 obj <>stream . In the United States, the most commonly used treatment for hyperpigmentation is 1,4-benzenediol, which is known as hydroquinone. Provided by the Springer Nature SharedIt content-sharing initiative, Over 10 million scientific documents at your fingertips, Not logged in One embodiment of the invention is a composition which comprises hydroquinone (about 1% to about 12%, preferably about 2% to about 10%, more preferably about 2% to about 8%, more preferably with about 2% to about 4%, and most preferably about 3% to about 4%) and has a neutral pH of from about 5.5 to about 8.0, more preferably a pH of from about 5.5 to about 7.5, and most preferably at a pH of from about 6.0 to about 7.5. Unfortunately, retinoids, in particular retinoic acid, retinal, and their derivatives, isomers and analogs (such as adapalene, tazarotene and isotretoin) also have discoloration problems due to oxidation. Chem. :hS-g"s2Sj Ij=x'V]gPV8tt~qkAVXi|u}5;#.pl-/4JFQ.EP3&F.qa2hI{N qBmG(z#n [GN.}aazN(~8kux9#tnYwIHFuxW v9UNj&ffNW_\\Tc""8=_"7wC>svwQy\^4gF H][QzmlOI(B@ U4[Xb0,|m0*D"/#$\u(QI)RYg\;8 Yjh 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. 0000085850 00000 n M1 and M2 microemulsions contain ethanol as co-surfactant. 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. Exceptional antioxidant qualities are seen at 0.10% (all percentages in the application are weight percent) and above, preferably from about 0.05% to about 0.5% for sodium metabisulfite. I did that by using 1 cup of cream, 4tbsp of hydroquinone and 4tbsp of water or solvent. 4]DYR@'c I'd like the consistency to be thin like a gel so that it absorbs quicker. Antioxidants in the hydroquinone phase are instrumental in stabilizing the color of the hydroquinone composition. Since hydroquinone has a tendency to discolor through oxidation, these antioxidants are used because they have greater tendencies to oxidize than hydroquinone. Anal. Except where otherwise noted, data are given for materials in their, Hydroquinone oxidation with V2O5/NaClO3/H2SO4, http://www.sciencemadness.org/smwiki/index.php?title=Hydroquinone&oldid=11523, Articles containing unverified chemical infoboxes, GNU Free Documentation License 1.3 or later. 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. Recent pieces of . If you have any specific questions, please include them in the comments section. The solubilities in binary and ternary systems of hydroquinone (1,4-dihydroxybenzene) and p-quinone (1,4-benzoquinone) in supercritical carbon dioxide were measured in the pressure range 10.0 to 35.0 MPa at temperatures of 333, 348 and 363 K.In binary systems, the solubility of hydroquinone was three orders of magnitude lower than that of p-quinone. Data 53, 199200 (2008), N. Sunsandee, S. Suren, N. Leepipatpiboon, M. Hronec, U. Pancharoen, Fluid Phase Equilib. Hydroquinone occurs in the environment as a result of anthropogenic processes, as well as in natural products from plants and animals. Protected retinoid may be added to these compositions for additional skin benefit effects. 2023 Springer Nature Switzerland AG. Hydroquinone is a major benzene metabolite, which is a well-known haematotoxic and carcinogenic agent associated with malignancy in occupational environments. Cationic salts of acidic ascorbyl esters, including inorganic salts, preferably magnesium ascorbyl phosphate, and amino acyl derivatives, preferably aminopropyl ascorbyl phosphate, are preferred in this invention. Discoloration of hydroquinone compositions may be accelerated by repeated exposure to oxygen or exposing the compositions to high temperatures, which may be found inside a car or delivery vehicle on a hot sunny day. I've been presented with the problem of trying to dissolve Hydroquinone in a solvent other than water. Data 51, 16681671 (2006), C. L. Yaws, S.-C. Lin, Enthalpy of fusion at freezing pointOrganic compounds, in Thermophysical Properties of Chemicals and Hydrocarbons, William Andrew Publishing (Elsevier, 2009), pp. Cookie Notice Why we like it: This affordable cream contains 2 percent hydroquinone, sunscreen, and costs around five dollars. 0000002198 00000 n Hydroquinone is soluble in alcohol solvents such as ethanol and methanol [17]. Preparation, optimization and in vivo. Color stability improvement is evident at all levels. 2017-02-16T09:38:58+01:00 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. Forms of retinoids have been developed wherein the retinoid is protected by a protective system. Chem. The toxicology of hydroquinone - relevance to occupational and environmental exposure. ;O,1Y+%8#oKT^VWtew4>@V.SR :hmBZ>#ey!UC5! / /n 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.

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