By acting as a free radical scavenger, hydroquinone serves to prolong the shelflife of light-sensitive resins such as preceramic polymers.[18]. Consistent with a condensation reaction, water was determined to be the primary byproduct. Forms of retinoids have been developed wherein the retinoid is protected by a protective system. [27] Several such agents are already available or under research,[28] including azelaic acid,[29] kojic acid, retinoids, cysteamine,[30] topical steroids, glycolic acid, and other substances. The experimental solubility data was well-correlated with the data, calculated by . PubMedGoogle Scholar. vz >I d50dwp?i4,H3. Part of Springer Nature. Fill out the form below, and we will send you the document as soon as we can! These phases (described below) are combined in a mixing tank with an in-line homogenizer as follows. It is a reducing agent that is reversibly oxidized to semiquinone and quinone. Chemically, hydroquinone is designated as p-dihydroxybenzene; the empirical formula is C 6 H 6 O 2; molecular weight is 110.0. Hydroquinone Safety Data Sheet according to Federal Register / Vol. wG xR^[ochg`>b$*~ :Eb~,m,-,Y*6X[F=3Y~d tizf6~`{v.Ng#{}}jc1X6fm;'_9 r:8q:O:8uJqnv=MmR 4 We have discovered that a hydroquinone composition (with about 1 to about 12% hydroquinone, preferably with about 2% to about 10%, more preferably with about 2% to about 8%, more preferably with about 2% to about 4%, most preferably with about 3% to about 4% hydroquinone) with preferably a 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, can include cationic salts of acidic ascorbyl esters, preferably sodium ascorbyl phosphate, more preferably aminopropyl ascorbyl phosphate, most preferably magnesium ascorbyl phosphate as an antioxidant and the color destabilization problems are appreciably less as compared to hydroquinone compositions without such a cationic salt of acidic ascorbyl esters in the neutral pH range: preferably a 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. Found. It is also used to prepare 2% bleaching creams and certain intermediates for the synthesis of dyes, and it has some activity as an antitumoragent. You can expect to hear back from a ChemPoint product specialist within 1 business hour. This Thermo Scientific Chemicals brand product was originally part of the Acros Organics product portfolio. However, a problem with a formulation containing both retinoids and hydroquinone has been their incompatible pH ranges. Reference Tables: SOLUBILITIES - uspbpep.com Calorim. 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. 322, 4855 (2012), K. Tamura, T. Kasuga, T. Nakagawa, Fluid Phase Equilib. 15, 188196 (1996), U. Domaska, Fluid Phase Equilib. Then take the water and put the measurement into the microwave until boiled. 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. Do not put this product in the microwave. PDF Solubilityof Eastman hydroquinone andderivatives 108. Additionally, a water-soluble antioxidant, preferably a sulfite, including but not limited to sulfites, bisulfites, metabisulfites, their salts and their derivatives, most preferably sodium metabisulfite, may be helpful in stabilizing the hydroquinone composition. 4. Stabilisation of biofuels with hydrophilic, natural antioxidants It is soluble in water. Solubility: Moderately soluble in water, glycerin, propylene glycol, and highly soluble in ethanol Features & Benefits Can work in conjunction with glycolic acid to help reduce pigment in melasma Non-GMO Extremely low vapor pressure USP Grade European Pharma Grade Drug master file available upon request Applications Inhalation Remove to fresh air. How to dissolve Hydroquinone to make 4 oz. - ACS Community Sodium metabisulfite has the added advantage that it does not discolor by oxidation. Preparation, optimization and in vivo. 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 [ A3, Free format text: PDF HYDROQUINONE - Centers for Disease Control and Prevention 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. One skilled in the art is familiar with the known protective system technologies, such as encapsulation and entrapment methodologies. Thanks to the added vitamin E, it leaves your skin feeling smooth and soft, too. Antioxidants, preferably sulfites, including but not limited to sulfites, bisulfites, metabisulfites, their salts, and their derivatives, most preferably sodium metabisulfite, have been used to stabilize certain compositions, which have included hydroquinone. Protected retinoid may be added to these compositions for additional skin benefit effects. Variations in pH have proven to result in excessive discoloration ranging from brownish to black. Solubility of Hydroquinone in Different Solvents from 276.65 K to 345. A common route involves hydroxylation of phenol. 0000002379 00000 n 88, 161164 (2010), J. Delgado, Int. and our Hydroquinone is sold by chemical suppliers. Methylaminophenol, used in photography, is produced in this way:[8]. Hydroquinone occurs in the environment as a result of anthropogenic processes, as well as in natural products from plants and animals. Phase B: Dissolve the ferulic acid in the glycerin - some "spirited" stirring may be necessary. RJPT - Hydroquinone Solubility in Pure and Binary Solvent Mixture at Have an order or account question? Why we like it: This affordable cream contains 2 percent hydroquinone, sunscreen, and costs around five dollars. By clicking Accept, you consent to the use of cookies. This chamber is lined with cells that secrete catalases and peroxidases. Additionally, the hydroquinone compositions frequently discolor over time and turn from a whitish color to a brown or even black. 0000004197 00000 n This study was funded by Ministre de l'Enseignement Suprieur et de la Recherche Scientifique. 0000004433 00000 n Ferulic acid 0.5% 0.15g. 552591, Z. Esina, M. Korchuganova, Theor. Protected retinoid, with its skin benefit capabilities, may also be included with the hydroquinone composition. :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 Hydroquinone is a white crystalline solid, poorly soluble in water, but more soluble in organic solvents. For a shipping quote, check the box and the bottom and provide us your shipping information. volume42, Articlenumber:1 (2021) 115, 22772285 (2014), Article J. Chem. : Metabolism and disposition of hydroquinone in Fischer 344 rats after oral or dermal administration. Hydroquinone - an overview | ScienceDirect Topics [O-]C(=O)C1=NN(C=2C=CC(=CC=2)S([O-])(=O)=O)C(O)=C1\N=N\C1=CC=C(S([O-])(=O)=O)C=C1, OC1=C(C)C(C)=C2O[C@@](CCC[C@H](C)CCC[C@H](C)CCCC(C)C)(C)CCC2=C1C, Antibiotics FOR TREATMENT OF HEMORRHOIDS AND ANAL FISSURES FOR TOPICAL USE, CCCCCCCCCCCCCCCC(=O)OC[C@H](O)[C@H]1OC(=O)C(O)=C1O, [(2R)-2-[(1S)-1,2-dihydroxyethyl]-3-hydroxy-5-oxo-2H-furan-4-yl] dihydrogen phosphate, [Na+]. Such carriers are widely known in the art and deliver the composition's ingredients to the skin without excessive degradation, inactivation or other unwanted interaction. A further embodiment of the invention includes a method for stabilizing a hydroquinone composition (with about 1% to about 12% hydroquinone, preferably about 2% to about 10%, more preferably about 2% to about 8%, and most preferably about 3% to about 4%) with 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, by adding 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, preferably sodium ascorbyl phosphate, more preferably aminopropyl ascorbyl phosphate, most preferably magnesium ascorbyl phosphate. Hydroquinone can lose a hydrogen cation from both hydroxyl groups to form a diphenolate ion. 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. 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. Hydroquinone is a white, odorless, crystalline solid with an extremely low vapor pressure. Hydroquinone is a white crystalline solid, poorly soluble in water, but more soluble in organic solvents. Hydroquinone (C6H4(OH)2), also known as benzene-1,4-diol or quinol, is an aromatic organic compound, with a variety of uses in chemistry. 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. However, the oil-soluble TBHQ is more hydrophobic with a distinctly increased log P value compared to HQ. The present invention combats this problem, with hydroquinone compositions in the neutral pH range, preferably a 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. Int J Thermophys 42, 1 (2021). For more information, please see our 2y.-;!KZ ^i"L0- @8(r;q7Ly&Qq4j|9 On this Wikipedia the language links are at the top of the page across from the article title. ORIGINAL CODE: 0009012, Free format text: [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. 0000008435 00000 n 0000003660 00000 n This composition is color stabilized and cosmetically elegant. The solubility was increased by addition of ethanol, reached a maximum . 250, 165172 (2006), F. L. Mota, A. J. Queimada, A. E. Andreatta, S. P. Pinho, E. A. Macedo, Fluid Phase Equilib. I can't use water because I cannot dissolve enough Hydroquinone into it to reach the desired concentration. 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. Some documentation and label information may refer to the legacy brand. The solubility in water is 6.72g/L. Provided by the Springer Nature SharedIt content-sharing initiative, Over 10 million scientific documents at your fingertips, Not logged in Conversion factors (at 25C and normal atmospheric pressure) 1 ppm = 4.5 mg/m 3 1 mg/m 3 = 0.222 ppm Table 1. 2017-02-16T10:10:56+01:00 Other solubilities: soluble in alcohol and ether,slightly soluble in benzene,readily soluble in ethanol,acetone and methanol, Needle-like Crystals or Crystalline Powder. Hydroquinone compositions are effective but have some undesirable side effects. HYdroquinone can be found in various skin care products. Chim. application/pdf Phillip M. Hudnall "Hydroquinone" in Ullmann's Encyclopedia of Industrial Chemistry 2002, Wiley-VCH, Weinheim. The Beaver: Its Life and Impact. The aquatic toxicity of hydroquinone to fresh water fish, Daphnia, and algae was between 0.050- . https://doi.org/10.1007/s10765-020-02750-4. Thermodyn. Acta 423, 137144 (2000), S.-T. Lin, S. I. Sandler, Ind. V)gB0iW8#8w8_QQj@&A)/g>'K t;\ $FZUn(4T%)0C&Zi8bxEB;PAom?W= 0000005306 00000 n 2023 Springer Nature Switzerland AG. 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. [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+]. Crit. The process of making a stable hydroquinone composition having a pH of about 5.5 to about 8.0 comprising: combining the following ingredients, in a carbon dioxide atmosphere: first, magnesium ascorbyl phosphate and sodium metabisulfite, then, third, magnesium ascorbyl phosphate, then, Application filed by Medicis Pharmaceutical Corp, [H]O[C@@]([H])(C([H])([H])O*)[C@@]1([H])OC(=O)C(O*)=C1O*, OC\C=C(/C)\C=C\C=C(/C)\C=C\C1=C(C)CCCC1(C)C, 3-aminopropyl [(2R)-2-[(1S)-1,2-dihydroxyethyl]-3-hydroxy-5-oxo-2H-furan-4-yl] hydrogen phosphate, NCCCOP(O)(=O)OC1=C(O)[C@@H]([C@@H](O)CO)OC1=O, OC(=O)C=C(C)/C=C/C=C(C)C=CC1=C(C)CCCC1(C)C, OC(=O)/C=C(\C)/C=C/C=C(C)C=CC1=C(C)CCCC1(C)C, trisodium;[(5R)-5-[(1S)-1,2-dihydroxyethyl]-2-oxido-4-oxofuran-3-yl] phosphate, [Na+].[Na+]. Hydroquinone is combustible when preheated. ;O,1Y+%8#oKT^VWtew4>@V.SR :hmBZ>#ey!UC5! / /n It has a white-solid appearance. In the environment, hydroquinone showed increased toxicity for aquatic organisms, being less harmful for bacteria and fungi. Hydroquinone: Environmental Pollution, Toxicity, and Microbial Answers D7VJV//KZ&t}JSW/L@,l@^ D@ @8 i W `^;V rD}25p>.Bv1}\_E p9 endstream endobj 392 0 obj 1303 endobj 376 0 obj << /Type /Page /Parent 350 0 R /Resources 377 0 R /Contents 381 0 R /MediaBox [ 0 0 595 842 ] /CropBox [ 0 0 595 842 ] /Rotate 0 >> endobj 377 0 obj << /ProcSet [ /PDF /Text ] /Font << /TT2 379 0 R /TT4 383 0 R /TT6 385 0 R >> /ExtGState << /GS1 387 0 R >> /ColorSpace << /Cs6 378 0 R >> >> endobj 378 0 obj [ /ICCBased 386 0 R ] endobj 379 0 obj << /Type /Font /Subtype /TrueType /FirstChar 32 /LastChar 252 /Widths [ 250 0 408 500 0 833 778 180 333 333 500 564 250 333 250 278 500 500 500 500 500 500 500 500 500 500 278 278 564 564 564 444 921 722 667 667 722 611 556 722 722 333 389 722 611 889 722 722 556 722 667 556 611 722 722 944 722 722 611 333 0 333 0 500 0 444 500 444 500 444 333 500 500 278 278 500 278 778 500 500 500 500 333 389 278 500 500 722 500 500 444 0 0 0 541 0 0 0 0 0 0 0 500 0 0 0 0 0 0 0 0 0 0 0 333 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 0 400 0 0 0 0 576 0 0 0 0 0 0 0 750 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 722 0 0 0 0 0 722 0 0 500 444 0 0 0 444 0 0 0 444 444 0 0 0 0 0 0 0 0 0 0 500 0 500 0 0 0 0 0 500 ] /Encoding /WinAnsiEncoding /BaseFont /BCGIOE+TimesNewRoman /FontDescriptor 380 0 R >> endobj 380 0 obj << /Type /FontDescriptor /Ascent 891 /CapHeight 656 /Descent -216 /Flags 34 /FontBBox [ -568 -307 2028 1007 ] /FontName /BCGIOE+TimesNewRoman /ItalicAngle 0 /StemV 94 /XHeight 0 /FontFile2 388 0 R >> endobj 381 0 obj << /Length 462 /Filter /FlateDecode >> stream Azelaic acid - Wikipedia HYDROQUINONE (DIHYDROXYBENZENE) | Occupational Safety and Health Other aspects, advantages, and modifications are evident from a review of the following claims. [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+]. uuid:3780f5dc-b322-4e29-9b1d-4c4d10b1e282 Some hydroquinone compositions include antioxidants, such as ascorbyl palmitate. Hydrquinone Cas N: 123-31-9 - Oecd Some may double boil the hydroquinone and ester, I was too scared of the possibility of combustion. S.C. Gad, T. Pham, in Encyclopedia of Toxicology (Third Edition), 2014 Environmental Fate and Behavior. N')].uJr ORIGINAL CODE: 0009013, Ref document number: Eng. Hydroquinone USP, Eastman - ChemPoint sulfur acids, imidic, hydrazonic, hydroximic acids, Carboxylic acids, e.g. Have an order or account question, find answers in our Online Support articles. ~lgM~Gc{1S_1Q/_/v">S 9 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). Cat No. : H329-500 HMkA+"c>jZ^ho=81NW;]Ib;+i#iFArHpz). `9F6~qg3]0,#!V9Q> p=|h| Hydroquinone is considered to be readily biodegrable and photodegradable. All Rights Reserved, View All Eastman Hydroquinone USP Articles. Eastman Hydroquinone, USP, meets or exceeds the requirements of the United States Pharmacopoeia and is produced under conditions of current good manufacturing practices (cGMP). 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. 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. Remove contact lenses, if present and easy to do. Substituted derivatives of this parent compound are also referred to as hydroquinones. endstream endobj 276 0 obj <>stream [21][25][23] NTP evaluation showed some evidence of long-term carcinogenic and genotoxic effects[26], While hydroquinone remains widely prescribed for treatment of hyperpigmentation, questions raised about its safety profile by regulatory agencies in the EU, Japan, and USA encourage the search for other agents with comparable efficacy. The experimental solubilities were correlated using two regression equations. Data 51, 127129 (2006), J. Lim, S. Jang, H. K. Cho, M. S. Shin, H. Kim, J. Chem. I can't use water because I cannot dissolve enough Hydroquinone into it to reach the desired concentration. [31], Hydroquinones are one of the two primary reagents in the defensive glands of bombardier beetles, along with hydrogen peroxide (and perhaps other compounds, depending on the species), which collect in a reservoir. I've been presented with the problem of trying to dissolve Hydroquinone in a solvent other than water. 374 0 obj << /Linearized 1 /O 376 /H [ 807 1414 ] /L 581425 /E 96582 /N 109 /T 573826 >> endobj xref 374 19 0000000016 00000 n International Journal of Thermophysics So, does anybody know of another solvent I could use that has a higher solubility and is relatively non-toxic. 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. 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 The Boiling Point of hydroquinone is 287C Also, the Melting Point of hydroquinone is 172C. Appearance: Free-flowing white crystalsOdor: OdorlessMolecular weight: 110.11Empirical formula: C6H6O2Assay (Anhydrous basis): 99.0-100.5 %Melting point: 172-174CWater: 0.5 wt % max.Residue on ignition: 0.5 % maxSolubility: Moderately soluble in water, glycerin, propylene glycol, and highly soluble in ethanol, Can work in conjunction with glycolic acid to help reduce pigment in melasma Non-GMOExtremely low vapor pressureUSP GradeEuropean Pharma GradeDrug master file available upon request. The reservoir opens through a muscle-controlled valve onto a thick-walled reaction chamber. How do I dissolve hydroquinone powder to make a 20% and 10% concentration? Hydroquinone is 1,4-benzenediol. Hydroquinone | C6H4(OH)2 or C6H6O2 | CID 785 - structure, chemical names, physical and chemical properties, classification, patents, literature, biological activities . [34], It is also one of the chemical compounds found in castoreum. 38, 565571 (2006), K. Carlsson, B. Karlberg, Anal. 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 solubility in water is 6.72g/L. 4]DYR@'c Solubility of Hydroquinone : r/OrganicChemistry Hydroquinone, like phenols are very weak acids and can be deprotonated. Phase A is added to the tank, which is held at a temperature of from about 70 to about 75 C, and in which a CO. https://doi.org/10.1007/s10765-020-02750-4, DOI: https://doi.org/10.1007/s10765-020-02750-4. 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. The present invention is not to be limited by any mechanism described in the specification, because it is defined by the claims. 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.