hydroquinone solubility in glycerin

n3kGz=[==B0FX'+tG,}/Hh8mW2p[AiAN#8$X?AKHI{!7. Some hydroquinone compositions include antioxidants, such as ascorbyl palmitate. 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. 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. Chem. In another embodiment of the invention, hydroquinone and a protected retinoid are both combined in the composition. Hydroquinone | C6H4(OH)2 or C6H6O2 | CID 785 - structure, chemical names, physical and chemical properties, classification, patents, literature, biological activities . 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 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. [17], An important reaction is the conversion of hydroquinone to the mono- and diamine derivatives. J. Chem. ;O,1Y+%8#oKT^VWtew4>@V.SR :hmBZ>#ey!UC5! / /n A common route involves hydroxylation of phenol. Our team has been notified and we will fix it as soon as possible. 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. Inhalation Remove to fresh air. 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. The experimental solubility data was well-correlated with the data, calculated by . Eastman Hydroquinone, USP, meets or exceeds the requirements of the United States Pharmacopoeia and is produced under conditions of current good manufacturing practices (cGMP). Hydroquinone is extensively used as a photographic developer, an antioxidant, and a stabilizing agent for readily oxidizable polymers. 2008-2023 ChemPoint. antiphlogistics and cardiaca, Cosmetics or similar toilet preparations characterised by the composition, Cosmetics or similar toilet preparations characterised by the composition containing inorganic ingredients, Sulfur; Selenium; Tellurium; Compounds thereof, Cosmetics or similar toilet preparations characterised by the composition containing organic compounds, Cosmetics or similar toilet preparations characterised by the composition containing organic compounds containing oxygen, . 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). Stir until uniform. I can't use water because I cannot dissolve enough Hydroquinone into it to reach the desired concentration. 0000002221 00000 n All information collection is solely used to support ChemPoint customers service communications. SAS Anti-ox booster 1% 0.3g. Hydroquinone Revision Date 24-Dec-2021 General Advice If symptoms persist, call a physician. Glycerol and citric acid, non-toxic and renewable reagents, were crosslinked by a melt polymerization reaction at temperatures from 90-150C. The toxicology of hydroquinone - relevance to occupational and environmental exposure. [32], Hydroquinone is thought to be the active toxin in Agaricus hondensis mushrooms. Additionally, the hydroquinone compositions frequently discolor over time and turn from a whitish color to a brown or even black. HyTSwoc [5laQIBHADED2mtFOE.c}088GNg9w '0 Jb 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. Correspondence to Keywords: D-170D; D-170; D170D; D170 Created Date 0000002544 00000 n 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. 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. Hydroquinone is a white, odorless, crystalline solid with an extremely low vapor pressure. Other solubilities: soluble in alcohol and ether,slightly soluble in benzene,readily soluble in ethanol,acetone and methanol, Needle-like Crystals or Crystalline Powder. Part of Springer Nature. 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. 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. Get medical attention. 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. 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 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: 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. &"oq YcbX.=a*t R@ Hydroquinone is an aromatic organic compound which is currently used in two main sectors: . The experimental solubilities were correlated using two regression equations. 43, 13111316 (2007), J. Qing-Zhu, M. Pei-Sheng, Z. Huan, X. Shu-Qian, W. Qiang, Q. Yan, Fluid Phase Equilib. We apologize! 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. Hydroquinone IS a white crystalline substance when pure and is highly soluble in water. - 65.21.225.73. Found. HYPERPIGMENTARY STAIN ELIMINATING CREAM FOR FACE SKIN AND ITS USE. Retinoids are included from about 0.01% to about 5%, preferably from about 0.025% to about 2%, more preferably 0.05% to about 1.0%, and most preferably from about 0.025% to about 0.5%. isosorbide, Ascorbic acid, i.e. We have found that a cream containing 5% of hydroquinone and 0.05 % of laevo-ascorbic acid remains white, and the emulsion remains unbroken after many months of storage, The laevo-ascorbic or cevitamic acid is pr'eferably employed in the free condition; but if desired, the salts, and especially the water-soluble salts thereof, may be employed . I'd like the consistency to be thin like a gel so that it absorbs quicker. 57, 295300 (2013), R. F. Pires, M. R. Franco Jr, Fluid Phase Equilib. Chem. fungichromin, Heterocyclic compounds having oxygen as the only ring hetero atom, e.g. In the environment, hydroquinone showed increased toxicity for aquatic organisms, being less harmful for bacteria and fungi. 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. 132, 165172 (2018), X. Li, Q. Yin, W. Chen, J. Wang, J. Chem. 0000005089 00000 n Preparation, optimization and in vivo. Hydroquinone is a white crystalline solid, poorly soluble in water, but more soluble in organic solvents. 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 . PubMedGoogle Scholar. 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. 2017-02-16T10:10:56+01:00 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. . I would like to add retinol and kojic acid to it as well. ORIGINAL CODE: 0009012, Free format text: Why we like it: This affordable cream contains 2 percent hydroquinone, sunscreen, and costs around five dollars. volume42, Articlenumber:1 (2021) Reddit and its partners use cookies and similar technologies to provide you with a better experience. The document was not able to download due to an unknown error. 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. This medicine may be used for other purposes; ask your health care provider or pharmacist if you have questions. 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. I've been presented with the problem of trying to dissolve Hydroquinone in a solvent other than water. The solubility in water is 6.72g/L. By acting as a free radical scavenger, hydroquinone serves to prolong the shelflife of light-sensitive resins such as preceramic polymers.[18]. It is highly soluble in water (70 g/litre at 25 C) and the log n-octanol/water partition coefficient is 0.59. 0000000731 00000 n 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. For more information, please see our Calorim. Thermodyn. 0 7 r @ &. 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. Conversion factors (at 25 oc and normal atmospheric pressure) 1 ppm = 4.5 mg!m 3 I'm using it for spot treatment of some hyper pigmentation (less than 1% of my body). Diamines, useful in the rubber industry as antiozone agents, are similarly produced from aniline: Hydroquinone has a variety of uses principally associated with its action as a reducing agent that is soluble in water. 12.4. 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. Add the hydroquinone to the water. Since hydroquinone has a tendency to discolor through oxidation, these antioxidants are used because they have greater tendencies to oxidize than hydroquinone. Some products also contain sunscreens. 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. HVoLg~Z+ AzA inhibits tyrosinase. 388, 7381 (2010), H. Li, G. Hu, F. Guo, L. Zhao, J. Zhu, Y. Zhang, Can. It does not have the same predisposition to cause dermatitis as metol does. Canon 0000002585 00000 n 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. 0000002198 00000 n 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. Solute (1 g) Water Boiling Water Alcohol Chloroform Ether Other Acenocoumarol 67,000 280 130 1800 Acetaminophen 20 10 1 N sodium hydroxide, 15 Acetohexamide 230 210 Acetylcysteine 5 4 Acetyldigitoxin 6100 62.5 12 >10,000 Ammonium Alum 7 0.5 Aluminum Chloride 0.9 4 Aluminum Sulfate 1 Amantadine Hydrochloride 2.5 5.1 18 polyethylene glycol 400, 70 [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+]. [22] The FDA stated that hydroquinone cannot be ruled out as a potential carcinogen. Phase A: Dissolve L-Ascorbic Acid in distilled water via agitation and gentle heating (warm, never hot or you will denature the ascorbic acid). Hydroquinone is a white crystalline solid, poorly soluble in water, but more soluble in organic solvents. 0000003430 00000 n At 40C, 4% hydroquinone compositions have the same color stability with slightly more sodium metabisulfite, at least about 0.01% at about 3.5 to about 4.0 pH; at least about 0.05% sodium metabisulfite at about 4.5 to about 6.0 pH; and at pH; at least about 0.05% sodium metabisulfite at about 4.5 to about 6.0 pH; and at least about 0.10% sodium metabisulfite at about 6.5 to about 7.0 pH. By rejecting non-essential cookies, Reddit may still use certain cookies to ensure the proper functionality of our platform. I can only tell you how to mix the powder solution to the liquid solvent. Eng. 58 / Monday, March 26, 2012 / Rules and Regulations 10/31/2017 EN (English US) 6/8 12.3. Editor's Rating: 0.6. glycerin, 2.5. 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. Then take the water and put the measurement into the microwave until boiled. Hydroquinone is soluble in alcohol solvents such as ethanol and methanol [17]. M1 and M2 microemulsions contain ethanol as co-surfactant. Color stability improvement is evident at all levels. Place an order online, track your orders, download SDS and TDS, and see your quotes, all in one secure place. wG xR^[ochg`>b$*~ :Eb~,m,-,Y*6X[F=3Y~d tizf6~`{v.Ng#{}}jc1X6fm;'_9 r:8q:O:8uJqnv=MmR 4 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 composition is color stabilized and cosmetically elegant. Anal. x- [ 0}y)7ta>jT7@t`q2&6ZL?_yxg)zLU*uSkSeO4?c. R -25 S>Vd`rn~Y&+`;A4 A9 =-tl`;~p Gp| [`L` "AYA+Cb(R, *T2B- Lastly, I'd like to add benzoic acid for preservation purposes. However, a problem with a formulation containing both retinoids and hydroquinone has been their incompatible pH ranges. [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. A preferred embodiment utilizes encapsulation. The amount of crosslinking was controlled by the reaction conditions, including temperature, reaction time, and . Solubility of Hydroquinone. 0000000807 00000 n 4. 250, 165172 (2006), F. L. Mota, A. J. Queimada, A. E. Andreatta, S. P. Pinho, E. A. Macedo, Fluid Phase Equilib. 114, 175188 (1996), I. Hahnenkamp, G. Graubner, J. Gmehling, Int. 38, 565571 (2006), K. Carlsson, B. Karlberg, Anal. With respect to organic solvents, the solubility varies from 57% in ethanol to less than 0.1% in benzene. The solubility was increased by addition of ethanol, reached a maximum . Eng. HMkA+"c>jZ^ho=81NW;]Ib;+i#iFArHpz). `9F6~qg3]0,#!V9Q> p=|h| It is a reducmg agent that is reversibly oxidized to semiquinone and quinone. 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 Some documentation and label information may refer to the legacy brand. Bioaccumulative potential Hydroquinone (123 -31 -9) Bioaccumulative potential Not established. Eye Contact Rinse immediately with plenty of water, also under the eyelids, for at least 15 minutes. https://doi.org/10.1007/s10765-020-02750-4. Chim. 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. Hope it helps 6 yrs later. 230, 176183 (2005), A. Apelblat, E. Manzurola, N. A. Balal, J. Chem. Hydroquinone is a major benzene metabolite, which is a well-known haematotoxic and carcinogenic agent associated with malignancy in occupational environments. 49, 313321 (2015). An acceptable carrier also possesses suitable aesthetic and cosmetic qualities and may include emollients, conditioners and the like. 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 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. 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. V)gB0iW8#8w8_QQj@&A)/g>'K t;\ $FZUn(4T%)0C&Zi8bxEB;PAom?W= Data 51, 127129 (2006), J. Lim, S. Jang, H. K. Cho, M. S. Shin, H. Kim, J. Chem. 77, No. 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. 2y.-;!KZ ^i"L0- @8(r;q7Ly&Qq4j|9 Classical photo shops . : Metabolism and disposition of hydroquinone in Fischer 344 rats after oral or dermal administration. Place water in container then bring the temperature to 15c in a boil bath then add products at this point when youre making the lotion u will need to add the other ingredients. 0000003660 00000 n 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.