Name: Adipic Acid
CAS No: Hexanedioicacid [124-04-9]
PhEur:AdipicAcid USP-NF:AdipicAcid
Acidumadipicum; acifloctin; acinetten; adilactetten; asapic; 1,4 butanedicarboxylicacid;E355;1,6-hexanedioicacid;InipolDS.
Hexanedioicacid [124-04-9]
C6H10O4 146.14
Adipic acid is used as an acidifying and buffering agent in intramuscular, intravenous and vaginal formulations. It is also usedinfoodproductsasaleavening,pH-controlling,orflavoring agent. Adipic acid has been incorporated into controlled-release formulationmatrix tablets toobtainpH-independent release for bothweaklybasic(1,2)andweaklyacidicdrugs.(3,4) Ithasalsobeen incorporatedintothepolymericcoatingofhydrophilicmonolithic systemstomodulatetheintragelpH,resultinginzero-orderrelease ofahydrophilicdrug.(5)Thedisintegrationat intestinalpHof the entericpolymershellachasbeenreportedtoimprovewhenadipic acidwasusedasapore-formingagentwithoutaffectingreleasein the acidicmedia.(6) Other controlled-release formulations have includedadipicacidwith the intentionof obtaininga late-burst releaseprofile.(7)
Adipicacidoccursasawhiteoralmostwhite,odorlessnonhygro scopic crystallinepowder.The crystal structureof adipicacid is monoclinicholohedral.
See Table I.
Acidity/alkalinity pH=2.7(saturatedsolutionat258C);pH=3.2 (0.1%w/vaqueoussolutionat258C) Boilingpoint 337.58C Dissociationconstant pKa1:4.418at258C; pKa2:5.412at258C. Density 1.360g/cm3 Flashpoint 1968C(closedcup) Heat of combustion 17653.9kJ/mol (4219.28kcal/mol) at 258C Heat of solution 33.193kJ/mol (7.9kcal/mol) at 258C Melting point 152.18C Solubility see Table II. Vapor pressure 133.3Pa (1mmHg) at 159.58C Viscosity (dynamic) 4.54mPas (4.54cP) at 1608C for molten adipic acid
Adipic acid is normally stable but decomposes above boiling point. It should be stored in a tightly closed container in a cool, dry place, and should be kept away from heat, sparks, and open flame.
Adipic acid is incompatible with strong oxidizing agents as well as strong bases and reducing agents. Contact with alcohols, glycols, aldehydes, epoxides, or other polymerizing compounds can result in violent reactions
Adipic acid is prepared by nitric acid oxidation of cyclohexanol or cyclohexanone or a mixture of the two compounds. Recently, oxidation of cyclohexene with 30% aqueous hydrogen peroxide under organic solvent- and halide-free conditions has been proposed as an environmentally friendly alternative for obtaining colorless crystalline adipic acid.(8
Adipic acid is used in pharmaceutical formulations and food products. The pure form of adipic acid is toxic by the IP route, and moderately toxic by other routes. It is a severe eye irritant, and may cause occupational asthma. LD50 (mouse, IP): 0.28g/kg(9) LD50 (mouse, IV): 0.68g/kg LD50 (mouse, oral): 1.9g/kg LD50 (rat, IP): 0.28g/kg LD50 (rat, oral): >11g/kg
Observe normal precautions appropriate to the circumstances and quantity of the material handled. Adipic acid is combustible and can react with oxidizing materials when exposed to heat and flame. It emits acrid smoke and fumes when heated to decomposition. Dust explosion is possible if in powder or granular form, mixed with air. Adipic acid irritates the eyes and respiratory tract. Protective equipment such as respirators, safety goggles, and heavy rubber gloves should be worn when handling adipic acid
GRAS listed. Included in the FDA Inactive Ingredients Database (IM, IV, and vaginal preparations). Accepted for use as a food additive in Europe. Included in an oral pastille formulation available in the UK. Included in the Canadian List of Acceptable Non-medicinal Ingredients.
Not Found
A specification for adipic acid is contained in the Food Chemicals Codex (FCC).(10) The EINECS number for adipic acid is 204-673-3. The PubChem Compound ID (CID) for adipic acid is 196.