Dose formulation and analysis of diapocynin.
Procedures based on high-performance liquid chromatography (HPLC) with ultraviolet (UV) detection and liquid chromatography-mass spectrometry (LC-MS) are described for analyzing diapocynin. Diapocynin was synthesized by oxidative coupling of two apocynin monomers, through the in situ generation of sulfate radicals. It was purified by washing 3 times each with boiling water, followed by boiling methanol. HPLC was used to determine the concentration of unreacted apocynin and other impurities and the purity of the diapocynin that had been synthesized. Negative-ion, atmospheric pressure chemical ionization (APCI) LC-MS was used to determine the molecular weights of impurities. The method using HPLC with UV detection provided a calibration curve that was linear from 0.16 to 24 microg/mL. The LC-MS method was linear from 0.005 to 2 microg/mL. It was found that diapocynin has low solubility in deionized water and corn oil but is soluble in dimethylsulfoxide (DMSO) and alkaline aqueous solutions. Also, diapocynin is 13 times more lipophilic than apocynin, even though both compounds have the same p K a of 7.4. The log of the octanol/water partition coefficient (log P) was 1.01 for apocynin and 1.82 for diapocynin. A solution of 5.5 mg/mL (16.7 mM) diapocynin in DMSO was found to be stable for at least 30 days when stored at room temperature.
Luchtefeld
Ron
R
Total Diet and Pesticide Research Center, United States Food and Drug Administration, 11510 West 80th Street, Lenexa, Kansas 66214, USA.
Luo
Rensheng
R
Stine
Keith
K
Alt
Mikaela L
ML
Chernovitz
Patricia A
PA
Smith
Robert E
RE
D000098:Acetophenones / Q000032:analysis* / Q000138:chemical synthesis* / Q000737:chemistry*; D000975:Antioxidants / Q000737:chemistry*; D001713:Biphenyl Compounds / Q000032:analysis* / Q000138:chemical synthesis* / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D003314:Corn Oil; D004121:Dimethyl Sulfoxide; D004355:Drug Stability; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry / Q000379:methods; D010084:Oxidation-Reduction; D012995:Solubility; D012996:Solutions; D013431:Sulfates / Q000737:chemistry; D014867:Water
D000098:Acetophenones; D000975:Antioxidants; D001713:Biphenyl Compounds; D012996:Solutions; D013431:Sulfates; C527766:diapocynin; C069025:sulfate radical; D014867:Water; D003314:Corn Oil; C056165:acetovanillone; D004121:Dimethyl Sulfoxide