title: Stability of 4-DMAP in solution.
abstract: A stability-indicating reversed-phase performance liquid chromatographic method was developed for the detection of 4-(N,N-dimethylamino)phenol (4-DMAP) and its degradation products under accelerated degradation conditions. The degradation kinetics of 4-DMAP in aqueous solution over a pH range of 1.12-6.05 and its stability in solutions based on propylene glycol or polyethylene glycol 400 were investigated. The observed rate constants were shown to follow, apparent first-order kinetics in all cases. The pH rate profile shows that maximum stability of 4-DMAP was observed in the pH range 2.0 to 3.0. Acid/base catalysis of 4-DMAP was not affected by systems of various ionic strengths. Incorporation of nonaqueous propylene glycol or polyethylene glycol 400 in the pH 3.05 solution of 4-DMAP showed an increase in the stability at 55 degrees C +/- 0.5 degrees C.
authors.affiliation: School of Pharmacy, National Defense Medical Center, Neihu, Taiwan, Republic of China.
authors.forename: D P
authors.initials: DP
authors.lastname: Wang
authors.forename: L C
authors.initials: LC
authors.lastname: Chang
authors.forename: M T
authors.initials: MT
authors.lastname: Wang
mesh_terms: D015761:4-Aminopyridine / Q000031:analogs & derivatives* / Q000737:chemistry*; D000931:Antidotes / Q000737:chemistry*; D002021:Buffers; D002851:Chromatography, High Pressure Liquid; D004355:Drug Stability; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D012997:Solvents; D013696:Temperature
chemical_list: D000931:Antidotes; D002021:Buffers; D012997:Solvents; D015761:4-Aminopyridine; C003885:4-dimethylaminopyridine