title: Investigation of degradation products in a topical gel containing erythromycin and benzoyl peroxide by liquid chromatography-mass spectrometry.
abstract: Benzamycin, combining benzoyl peroxide and erythromycin, is a topical gel used in the treatment of acne vulgaris. Because of the reactivity of benzoyl peroxide, preparations containing both erythromycin and benzoyl peroxide might be unstable and degradation products could be formed. To investigate and identify these latter products, a gradient-based liquid chromatographic method using volatile mobile phase constituents was developed. Mass spectrometry data were acquired on solutions containing erythromycin and benzoyl peroxide and on freshly prepared, 2-month-old and 18-month-old samples of Benzamycin. With the reference spectra as interpretative templates, it was concluded that erythromycin undergoes oxidation, followed by benzoylation.
authors.affiliation: Laboratorium voor Farmaceutische Chemie en Analyse van Geneesmiddelen, Faculteit Farmaceutische Wetenschappen, Katholieke Universiteit Leuven, O&N 2, Herestraat 49, Postbus 923, B-3000 Leuven, Belgium.
authors.forename: Erik
authors.initials: E
authors.lastname: Haghedooren
authors.forename: Kiran Kumar Raju Bhupathi
authors.initials: KK
authors.lastname: Raju V S
authors.forename: Pieter
authors.initials: P
authors.lastname: Dehouck
authors.forename: Cindy
authors.initials: C
authors.lastname: Govaerts
authors.forename: Ann Van
authors.initials: AV
authors.lastname: Schepdael
authors.forename: Jos
authors.initials: J
authors.lastname: Hoogmartens
authors.forename: Erwin
authors.initials: E
authors.lastname: Adams
mesh_terms: D001585:Benzoyl Peroxide / Q000032:analysis / Q000737:chemistry*; D002626:Chemistry, Pharmaceutical / Q000379:methods*; D002853:Chromatography, Liquid / Q000379:methods*; D004355:Drug Stability; D004917:Erythromycin / Q000032:analysis / Q000737:chemistry*; D005782:Gels / Q000737:chemistry; D013058:Mass Spectrometry / Q000379:methods*; D008956:Models, Chemical; D013678:Technology, Pharmaceutical / Q000379:methods*
chemical_list: D005782:Gels; D004917:Erythromycin; D001585:Benzoyl Peroxide