title: LC separation of calcipotriol from its photodegradation products and protection possibilities using adjuvants.
abstract: Mobile phase optimization and reversed-phase column characteristics were used to separate photodegradation products from the parent compound, 24-cyclopropyl-9-,10-secochola-5,7,10(19),22-tetraene-1alpha,3beta,24-triol (calcipotriol). Separation between calcipotriol and its degradation products was obtained with an acetonitrile/water (53:47, v/v) mobile phase on a C(18) Hypersil ODS column (250 mm length, 4.6 mm id, 5 microm particle size) and a flow rate of 1 ml/min. Using this system, the influence of commonly used solvents in dermatology on degradation was studied. The addition of a UV filter in two concentrations was also evaluated for its possible protective effect to light exposure. Propylene glycol and polyethylene glycol 400 decreased the speed of degradation. The sunscreen 2-hydroxy-4-methoxybenzophenone affords a protection proportional to the filter concentration used in the study.
authors.affiliation: Department of Pharmaceutical Technology and Physical Pharmacy, Pharmaceutical Institute, Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090 Brussels, Belgium.
authors.forename: J J
authors.initials: JJ
authors.lastname: Cirunay
authors.forename: Y
authors.initials: Y
authors.lastname: Vander Heyden
authors.forename: J
authors.initials: J
authors.lastname: Plaizier-Vercammen
mesh_terms: D002117:Calcitriol / Q000031:analogs & derivatives / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D003879:Dermatologic Agents / Q000032:analysis*; D004355:Drug Stability; D008027:Light
chemical_list: D003879:Dermatologic Agents; C055085:calcipotriene; D002117:Calcitriol