title: The effect of beta-carotene on the photostability of nisoldipine.
abstract: The effect of beta-carotene on the photostability of nisoldipine (NS) has been investigated. Light stability studies were carried out following the recommendations of the International Conference on Harmonization (ICH), version I, using a high-pressure mercury lamp, type HBO-50, equipped with the interference filter and Wood's filter to isolate 365 nm wavelength. The photodegradation process was assayed by means of UV spectrophotometry and the reversed phase High-Performance Liquid Chromatography (HPLC). The quantum yields of photodegradation of NS and NS in the presence of beta-carotene were determined using the Reinecke salt as a chemical actinometer. The methanol solutions of NS degraded following apparent first-order kinetics. The degradation rate constant decreased as beta-carotene concentration increased. To verify the photostabilising role of the dye, a Stern-Volmer plot was constructed. The results have proved that beta-carotene does not act as a photosensitiser.
authors.affiliation: Department of Inorganic and Analytical Chemistry, University of Medical Sciences, Poznan, Poland. jmielcar@am.poznan.pl
authors.forename: J
authors.initials: J
authors.lastname: Mielcarek
authors.forename: P
authors.initials: P
authors.lastname: Grobelny
authors.forename: O
authors.initials: O
authors.lastname: Szamburska
mesh_terms: D002121:Calcium Channel Blockers / Q000737:chemistry* / Q000528:radiation effects; D004355:Drug Stability; D007700:Kinetics; D008956:Models, Chemical; D015737:Nisoldipine / Q000737:chemistry* / Q000528:radiation effects; D011310:Preservatives, Pharmaceutical / Q000737:chemistry*; D014466:Ultraviolet Rays; D019207:beta Carotene / Q000737:chemistry*
chemical_list: D002121:Calcium Channel Blockers; D011310:Preservatives, Pharmaceutical; D019207:beta Carotene; D015737:Nisoldipine