Photodegradation study of a new activator of the cystic fibrosis chloride channel, the 6-hydroxy-10-chlorobenzo[c]quinolizinium chloride (MPB-07)
✍ Scribed by Jean-Christophe Olivier; Joachim Manceau; Cécile Marivingt-Mounir; Yvette Mettey; Jean-Michel Vierfond; William Couet
- Book ID
- 102400770
- Publisher
- John Wiley and Sons
- Year
- 2002
- Tongue
- English
- Weight
- 151 KB
- Volume
- 91
- Category
- Article
- ISSN
- 0022-3549
No coin nor oath required. For personal study only.
✦ Synopsis
The photodegradation of 6-hydroxy-10-chlorobenzo[c]quinolizinium chloride (MPB-07), a new activator of the transmembrane conductance regulator chloride channel, was studied in aqueous solutions exposed to arti®cial daylight (2300 Lux intensity). Various conditions of pH, concentration, and temperature were used. MPB-07 concentration was determined at regular time intervals by reversed-phase HPLC. MPB-07 stability was also studied at pH 7.4 in the dark. Results showed that in all the conditions tested MPB-07 underwent rapid photodegradation, apparently following ®rst-order kinetics. Rate constants were dependent on the initial MPB-07 concentration, temperature, and pH. At pH 7.4, and for concentrations from 1 to 125 mM, half-lives ranged from 0.681 AE 0.047 to 4.54 AE 0.28 h. The Arrhenius plot was linear and activation energy was calculated to be 20.7 kJ Á mol À1 . Analysis by chemical ionization-mass spectrometry showed that the chlorine atom of the MPB-07 molecule might be replaced by an OH group during the photodegradation process. In the dark, MPB-07 in solutions at pH 7.4 was found to be stable over a 6-week period. In conclusion, MPB-07 is a highly photolabile molecule that should be carefully protected from light when used. ß 2002