Free Access
Volume 28, Number 6, July/August 2000
Nitric oxide and superoxide in biological systems
Page(s) 557 - 560
Section Original articles
Analusis 28, 557-560 (2000)
DOI: 10.1051/analusis:2000171

Influence of pH on the photodegradation kinetics under UV light of climbazole solutions

C. Couteau, M. Jadaud, F. Peigne and L.J.M. Coiffard

Laboratory of Industrial Pharmacy, School of Pharmacy, University of Nantes, rue du Moulin de la Rousselière, CP 4301, 44805 Saint-Herblain Cedex, France

(Received May 29, 2000; revised August 16, 2000; accepted August 29, 2000.)

The objective of this research was to study the effect of pH on the photodegradation kinetics of 15.8 $\mu$ aqueous solutions of climbazole. A high-performance liquid chromatographic method for the quantification of climbazole after irradiation of aqueous solutions was carried out, using a RP-18 column with a acetonitrile - 0.05 M sodium perchlorate mobile phase. The detector was set at a wavelength of 220 nm. Calibration curve showed linear response in the interval 5 to 25 $\mu$ Photodegradation appeared to follow first-order kinetics and was found pH-dependent. The degradation rate constant was calculated to be 10.5 $\times$ 10-3, 9.9 $\times$ 10-3 and 16.5 $\times$ 10-3 min-1, respectively at pH 5, 7 and 9.

Key words: Climbazole -- photodegradation kinetics -- HPLC.

© EDP Sciences, Wiley-VCH 2000