Studies on photolysis kinetics of combretastatin A4 phosphate solution

Abstract

OBJECTIVE: To study photolysis kinetics of combretastatin A4 phosphate solution. METHODS: CA4P solution was exposed to different light. Samples were determined by HPLC. RESULTS: The photolysis kinetics of CA4P solution at different concentration under the same light was different. The photolysis kinetics of CA4P solution at the same concentration under different light was different. Under mercury lamp, photolysis rate was increased with pH increase; under daylight lamp, photolysis rate was decreased with pH increase. The photolysis rate constant of CA4P in water was smaller than that in methanol, respectively (k = 0.002 7 h-1 and k = 0.005 8 h-1). The effect of β-CD,HP-β-CD,Tween 80 on the photolysis rate constant of CA4P was different, the sequence was as follows :kblank (1 × 10-6L·mol-1·h-1) > k HP-β-CD (7 × 10-7L·mol -1·h-1) = kTween 80 (7 × 10 -7L·mol-1·h-1) > k β-CD (6 × 10-7L·mol -1·h-1). CONCLUSION: Light source, concentration, pH and solvent show important influence on photolysis kinetics of CA4P. β-CD, HP-β-CD and Tween 80 to some degree inhibits photolysis process of CA4P.