Solubilizing Coelenterazine in Water with Hydroxypropyl-β-cyclodextrin

Abstract

Coelenterazine is poorly soluble in water except at alkaline pH values that promote auto-oxidation. The solubility is markedly increased by adding hydroxypropyl-β-cyclodextrin in a neutral buffer solution, the solubilization being most effective in the pH range of 6.5 to 7.0. The concentration of coelenterazine dissolved in a pH 7.0 buffer containing 50mM hydroxypropyl-β-cyclodextrin was about 280-fold higher than that without the additive.