Curcumin preparation

Curcumin was prepared as previously described. Briefly, hydroxypropyl-γ-CD was dissolved to a concentration of 112 g/L in 0.18 M sodium hydroxide solution. Curcumin (Curcumin C3 Complex; Sabinsa Corp., East Windsor, NJ, USA) was added to a concentration of 15 g/L. The solution was agitated, and after complete dissolution of curcumin, the pH was adjusted to 6.0 with a mixture of acids. The solution was filtered and filled aseptically into sterile vials that were then capped and sealed. The recovered CDC solution contained 12 g/L curcumin and 93 g/L CD in 20 mM sodium citrate in a total of 100 mM NaCl solution. Endotoxin content was <1.8 IU/ml as measured by the Limulus amoebocyte lysate gel clot method. The CDC solution was stored at 2–8°C and protected from light. The CD vehicle was prepared in the same way but without the addition of curcumin (24, 25).