Figure 1.

pH-dependent solubility of MDZ. Saturation concentration of MDZ in Britton-Robinson (BR) buffer alone and in BR buffer combined with 10% solubilizer hydroxypropyl-β-cyclodextrin (HPβCD), randomly methylated-β-cyclodextrin (RMβCD), or hydroxypropyl-γ-cyclodextrin (HPγCD) depended on pH. At a pH < 5 all tested CD derivatives increased the solubility of MDZ to a similar degree compared with the solubility in BR buffer alone. Above pH 5 solubility of MDZ was below 10 mg ml⁻¹. Britton-Robinson (BR) buffer (); BR buffer + 10% RMβCD (); BR buffer + 10% HPβCD (); BR buffer + 10% HPγCD ()