Solubilization of some steroids in aqueous solutions of a steroidal nonionic surfactant

The solubility of testosterone, methyltestosterone, and testosterone propionate in aqueous solutions of unpurified and partially purified ethoxylated cholesterol was determined. The solubilizing capacities of both the surfactant samples were of the order: testosterone propionate > methyltestosterone > testosterone. The UV spectral characteristics of the three steroids in aqueous solutions of both the surfactant samples were similar to those in various polyethylene glycols. The spectral evidence suggests a mechanism of solubilization involving association of the steroid with the polyoxyethylene portion of the surfactant.