Solubilization of NSC-639829

Solubilization using pH combined with cosolvents, surfactants, and complexants are investigated for NSC-639829, an investigational anti-tumor agent. The intrinsic solubility of the drug is approximately 30 ng/ml and it has an ionizable dimethyl aniline group with an approximate base pK(a) of 5. Samples buffered at pH 1.0, 2.0, and 7.0 with various concentrations of the solubilizing agents were used to study the solubilization of NSC-629829 when present as charged and uncharged species. The solubilization of NSC-639829 was found to be much more effective when the drug was present primarily in ionized form. At pH values 1.0 and 2.0 where the surfactant (SLS) and complexant (SBEbetaCD) carried a negative charge enhanced solubilities of more than a million-fold were observed for the drug.