Cheno-, Urso- and Deoxycholic Acid Spermine Conjugates: Relative Binding Affinities for Calf Thymus DNA

Cationic lipid polyamine amides (cholan-24-amides) have been prepared from chenodeoxycholic (3α,7α-dihydroxy), ursodeoxycholic (3α,7β-dihydroxy), and deoxycholic (3α,12α-dihydroxy) bile acids (5β-cholanes) by acylation of tri-Boc protected spermine. Their relative binding affinities for calf thymus DNA were determined using an ethidium bromide displacement assay. These lipopolyamine amides are synthetic vectors for non-viral gene delivery and models for lipoplex formation with respect to lipofection, a key first step in gene therapy.