The aim of this thesis was to develop novel surfactants, able to self-assemble into micelles and to solubilize insoluble drugs intented for intravenous injection. Natural-based surfactants were synthesized and their physico-chemical properties were evaluated. In addition, their in vitro and in vivo toxicity were evaluated. Their drug solubilization abitity was also investigated. Three surfactant classes were evaluated. They were composed of a hydrophobic moiety, such as cholesterol, bile salts or lipids, bonded to a hydrophilic moiety, deriving from amino acids, such as lysine, glutamine or glutamic acid, via an amide bond.The influence of surfactant hydrophobic moiety flexibility on drug solubilization ability was evaluated. This study evidenced that solubilization efficiency is related to the surfactant hydrophobic moiety flexibility. The use of surfactants with flexible and saturated lipidic moieties increased drug water solubility with a drug loading of 46 % (w/w). Saturated lipid-based surfactants exhibited a better solubilization efficiency, in comparison with steroid-based surfactants or poly-unsaturated-based surfactants. Toxicity studies evidenced the relation between surfactant chemical structure and their toxicity, in particular with cell membranes. The introduction of double bond in cis configuration in surfactant lipidic moiety decreased their interaction with cell membranes and thus their toxicity. In addition, this chemical modification also decreased their solubilization ability. To develop novel surfactants, it is thus necessary to take into account drug solubilization ability and toxicity of surfactants.
Natural-based surfactants for drug solubilization : synthesis, physico-chemical properties and toxicity