Ketoprofen-liposomes formulation for clinical therapy.

Lipid (L-α-phosphatidylcholine) was used in liposome-ketoprofen formulation to obtain vesicles systems characterized by a net positive charge along the liposomal surface. A careful analysis of vesicles formation and systems stability was made. Dynamic stability and specificity of liposomes disruption and prolonged release of ketoprofen was provided by steric effect accomplished on the vesicle surface by chitosan molecules, which were introduced into the system additionally. The retardation effect of the liposomes containing ketoprofen was tested in vitro and in vivo. The studies have shown that the liposomes containing ketoprofen obtained are characterized by a net positive charge and an average diameter of 1,287 nm for dialyzed solutions (pH 7.40). This formulation presents in vivo significant antinociceptive effects starting at 90 min, with a maximum intensity between 2 and 8 h, prolonged more than 10 h, and an analgesic activity within 3-4 h.