Study of Perturbations Induced by a Barbituric, the Phenobarbital, on DSPC Multilamellar Liposomes

Multilamellar liposomes of distearoyl phosphatidyl choline in excess water condition, doped by the barbituric drug Phenobarbital, in molar ratios between 0 and 0.5, were studied by using differential scanning calorimetry, X-ray diffraction and electron microscopy. The results suggest that the drug interacts with the lipid headgroup region: in particular, at the higher concentrations investigated, an interdigitated "gel phase," with rigid chains, stiff and perpendicular to the lamellar planes, seems to be induced.