Liposomes containing dopamine entrapped in response to transmembrane ammonium sulfate gradient as carrier system for dopamine delivery into the brain of parkinsonian mice.

The active loading of liposomes with dopamine in response to an ammonium sulfate gradient was studied. This method can be regarded as a mean to more efficiently improve the liposomal dopamine/lipids ratio in comparison to conventional methods of liposome preparation. Trapping efficiency of dopamine into liposomes exhibiting a transmembrane ammonium sulfate gradient was shown to be dependent on liposome lipid composition, lipid concentration and temperature. Dopamine-containing liposomes with alpha-tocopherol in the lipid bilayer were shown to be stable at least for three weeks. It has been found that intraperitoneal (i.p.) administration of conventionally prepared dopamine-containing liposomes as well as liposomes with increased dopamine/lipid ratio may efficiently suppress the expression of parkinsonian symptoms in C57BL/6 mice with experimental parkinsonian syndrome. On the other hand, only through increasing of liposomal dopamine/lipid ratio the complete compensation of dopamine deficiency in the mice brain was achieved. The obtained data may be considered as biochemical evidence in favor of liposomes' ability to act as a carrier system for the delivery of dopamine into the brain.