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

The active loading of liposomes with dopamine in response to an ammonium su lfate gradient was studied. This method can be regarded as a mean to more e fficiently improve the liposomal dopamine/lipids ratio in comparison to con ventional methods of liposome preparation. Trapping efficiency of dopamine into liposomes exhibiting a transmembrane ammonium sulfate gradient was sho wn to be dependent on liposome lipid composition, lipid concentration and t emperature. Dopamine-containing liposomes with a-tocopherol in the lipid bi layer were shown to be stable at least for three weeks. It has been found t hat intraperitoneal (i.p.) administration of conventionally prepared dopami ne-containing liposomes as well as liposomes with increased dopamine/lipid ratio may efficiently suppress the expression of parkinsonian symptoms in C 57BL/ 6 mice with experimental parkinsonian syndrome. On the other hand, on ly through increasing of liposomal dopamine/lipid ratio the complete compen sation of dopamine deficiency in the mice brain was achieved. The obtained data may be considered as biochemical evidence in favor of liposomes' abili ty to act as a carrier system for the delivery of dopamine into the brain.