A fusogenic liposome composition for delivering a liposome-entrapped compound
into
the cytoplasm of a target cell is described. The liposomes have an outer surface
coating of chemically releasable hydrophilic polymer chains which shield hydrophobic
polymers on the liposome outer surface. Release of the hydrophilic polymer chains
exposes the hydrophobic polymers for interaction with outer cell membranes of the
target cells to promote fusion of the liposome with the target cells. Also disclosed
is a method for using the composition to deliver a compound to target cells, and
a method for selecting suitable hydrophobic polymers for use in the composition.