A nonaqueous, single-phase vehicle that is capable of suspending an
active agent. The nonaqueous, single-phase vehicle includes at least one
solvent and at least one
polymer and is formulated to exhibit phase separation upon contact with an aqueous environment. The at least one
solvent may be selected from the group consisting of
benzyl benzoate, decanol, ethyl hexyl lactate, and mixtures thereof and the at least one
polymer may be selected from the group consisting of a
polyester, pyrrolidone, ester of an unsaturated
alcohol,
ether of an unsaturated
alcohol, polyoxyethylenepolyoxypropylene block
copolymer, and mixtures thereof. In one embodiment, the at least one
solvent is
benzyl benzoate and the at least one
polymer is
polyvinylpyrrolidone. A stable, nonaqueous suspension formulation that includes the nonaqueous, single-phase vehicle and an
active agent, and a method of forming the same, are also disclosed.