An injectable, nonaqueous suspension including at least one therapeutic agent suspended in a single component vehicle. The single component vehicle is a single amphiphilic material, such as a polyethoxylated castor oil or derivative thereof, a polyoxyethylene alkyl ether, a polyoxyethylene sorbitan fatty acid ester, a polyoxyethylene stearate, a block copolymer of polyethylene oxide-polypropylene oxide-polyethylene oxide, a block copolymer of polypropylene oxide-polyethylene oxide-polypropylene oxide, a tetra-functional block copolymer of polyethylene oxide-polypropylene oxide, or a tetra-functional block copolymer of polypropylene oxide-polyethylene oxide. A dosage kit that includes the injectable, nonaqueous suspension and a method of administering the injectable, nonaqueous suspension are also disclosed.