A composition comprising: (a) one to three bioactive agents; and (b) a vehicle comprising; (i) a modified liquid carrier, and (ii) an unmodified liquid carrier wherein the ratio by volume of the modified liquid carrier to the unmodified liquid carrier is between 0.00001:99.99999 to less than 0.01:99.99, that provide the composition with predictable sustained-release properties and wherein immediately after manufacture of the composition, said composition can be administered to a host such that the one to three bioactive agents is released to the host on a sustained basis.