a non - aqueous pharmaceutical liquid suspension having improved bioavailability for oral administration comprises an active ingredient suspended in an edible , non - aqueous carrier vehicle such as an oil , wherein the active ingredient is in the form of controlled release particles containing the active ingredient and optionally an excipient in intimate admixture with at least one non - toxic polymer , the particles being coated with , distributed through or adsorbed onto said polymer , and the particles further having an average size in the range 0 . 1 to 150 microns and a predetermined release of active ingredient .