With the exception of an aqueous oral solution used in low-dose phase 1 study, powder-filled hard gelatine capsules of similar qualitative composition, ranging in dose from 5 to 300 mg, and prepared from powder blend formulation series A (25% pregabalin w/w), B (44.44% pregabalin w/w) or C (75% pregabalin w/w) have been used throughout clinical development.