There is provided a pharmaceutical composition comprising cellulose obtained from algae, or a derivative of said cellulose, and an active pharmaceutical ingredient (e.g. from Type 2 and 4 BCS class), wherein the active pharmaceutical ingredient is in a predominantly amorphous form. Compositions of the invention find particularly utility as formulations comprising BCS Type 2 and 4 drugs, including NSAIDs or other drugs, that may be employed in the treatment of migraine or dysmenorrhea, as well as formulations comprising other poorly soluble active ingredients where rapid release in vivo is advantageous.