A controlled release pharmaceutical composition contains a number of spheroids, the spheroids containing a water-insoluble drug dispersed in a controlled release matrix. The matrix contains between 70% and 99.5% (by weight) of microcrystalline cellulose, between 0.5% and 4% (by weight) of a cellulose derivative and, optionally, up to 26% of a sugar or a sugar alcohol.The water insoluble drug must dissolve in water (pH 5) at 20.degree. C. to a concentration of less than 1.0 mg ml-1, preferably less than 0.5 mg ml-1. Preferred drugs are non-steroidal anti-inflammatory agents, especially fenprofen calcium, ibuprofen, ketoprofen, naproxen, diclofenac sodium, fenbufen, flurbiprofen, indomethancin, oxyphenbutazone, phenylbutazone or piroxicam.