A solid pharmaceutical composition for parenteral administration having an inner matrix containing at least one therapeutic agent, and a biodegradable, and water-impermeable coating covering part of the surface of said composition. The inner matrix disintegrates upon contact with animal tissue or tissue fluids. By providing a disintegratable and/or soluble inner matrix comprising the drug with a water-impermeable coating covering part of the surface of said composition, the rate of release of the drug can be controlled. The specific rate of release can be controlled by carefully designing the part of the surface which is not covered.