A method of coating spherical particles of a beta blocker compound which is based on (a) determining the surface area of a weighed sample of said spherical particles (b) determining the weight of coating material per surface area unit of spherical particles that will provide a desired release profile for said beta-blocker (c) determining the surface area of a subsequent batch of spherical particles containing the same beta (d) coating the subsequent batch of spherical particles with the coating applied in step (b) to provide a coating having substantially the same weight of coating material per surface area unit of spherical particles as determined in step (b).
