Abstract: An improved process for dispensing a lipid soluble labile drug, i.e. 1,3-bis-(2-chloroethyl)-1-nitrosourea (BCNU) by diffusion through a silicone capsule implanted at a periocular site to an intraocular site within an animal body being treated with the drug, the improvements wherein the silicone capsule is provided with a tube sealed at the distal end thereof and provided with longitudinal slit cut through the tube wall inside the capsule for filling the capsule following implantation of the capsule, wherein the capsule is implanted surgically near the site being treated so that the tube is accessible for filling without further surgical procedures and wherein the drug is injected into the capsule through the tube in the form of a solution in a solvent which is non-toxic to the animal being treated, inert with respect to the drug dissolved therein and capable of diffusing from the capsule within 5 hours to leave a residue of the drug in the capsule.