Sustained-release bactericidal cannula.

Methods of making sustained release bactericidal cannulas or catheters through which aqueous biological fluids can pass. The bactericidal cannula for catheter including a tube having an inner surface, defining and interior lumen, and an outer surface. The tube has a polymeric matrix and antibacterial agent residing within at least a portion of the polymeric matrix. The polymeric matrix includes cured silicon rubber and the antibacterial agent is a finely divided nitrofuran compound which is soluble in water and effective to prevent proliferation of certain bacteria in an otherwise growth supporting aqueous environment when dissolved in the aqueous environment to the limit of its solubility therein at 37 DEG C. The solubility of the nitrofuran compound is about 0.2% by weight or less at a pH of about 6 and a temperature of about 25 DEG C. A portion of the polymeric matrix proximate the outer surface includes an amount of from about 10 to about 60% by weight of the nitrofuran compound and the amount of the nitrofuran compound and the solubility thereof cooperate to provide a potential for a sustained release diffusion thereof for a period of not less than about three weeks during normal use of the cannula within the human body.