is made by one of three methods 1 a porous material such as polypropylene is impregnated with at least one microbicidal agent it is then coated with a hydrophilic polymer which in response to contact with urine swells causing the leaching out of the microbicidal substance 2 a porous material such as high density polyethylene is impregnated with a hydropholic polymer and at least one microbicidal agent 3 the microbicidal tube is made by compounding and co extruding a polymer such as silicone with at least one microbicidal agent and then coated with a hydrophilic polymer the solution of the additives and the polymeric material is allowed to react for a suitable length of time in the presence of solvent or solvents the usual solvents in the preparation of the microcidal tube are ethanol and dimethyl sulfoxide at the end of the reaction time the microbicidal tube is dried by conventional methods and sterilized with ethylene oxide eto the specific antimicrobial substance to be used is left to the choice of the manufacturer however such substance must readily be compounded into polymers or adhere to the porous polymeric material which in turn will absorb the substance the biocidal additives can be selected from a very large group of commercially available antibiotics drugs antiseptics etc some examples of the common active agents that can be incorporated into the microcidal tube are penicillin tetracycline triclosan nalidixic acid sulfamylon amphotericin b nonfloxacin haloprogin gentamicin chlorhexidine clotrimazol tolnaftate polymyxin parachlorometaxylenol pyrithione hexachlorophene nitrofurazone nitrofurantoin chlorixin and many others microbicidal agents may be incorporated either singly or in various combinations the microcidal tube may be inserted inside the outlet tube during normal manufacturing conditions and there will be no loss of the biocidal activity since.