A continuous intravesical drug delivery system for the rat.
 We describe a self-contained system for the continuous infusion of drugs into the rat urinary bladder.
 A reversible model of hydronephrosis is used to prepare one renal unit for nephrostomy tube placement.
 An 0.8 mm.
 silastic nephrostomy tube is introduced into the hydronephrotic kidney via a 16 gauge angiocath.
 The nephrostomy tube is then connected to an Alzet mini osmotic pump which is implanted in a subcutaneous location.
 The ability of this system to deliver a continuous dose of a test agent into the bladder was evaluated.
 Pumps were filled with a 1% solution of methylene blue in phosphate buffered saline.
 Following pump implantation, urinary samples were collected on a daily basis and subsequently analyzed for their concentration of methylene blue.
 At the completion of the experiment, specimens of the kidney, ureter, and bladder were histologically examined.
 Results demonstrated an average of 102% recovery of the theoretically delivered dose over a 14-day period.
 Renal histology demonstrated chronic inflammatory changes at the site of nephrostomy tube placement.
 No upper or lower tract urothelial changes were identified.
 This model provides a system for the continuous delivery of drugs in the rat urinary tract and results in no histological alteration to the lower urinary tract.
