Intravesical oxybutynin chloride has demonstrated its efficacy in children with neurogenic bladder and urinary incontinence refractory to oral anticholinergic agents. We developed a 205 microg/ml oxybutynin chloride solution in accordance with the specifications of the European Pharmacopeae. To guarantee quality, we assessed and validated formulation, the preparation process, and packaging. The solution was obtained by disolving oxybutynin chloride in 0.9% saline and sterile filtration. The solution was then packaged in syringes. Physical properies for intravesical instillation were met: pH 5.76 +/- 0.03, osmolality 281 mosmol/kg. The unit dose package guarantees sterility of the solution until use. The medication is given by adapting the syringe on the Luer Lock exteremity of the urinary catheter. The solution remains stable up to one month at 4 degrees C.