Studies on the permeability of drugs through vesical wall. The fifth report: experiences with intravesical formalin administration.

When some drug is injected into the bladder, it has been found to permeate through the bladder wall, and appear in the serum. Similarly, formaldehyde, which is in some clinical cases injected into the bladder on hemostatic purposes, could produce side effects if a large part of its injected dose is transferred into the serum. We, therefore measured the transfer of the agent into the serum in both experimental animals and human patients. Formaldehyde was found to be transferred into the serum through the bladder of rabbits with cystitis, but only a trace of it appeared in the serum through the normal bladder. The injection of 10 ml of a 10% solution of formaldehyde to rabbits with cystitis was followed by a peak level of 8 gamma/ml in the serum. Judging from this level, the same amount injected to humans would not be high enough to cause any particular problems. In the actual study, the formaldehyde level in the serum of human patients was not detectable by the assay method used.