Properties of Organic Acid Solutions which Determine their Irritability to the Bladder Mucous Membrane and the Effect of Magnesium Ions in Overcoming this Irritability

Abstract

Suby, Suby. and Albright investigated various organic acid solns. pertaining their irritability to the bladder mucous mem-brane and their capacity to dissolve phosphatic urinary calculi. The first method which consisted in dripping the test soln. over the lower eyelid of rabbits, was abandoned as unsatisfactory. Dogs as test animals were found to be impractical. Rabbits proved to be satisfactory. A 2-way No. 22 or No. 24 soft rubber catheter was used; to the inlet was connected a reservoir with the test soln. and a Murphy drip bulb; the outlet was connected to a simple constant drainage. The bladder was lavaged with the test soln. at the rate of 60 to 80 drops per min. for a period of 4 hrs. At the end of the 4 hr. period the rabbit was killed and autopsy was done. The results obtained with various solns. revealed the following. Normal saline caused no bleeding and the bladder mucous membrane remained normal. Identical findings were obtained with distilled water. Hypertonic salt soln. caused edema. Citric-acid-sodium-citrate soln. at pH 4.0 caused bleeding. A simihfr soln. at pH 5.0 also caused damage although to a lesser degree. K acid phthalate at a pH of 4.0, acetic acid-acetate soln. at pH 4.0 and levulinic acid caused changes in the mucosa. Addition of MgSO4 to the citric acid citrate combinations markedly reduced the irritability. A soln. of citric acid (monohydrate) (32.3g), magnesium oxide (anhydrous) (3.8g). sodium carbonate (anhydrous) (4.4g), and distilled water (ad 1.000 cc) proved to be effective in dissolving Ca phosphate stones and was of low irritability.[long dash]Erwin Ncter.