title: Irritant actions of unphysiological pH values. A controlled procedure to test for topical irritancy.
abstract: The abdominal skin of juvenile white mice was used. Topical application was accomplished by intracutaneous injection. The solutions tested were thoroughly standardized. By using a special buffer system, a mixture of histidine glutamate and lysine glutamate, each pH value could be tested with the same buffer capacity. The pH values varied from pH 3 to pH 11, the solutions being always iso-osmolalic with plasma. Two criteria were used to judge the irritancy: (a) the edematous reaction for the first 6 h and (b) the macroscopic aspect after 24 h. A very special procedure enabled us to obtain objective numerical values for criterion (a). The results disclose that irritation becomes manifest at pH 4 and pH 10, becomes clear-cut with pH 3 and even more so with pH 11, and depends strongly on the buffer capacity employed. With two substances-amidosulfuric acid and (tri) sodium phosphate--it was exemplified how the procedure could be used to routinely screen for topical irritancy in an informative, inexpensive and decent manner.
mesh_terms: D000818:Animals; D002021:Buffers; D004487:Edema / Q000139:chemically induced; D006863:Hydrogen-Ion Concentration; D007509:Irritants; D008297:Male; D051379:Mice; D009336:Necrosis / Q000139:chemically induced; D012871:Skin Diseases / Q000139:chemically induced* / Q000473:pathology
chemical_list: D002021:Buffers; D007509:Irritants