pH modulates cisplatin toxicity

Cisplatin in normal saline of pH 2.5 caused haemolysis of rat erythrocytes, whereas cisplatin in normal saline of pH 3.5 did not. Even a difference of 0.2 pH units appeared to be of significant importance: haemolysis of rat erythrocytes was observed with cisplatin in saline of pH 3.0 but not with cisplatin in saline of pH 3.2. The LD in mice was 15.4 mg/kg for cisplatin in saline of pH 2.5 versus 24.0 mg/kg for cisplatin in saline of pH 3.5. Experiments with cisplatin should include careful control of pH.