Toxicity of chloroprocaine and sodium bisulfite on human neuroblastoma cells

The effects of commercial and crystalline solutions of chloroprocaine (CP) (1.6 X 10(-3)-0.4 X 10(-3)M) and sodium bisulfite (SB) (0.8 X 10(-3)-0.08 X 10(-3)M) were studied on the multiplication of human neuroblastoma cells. These cells were chosen because of putative neurotoxicity associated with CP; cell multiplication (measured as colony-forming ability-CFA) was studied because CFA is a reliable in vitro test for drug toxicity at the cellular level. CFA was dramatically reduced (86%) after 20-hr exposure to commercial solutions of CP. Shorter exposure times (3 hr) resulted in a marginal toxic effect (32%). At similar concentrations and after 20-hr exposure time, CP crystalline solutions induced a 37.5% inhibition that decreased with decreased time in culture. Sodium bisulfite reduced cell multiplication to a degree that varied with different samples of SB. With a 3-hr exposure time, CFA was reduced 72-92% by SB-1 and 57-72% by SB-2. The variability of SB toxicity and the difference in toxicity with commercial and crystalline solutions of CP are discussed in terms of possible clinical toxicity.