Binding of methamphetamine to serum albumin in various species in vitro

While drugs from experimental animals provide very important information, it is also true that data differ from species to species, and that data from experimental animals cannot be applied directly to humans. The binding parameters of serum albumin from various animal species and methamphetamine were investigated in vitro by the Scatchard method. The Scatchard plots for the binding of serum albumin and methamphetamine were classified into three patterns: straight lines for human and rat serum albumin; downwardly convex curves for bovine and rabbit serum albumin; and upwardly convex curves for horse, mouse and chicken serum albumin. Hill coefficients were calculated for binding in which the Scatchard plots were upwardly convex curves and for guinea pig serum albumin. The results suggested the existence of positive cooperativity between the methamphetamine binding sites on serum albumin from the horse, mouse, chicken and guinea pig. Furthermore, the process of methamphetamine binding to human serum albumin appears to differ from the process for all experimental animals except the rat, and there are also differences between the binding processes in the various experimental animals.