title: Antimalarial activity of the optical isomers of chloroquine diphosphate.
abstract: Optically pure d- and l-Chloroquine Diphosphate were examined for their efficacy against Plasmodium berghei in mice. The d-enantiomer is significantly more effective than the corresponding l-enantiomer, and in subcurative doses the d-enantiomer is also signficantly more active than the racemate. This increased activity  has however no influence upon Chloroquine-resistant strains of P. berghei. The LD50 in non-infected mice is higher for the d-enantiomer than for either the racemate or the l-enantiomer when mice were treated orally one and 4 times. These differences in efficacy and toxicity between the d- and l-enantiomer of Chloroquine are however not as pronounced as those found for the enantiomers of many other drugs and furthermore these differences are limited to subcurative doses.
mesh_terms: D000818:Animals; D002738:Chloroquine / Q000008:administration & dosage* / Q000494:pharmacology / Q000633:toxicity; D007928:Lethal Dose 50; D008288:Malaria / Q000188:drug therapy*; D051379:Mice; D010962:Plasmodium berghei / Q000187:drug effects*; D013237:Stereoisomerism
chemical_list: D002738:Chloroquine