Structure Activity Relationship of CHLOROQUINE

Chloroquine Inhibits parasite growth used for Prophylaxis and treatment of acute attacks of malaria caused by ·          Plasmodi...

Chloroquine Inhibits parasite growth used for Prophylaxis and treatment of acute attacks of malaria caused by

·         Plasmodium vivax,
·         P malariae,
·         P ovale and
·         susceptible strains of P falciparum; extraintestinal amebiasis [1]

SAR OF CHLOROQUINE

·         Addition of –CH3 group at position #2 will reduce the activity as in santoquine
·         Addition of –CH3 group at position #8 will reduce the activity / totally loss the activity
·         Introduction of any other groups into the quinoline nucleus will reduce the activity
·         Halogens “chlorine “at position #1 produce maximum activity
·         The presences of diethyl diamino pentane as a side chain is optimum for activity as in chloroquine
·         OH group addition in side chain at ethyl group the Hydroxy chloroquine, which is less toxic and produce the high blood levels but slightly lowers the activity
·         Addition of alpha diethylaminocresol in place of diethyl –diamino pentane results in production of amodiaquine, which is less toxics and also less effective as compared to chloroquine.
·         Any substitution at position 1,2,5,6 will lead to decrease the pharmacological activity.

References

1. Tatro DS, Borgsdorf LR. A to Z drug facts. Facts & Comparisons; 2003.