New potential antimalarial agents: therapeutic-index evaluation of pyrroloquinazolinediamine and its prodrugs in a rat model of severe malaria.
Tetra-acetamide pyrroloquinazolinediamine (PQD-A4) and bis-ethylcarbamyl pyrroloquinazolinediamine (PQD-BE) are new derivatives of pyrroloquinazolinediamine (PQD) and are being investigated as potential chemotherapeutic agents for the treatment of malaria. Comparative studies to assess the therapeutic indices of PQD-A4, PQD-BE, and PQD were conducted in Plasmodium berghei-infected rats following daily intragastric dosing for three consecutive days. Artesunate (AS), a standard drug for treatment of severe malaria, was used as a comparator. The minimum doses required to clear malaria parasitemia were 156 micromol/kg of body weight for AS and 2.4 micromol/kg for PQD, PQD-4A, and PQD-BE. The maximum tolerated dose (MTD) of AS was 625 micromol/kg, and its therapeutic index was calculated to be 4. The MTDs of PQD-A4, PQD-BE, and PQD were found to be 190, 77, and 24 micromol/kg, respectively, yielding therapeutic indices of 80, 32, and 10, respectively. Although PQD-A4 and PQD-BE are only half as potent as PQD based on their curative effects, the two new derivatives, PQD-4A and PQD-BE, are 8.0-fold and 3.2-fold safer, respectively, than their parent compound when they are dosed for three consecutive days. Oral PQD-A4 and PQD-BE are 44 to 70 times more potent on an mg basis than intravenous AS. As assessed from the therapeutic index over 3 days, PQD-A4, PQD-BE, and PQD administered orally are 20.0, 8.0, and 2.5 times safer than AS given intravenously. The results indicate that PQD-4A is a promising candidate for antimalarial treatment.
Xie
Lisa H
LH
Department of Pharmacology, Division of Experimental Therapeutics, Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, MD 20307-5100, USA. lisa.xie@na.amedd.army.mil
Li
Qigui
Q
Lin
Ai J
AJ
Smith
Kirsten
K
Zhang
Jing
J
Skillman
Donald S
DS
D000818:Animals; D000962:Antimalarials / Q000008:administration & dosage / Q000494:pharmacology*; D037621:Artemisinins / Q000494:pharmacology; D000077332:Artesunate; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D004353:Drug Evaluation, Preclinical; D008288:Malaria / Q000188:drug therapy; D020714:Maximum Tolerated Dose; D018512:Parasitemia / Q000188:drug therapy; D010962:Plasmodium berghei / Q000187:drug effects; D011355:Prodrugs / Q000008:administration & dosage; D011758:Pyrroles / Q000138:chemical synthesis* / Q000737:chemistry / Q000493:pharmacokinetics / Q000494:pharmacology* / Q000627:therapeutic use; D011799:Quinazolines / Q000138:chemical synthesis* / Q000737:chemistry / Q000493:pharmacokinetics / Q000494:pharmacology* / Q000627:therapeutic use; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D012717:Sesquiterpenes / Q000494:pharmacology; D013810:Therapeutic Equivalency
D000962:Antimalarials; D037621:Artemisinins; D011355:Prodrugs; D011758:Pyrroles; D011799:Quinazolines; D012717:Sesquiterpenes; C510736:bis-ethylcarbamyl pyrroloquinazolinediamine; C510735:tetra-acetamide pyrroloquinazolinediamine; D000077332:Artesunate