Trifluoroacetyl
primaquine (M-8506), 6-methoxy-5-trifluoroacetyl-8-(4-methyl-butyl-amino)-aminoquinoline
oxalate, synthesized by the Institute of
Parasitic Diseases was compared with
primaquine for tissue schizontocidal action and acute ig LD50. In P yoelii sporozoite infected mice, the protection rates with ig
M-8506 5, 10 and 20 mg (base)/kg on the day of
infection were 56.7, 87.2 and 100%, respectively. These were comparable to the protection rates with
primaquine 5, 10 and 20 mg(base)/kg (54.4, 90.8 and 100%, respectively). The radical curative effect was conducted in P cynomolgi sporozoite infected Macaca mulatta. Since im
pyronaridine 10 mg/kg b.i.d. (6 h apart) completely eliminated the parasites in monkeys infected with erythrocytic stages of P cynomolgi, the tissue schizontocidal activities of
M-8506 and
primaquine were observed by im administration of
pyronaridine 10 mg/kg b.i.d. on d 1.
M-8506 at 0.75, 1.5 and 3 mg/(kg.d) x 3d plus
pyronaridine were given to 7, 4 and 2 infected monkeys with
parasitemia respectively. All the monkeys, except one receiving 0.75 mg/(kg.d) x 3 d, were radically cured.
Primaquine 0.75, 1.5 and 3 mg/(kg.d) x 3 d were administered to 3, 3 and 2 monkeys respectively. Two monkeys receiving
primaquine 0.75 mg/(kg.d) x 3 d relapsed on d 42. The
parasitemia reappeared earlier than that treated with
M-8506 0.75 mg/(kg.d) x 3 d and relapsed on d 62. Because
M-8506 is less toxic than
primaquine in mice and more effective in radical treatment of simian
malaria, further studies on trifluoroacetyl
primaquine are worthy to be considered.