Rra. Aboushaaban et al., ATOM LEVEL ELECTROTOPOLOGICAL STATE INDEXES IN QSAR - DESIGNING AND TESTING ANTITHYROID AGENTS, Pharmaceutical research, 13(1), 1996, pp. 129-136
Purpose. To design new antithyroid agents with less side effects, the
electrotopological-state (E-state) indexes of thiourylene moiety (S-N&
S) was utilized as a guideline to develop five acyclic thiourylene-typ
e compounds with reduced antioxidant property. Methods. These agents w
ere synthesized and screened for antithyroid activity in rats using I-
125-thiocyanate discharge technique. In addition, chemiluminescence st
udies on the activated polymorphonuclear leukocytes (PMNLs) were also
conducted to reveal antioxidant properties of the tested compounds. Re
sults. A linear relationship between the in vitro literature value of
the formation constants of thiourylene-type compounds with iodine (K-c
) and the S-N&S was observed and utilized in designing those agents. A
t least one of the compounds (abouthiouzine) was found to have a poten
tial value as an antithyroid agent. The relative efficacy of abouthiou
zine [1-n-butyl-3(isonicotinamido)-2-thiourea], after equimolar dose,
was 102% and 51.5% of that of propylthiouracil with respect to the rat
e of I-125-discharge and I-125-uptake, respectively. In addition, Chem
iluminescence studies on PMNLs revealed that abouthiouzine has slight
oxidant property. Such properties may provide advantages in avoiding t
he iatrogenic hypothyroidism and antithyroid-induced immunological rea
ctions. Conclusions. The E-state approach provides guidelines to econo
mize efforts and cost of designing new antithyroid drugs.