Summary:The N-[(4-cycloheptylaminopyrid-3-yl)sulfonyl]-N'-cycloheptyl urea, a neuroprotective agent, and 10 chemically related sulfonyl(thio)ureas were evaluated in the maximal electroshock seizure test in mice. This sulfonylurea, BM 27, and two stucturally related sulfonylthioureas, BM 11 and BM 34, emerged with a 50% effective dose (ED,,) of 2.87, 1.72, and 1.19 mg/kg, respectively. Their anticonvulsant profiles were found to be similar to that of phenytoin: active in the maximal electroshock seizure (MES) test and inactive in chemically induced seizures (pentetrazole, strychnine, bicuculline, picrotoxine, N-methyl-D,L-aspartic acid). These compounds exhibited a higher protective index and potency than those of phenytoin. Additional work remains necessary, however, to determine whether BM 27 is of clinical interest. Key Words: Sulfonylurea-Sulfonylthiourea-Epilepsy-Anticonvulsan-BM 34.
N-[ (4-cycloheptylaminopyrid-3-yl)sulfonyl]-N'-cycbheptyl urea, called BM 27, (Table 1) is a sulfonylurea that exhibits neuroprotective properties against normobaric hypoxia in mice (0.1-1 mg/kg) and cerebral ischemia in gerbils (1-2.5 mg/kg) (1). It is structurally related to torasemide (a loop diuretic) acting, as does furosemide (2), by the inhibition of the Na+ 2 HC1-K+ cotransporter of the thick ascending limb of Henle's loop (3). The central properties of BM 27 probably can be attributed to its ability to inhibit the astrocytic Na+ 2 HC1-K+ cotransporter (1). As furosemide blocks kainic acid-induced electrical discharges recorded from cortex (4), and in view of the antiepileptic properties attributed to the neuroprotective agents such as the antagonists of the N-methyl-D-aspartate (NMDA) and non-NMDA receptors (5-9), we investigated the anticonvulsant activity of BM 27 and some related substances. In this study, BM 27 and two sulphonylthioureas, BM 11 and BM 34, were selected to be tested in several classic anticonvulsant assays to define their pharmacologic profile.
METHODS
ChemistryAll compounds were synthesized as described previously (1). Their elemental analyses for C, H, N, and S were within 0.4% of the theoretic values. 'H-nuclear magnetic resonance (NMR) and IR spectra were in complete agreement with their chemical structure.
LipophilicityThe lipophilicity of compounds (log P) was measured at pH 7.4 and expressed as the logarithm of their partition coefficient in the n-octanollphosphate buffer system. The log P of a series of standards chosen in a wide range of log P values (from +0.16 to +2.0) was determined by using the shake-flask method (10). As reported (1,l l), a reverse-phase high performance liquid chromatography system was used to determine their capacity factor (log k') which corresponds to log (~-t,)/t,)] where t, is the drug retention time and t, is the void volume. A calibration curve calculated from log P and log k' of standards was used to interpolate the log P of the studied compounds.
Pharmacology
Anticonvulsant activityAll compounds were administered to OF1 male mice (22-25 g; Iffa-Credo, Les Onci...