1997 Volume 45 Issue 12 Pages 1970-1974
Bis-quaternary ammonium compounds (bis-QACs), 4, 4'-(α, ω-polymethylenedithio)bis(1-alkylpyridinium iodide)s (4DTBP-m, n), which have 3 to 10 carbon atoms in the connecting methylene chain (m) and 8 to 18 carbon atoms of the N-alkyl chain (n), were synthesized. 4DTBP-6, 12 exhibited a wide antimicrobial spectrum against gram-positive and gram-negative bacteria and fungi. The activity was stronger than those of N-dodecylpyridinium iodide (P-12), benzyldodecyldimethylammonium chloride and 2-(4-thiazolyl)benzimidazole. The bactericidal activities of 4DTBP-m, n were scarcely affected by the lengths of the alkyl chain and methylene chain. The bis-QAC that showed the highest activity was 4DTBP-6, 8 (nimimum inhibitory concentration (MIC)=1.6 μM, minimum bactericidal concentration (MBC)=2.6 μM), and its activity was about 10 times that of N-hexadecylpyridinium iodide (P-16), which was the most active in the P-n series. In addition, 4DTBP-6, 12 showed a high bactericidal activity in the ranges of pH 5 to 8.5 and 10 to 40°C, in contrast to mono-QACs. The bis-QACs synthesized in this study have excellent bactericidal properties.
