Quantitative Relationships Between Structure, Aggregation Properties and Antimicrobial Activity of Quaternary Ammonium Bolaamphiphiles

Abstract

QSAR analysis employing Kubinyi's bilinear model was applied to examine the relationship between the structure (characterized by the lengths of the terminal hydrocarbon chain, m, and of the hydrocarbon spacer chain, y), lipophilicity (characterized by the chromatographic parameter Rm and aggregation properties expressed through the critical micellar concentration cK), and antimicrobial activity (characterized by the minimum inhibition concentration, MIC) of quaternary ammonium bolaamphiphiles. The log cK = f(m) dependence was found to be linear whereas the log (1/MIC) = f(m), log (1/MIC) = f(y), log (1/MIC) = f (log cK) and log (1/MIC) = f(Rm) dependences were nonlinear. The effect of the hydrophobic terminal chains (m) and of the hydrophobic spacer chain (y) on the aggregation properties and on the biological activity of the substances was studied.

Gemini-Tenside

“…Es stellte sich die Frage, ob Gemini-Tenside der allgemeinen Struktur 49 (siehe Tabelle 2) eine ähnliche biologische Wirksamkeit aufweisen. [65] In einer erstaunlich umfangreichen Studie wurde die Kettenlänge m zwischen 6 und 16 und die Spacerlänge n zwischen 2 und 8 variiert, was in Summe 45 Verbindungen ergab. Für diese Gruppe von Gemini-Tensiden wurden die minimalen Inhibitorkonzentrationen (minimum inhibitory concentrations (MICs), definiert als die niedrigste Konzentration eines antibakteriellen Wirkstoffs, bei der nach 24 h Inkubation bei 37 8C das sichtbare Wachstum gehemmt wird) gegenüber E.-coli-Bakterien bestimmt.…”

“…[65] Aus den Ergebnissen lassen sich folgende Verallgemeinerungen ableiten: a) Kurzkettige Verbindungen (m 6) sind nicht wirksam. b) Kurze Spacer führen zu niedrigeren MIC-Werten.…”

The formation of host–guest complexes between surfactants and cyclodextrins

“…The ability of geminis to make organic compounds soluble in water makes them useful for applications in different fields such as drug formulations [272] and waste water treatment [231]. Other interesting and promising applications involve skin care [273], gene delivery vectors [274,275], antimicrobial effect [276], skin permeation enhancers [277], analytical methods [278,279], and synthesis of gold nanoparticles with tunable longitudinal surface plasmon resonance [280,281].…”

Structural Changes of DPPC Bilayers Induced by Gemini Surfactant

“…Symmetric dicationic (msm) surfactants with a short spacer group exhibit also signicantly higher antimicrobial activity (even 100 times higher) than the monomeric surfactants commonly used as germicides (dodecylbenzyldimethylammonium bromide or 2-ethoxycarbonylpentadecyltri-methylammonium bromide) [15,16]. This group of surfactants has also promising applications in preparation of cosmetics, emulsiers, personal care products etc.…”