LIPOPHILICITY OF TEICOPLANIN ANTIBIOTICS AS ASSESSED BY REVERSED-PHASE HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY - QUANTITATIVE STRUCTURE-PROPERTY AND STRUCTURE-ACTIVITY-RELATIONSHIPS

Structure-lipophilicity relationships of a large series of 63-COX teic oplanin antibiotic derivatives were examined, by correlating their cap acity factors (log k(w)), measured through reversed-phase highperforma nce liquid chromatography on Deltabond C-8 stationary phase, with some computed molecular properties such as fragmental log P constants (pi( X)), molecular volumes (V-x) and factors imparting hydrophilicity (e.g . amino groups in the X chain, nN). A number of equations were derived which demonstrate that variations of log k(w) are mainly related to c hanges in bulk (modelled by V,) and polarity (primarily modelled by nN ) of X chains of teicoplanin derivatives. QSAR analysis revealed that in-vitro activity against E. coli increases as lipophilicity decreases and isoelectric point increases.