Self-Association of Penicillins in Aqueous Solution as Revealed by Gel Filtration Chromatography

概要

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The self-association of penicillin G (PCG) and penicillin V (PCV) in 0.15 M potassium chloride solution has been investigated by frontal gel filtration chromatography (GFC) on Sephadex G-10 columns at 25℃. Analysis of the centroid volume, V_c, of a GFC profile yields the monomer concentration of a penicillin and the weight-average aggregation number, n_w. No critical micelle concentration is observed in the V_c vs. concentration profile for PCV. The n_w value for PCV is 2 at low concentrations and gradually increases with increasing concentration. PCG forms dimers only below 0.06 M, and provides useful GFC data for the investigation of dimerization. The dimerization constants of PCG and PCV are also evaluated from the concentration dependence of the derivative peak position at the trailing boundary. Stepwise aggregation constants, obtained from non-linear least-squares fitting of the centroid volume data, satisfactorily reproduce observed derivative chromatograms, and are used for calculations of the aggregate size distribution of PCV. The structure-association relationship and the effect of self-association on the bactericidal activity and chemical stability of the penicillins are discussed.
公益社団法人日本薬学会の論文
1994-04-15