Ampicillin tetramer

Fig. 10. Time course of formation of ampicillin tetramer in 10% solid circles) and 20% W/V open circles) aqueous solutions of ampicillin sodium kept at 22 ""C. (Larsen and Bundgaard 1977)...

Fig. 7. Fractionation by anion exchange chromatography of 1 ml portions of a 20% aqueous solution of ampicillin sodium (initial pH 8.5) kept at 22 °C for the specified periods. The DEAE-Sephadex A-25 column was eluted with 0.05 M phosphate (pH 7.4), with a linear sodium chloride gradient. Peak identities A, ampicillin B, a-aminobenzylpenicilloic acid C, dimer D, mixture of a trimer having a closed -lactam ring and a dimer having an open j -lactam ring E, tetramer /% mixture of a tetramer having an open j -lactam ring and a pen-tamer with an intact j -lactam ring G, hexamer H, octamer. (Bundgaard and Larsen 1977)...

In the studies reporting on the immunologic and especially the eliciting properties of ampicillin polymers, which are described subsequently, a mixture of polymeric materials has apparently been used and no individual dimers and polymers have yet been tested. A priori the dimer molecule should be expected to be a poor elicitor of penicilloyl-specific reactions because it contains only one penicilloyl group. In contrast, the tetramer with its three penicilloyl groups might be expected... 

---