Forty years of beta-lactam research.

For more than 40 years the author has been involved in research in the field of beta-lactam antibiotics. Much of this work was concerned with the development of the semisynthetic penicillins, following the isolation of the penicillin nucleus, 6-aminopenicillanic acid. This work resulted in the introduction of a number of important antibiotics including methicillin, cloxacillin, flucloxacillin, ampicillin, amoxycillin, carbenicillin and ticarcillin. Many of these compounds also provided the incentive or the basis for studies of a more fundamental nature in cell biology and antibacterial chemotherapy. The following is the author's personal account of some of the studies in the beta-lactam field in which he has been involved.