- BRL 17421, a novel beta-lactam antibiotic, highly resistant to beta-lactamases, giving high and prolonged serum levels in humans. Slocombe, B., Basker, M.J., Bentley, P.H., Clayton, J.P., Cole, M., Comber, K.R., Dixon, R.A., Edmondson, R.A., Jackson, D., Merrikin, D.J., Sutherland, R. Antimicrob. Agents Chemother. (1981)