Penicillins and cephalosporins. Physicochemical properties and analysis in pharmaceutical and biological matrices.

Penicillins and cephalosporins belong to the most prescribed antibiotics. Despite the relatively extended knowledge of these drugs, the qualitative and quantitative analysis of the compounds still gives rise to many problems. These difficulties are due to the chemical instability of the common beta-lactam nucleus, the minor differences in chemical structures between the analogues, and the complex and relatively fast degradation of the compounds in aqueous solutions. In this review a compilation of the physicochemical properties, the degradation routes and methods for analysis of these substances in biological and other matrices is presented.