title: Zero-crossing derivative spectrophotometry for the determination of mixtures of cephaloridine and cephalothin in pure and dosage forms.
abstract: First- and second-derivative spectrophotometry, with a zero-crossing technique of measurement, has been used for the quantitation of two-component mixtures of cephaloridine and cephalothin Na, which are cephalosporins with closely overlapping spectral bands. Beer's Law is followed for up to 28 and 36 micrograms/mL of cephaloridine in the first- and second-derivative modes, respectively, and up to 36 micrograms/mL of cephalothin Na in both modes. Detection limits at the 0.05 level of significance were calculated to be 0.13 and 0.37 micrograms/mL of cephaloridine and cephalothin Na, respectively, in the first-derivative mode, and 0.25 and 0.29 micrograms/mL, respectively, in the second-derivative mode. The recovery of these antibiotics in mixtures of injectable dosage forms is also reported.
authors.affiliation: Universitá degli Studi-Bari, Dipartimento di Chimica, Italy.
authors.forename: B
authors.initials: B
authors.lastname: Morelli
mesh_terms: D002509:Cephaloridine / Q000032:analysis*; D002512:Cephalothin / Q000032:analysis*; D055598:Chemical Phenomena; D002621:Chemistry; D013056:Spectrophotometry, Ultraviolet
chemical_list: D002509:Cephaloridine; D002512:Cephalothin