Cefazedone

A rapid, sensitive and simple high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was developed for determination of cefazedone in human plasma using metronidazole as internal standard (IS). The chromatographic separation was achieved on an Ultimate XB-CN column (2.1mm×150mm, 5μm) with an isocratic mobile phase of acetonitrile and 20mM ammonium acetate in 0.1% formic acid in water (15:85, v/v). Detection was performed using electrospray ionization in positive ion multiple reaction-monitoring mode (SRM), monitoring the transitions m/z 548.2→344.1 for cefazedone and m/z 172.2→128.1 for IS. Calibration curves were linear over a wide range of 0.20-401.12μg/mL for cefazedone in plasma. The lower limit of quantification (LLOQ) was 0.20μg/mL. The intra- and inter-day precisions were less than 7.2%. The average recovery of cefazedone was 90.8-91.0%. The validated method was successfully applied to the pharmacokinetic study of cefazedone in Chinese healthy volunteers following intravenous (IV) administration of 500, 1000 and 2000mg cefazedone injection.

Background: As a time-dependent antibiotic, the time of cefazedone concentration exceeds the minimum inhibitory concentration (MIC) is the key pharmacokinetic-pharmacodynamic (PK-PD) variable associated with the killing of pathogens. The purpose of the study was to evaluate the clinical regimen rationality of intravenous cefazedone sodium in the treatment of community-acquired pneumonia (CAP) by PK/PD study. Methods: Ten patients with mild to moderate CAP were enrolled to receive intravenous cefazedone sodium (2 g q12 h) for 7-14 days. Blood samples were collected in any day during day 5-7. Sputum specimens were collected before treatment for bacteria isolated, and susceptibility to cefazedone determined. PK-PD analysis was performed using the noncompartmental analysis of Phoenix WinNolin software (version 6.1, Pharsight Corporation, CA, USA). The maximal time above MIC (ƒT > MIC) was calculated, and its correlation with clinical efficacy was analyzed. Results: All 10 patients completed the study and 8 of them were cured. Six strains were isolated from patients before treatment (one for each patient) and all susceptible to cefazedone. Five patients of six in culture positive group were cured. All pathogens were cleared at the end of therapy. The MICs were between 0.25 and 1 mg/L. The main PK parameters were C max 175.22 ± 36.28 mg/L; T½ 1.52 ± 0.23 h; AUC (0-∞) 280.51 ± 68.17 mg·L -1·h -1 ; CL 7.37 ± 1.84 L/h; Vd 16.06 ± 4.42 L. The average ƒT > MIC was 55.45 ± 8.12%. Conclusions: Intravenous injection of cefazodone sodium with 2 g q12 h dosage regimen is used in the treatment of CAP caused by sensitive bacteria, either ƒT > MIC or clinical efficacy shows that such dosing regimen is reasonable.

Cephalosporin treatment in man has been associated with blood dyscrasias that include a time- and dose-related anemia, neutropenia, and thrombocytopenia, the hematopathology of which remains poorly characterized. A similar hematologic syndrome can be produced in dogs following daily intravenous injections of 540-840 mg/kg cefazedone or 400-500 mg/kg cefonicid for 1-3 months. Using this animal model, histologic and cytologic changes in blood, bone marrow, spleen, and liver were studied over the course of the cephalosporin-induced cytopenias. Peripheral blood cytologic observations included an absence, generally, of erythroid regenerative changes, increased numbers of macroplatelets, spherocytosis, erythroblastemia, and toxic neutrophil morphology. Interim and postmortem cytologic and histologic observations of bone marrow included hypoplastic and toxic changes, primarily in cytopenic dogs receiving high doses of cefonicid, and regenerative changes in hematopoietic tissue of affected cefazedone-treated animals. The latter included variable erythroid hyperplasia, increased megakaryocytes, and decreased marrow fat and was accompanied by evidence of extra-medullary hematopoiesis and increased hemosiderin and hemophagocytosis in liver and splenic tissue. The incidence and severity of these changes were dose-dependent, corresponded with the cytopenias observed peripherally, and, like the cytopenias, were fully reversible. These observations suggest that the hematologic syndrome associated with cephalosporin treatment in the dog has multiple toxicologic mechanisms, which include peripheral cytotoxic effects and bone marrow damage with depressed or ineffective hematopoiesis.