RESUMO
The stability of cefazolin 1 g in metronidazole 500 mg/100 mL at 8 degrees C was studied for use as an IV admixture. The commercially available injection of cefazolin sodium 1 g vial was diluted to 5 mL with 0.9% sodium chloride injection and added to metronidazole 500 mg/100 mL. Following dilution of 2 mL to 100 mL with water, 1-mL aliquots were transferred to glass vials, refrigerated at 8 degrees, and assayed for cefazolin and metronidazole concentration at 0, 1, 2, 4, 8, 12, 24, 36, 48, and 72 hours after preparation. The concentration of cefazolin and metronidazole was determined by a stability-indicating high-performance liquid chromatographic method. The range of concentration was determined to be within 5% of the 0-hour mean concentration. Over the 72-hour period, the mean concentration of cefazolin at all assay times was within 98.4 to 101.0% of the initial concentration. The mean concentration of metronidazole at each assay time was 96.9 to 104.9% of the initial concentration. Cefazolin sodium 10 mg/mL and metronidazole 5 mg/mL, prepared by adding reconstituted cefazolin to a glass bottle of metronidazole ready-to-use solution, were stable for 72 hours when stored at 8 degrees C.
Assuntos
Cefazolina/química , Metronidazol/química , Refrigeração , Cromatografia Líquida de Alta Pressão , Combinação de Medicamentos , Estabilidade de Medicamentos , Fatores de TempoRESUMO
The stability of cefotaxime and metronidazole in i.v. admixture at 8 degrees C was studied. The commercially available injectable formulation of cefotaxime sodium 1 g was diluted to 5 mL with 0.9% sodium chloride injection and added to metronidazole injection 500 mg/100 mL. A 2-mL sample was removed and diluted to 100 mL with water. Thirty 1-mL portions were transferred to glass vials and refrigerated at 8 degrees C. At 0, 1, 2, 4, 8, 12, 24, 36, 48, and 72 hours after the admixture was prepared, the vials were removed, placed in a refrigerated autosampler, and assayed for cefotaxime and metronidazole concentrations by stability-indicating high-performance liquid chromatography. Over the 72-hour study period, the concentration of cefotaxime remaining at all assay times was 95.91-101.13% of the initial concentration. The concentration of metronidazole remaining at each assay time was 93.08-102.19% of the initial concentration. Cefotaxime sodium 10 mg/mL and metronidazole 5 mg/mL were stable for 72 hours at 8 degrees C in an i.v. admixture prepared from commercially available injectable formulations.
