title: Stability of imipenem and cilastatin sodium in total parenteral nutrient solution.
abstract: The chemical stability and compatibility of imipenem-cilastatin sodium (Primaxin) in two different total parenteral nutrient (TPN) solutions was determined. TPN solutions consisted of 4.25% and 5% amino acids with 25% and 35% dextrose, respectively. Imipenem-cilastatin sodium was constituted with 10 ml of sterile water and admixed with 90 ml of TPN solution for a final concentration of 5 mg/ml of each drug. The final solutions were assayed at times 0 (immediately after admixture), 15 min, 30 min, 1, 4, 8, and 24 hr by a stability-indicating high-performance liquid chromatographic assay. Concurrently, test TPN solutions were monitored for pH changes, color changes, and precipitate formation. The potential effect of imipenem-cilastatin sodium on the stability of amino acids and other TPN additives was not evaluated. Imipenem and cilastatin sodium was stable (greater than or equal to 90% recovered) in each TPN solution at 15 min. A significant (greater than or equal to 10%) and steady decrease of imipenem recovery occurred at subsequent sampling times. Cilastatin appeared more stable than imipenem in both TPN solutions. A physical color change from colorless to dark orange appeared in each TPN solution over the 24-hr study period. Imipenem-cilastatin sodium is stable for 15 min in the TPN solutions studied; however, until the stability of the amino acids can be determined, the antibiotic should be administered through a separate line or Y-site while the TPN infusion is interrupted.
authors.affiliation: Department of Pharmacy Services, University of Michigan, Ann Arbor.
authors.forename: D S
authors.initials: DS
authors.lastname: Zaccardelli
authors.forename: C S
authors.initials: CS
authors.lastname: Krcmarik
authors.forename: R
authors.initials: R
authors.lastname: Wolk
authors.forename: N
authors.initials: N
authors.lastname: Khalidi
mesh_terms: D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000032:analysis / Q000592:standards*; D002851:Chromatography, High Pressure Liquid; D015377:Cilastatin / Q000008:administration & dosage / Q000032:analysis / Q000592:standards*; D000077728:Cilastatin, Imipenem Drug Combination; D004338:Drug Combinations / Q000008:administration & dosage / Q000032:analysis / Q000592:standards; D004344:Drug Incompatibility; D004355:Drug Stability; D005526:Food, Formulated / Q000032:analysis; D006801:Humans; D015378:Imipenem / Q000008:administration & dosage / Q000032:analysis / Q000592:standards*; D010289:Parenteral Nutrition, Total
chemical_list: D000900:Anti-Bacterial Agents; D004338:Drug Combinations; D015377:Cilastatin; D015378:Imipenem; D000077728:Cilastatin, Imipenem Drug Combination