title: An in vitro study of the potency and stability of fortified ophthalmic antibiotic preparations.
abstract: We studied the potency of fortified ophthalmic antibiotic preparations of cefazolin sodium (50 mg/ml) and tobramycin sulfate (15 mg/ml), as measured by the minimum inhibitory concentration, against Streptococcus pneumoniae and Pseudomonas aeruginosa, respectively. We also examined absorbance spectra, pH, and the effect of storage temperature on these fortified solutions to determine their stability over a four-week period. Cefazolin and tobramycin maintained a constant potency throughout the experiment. There was no difference in potency if the fortified solutions were stored at 4 C or 24 C. Cefazolin stored at 24 C exhibited changes in both its absorbance spectra and pH after seven days. Cefazolin stored at 4 C and tobramycin stored at 24 C and 4 C remained stable throughout the four-week period.
authors.affiliation: Department of Ophthalmology and Visual Sciences, University of Louisville, Kentucky.
authors.forename: B E
authors.initials: BE
authors.lastname: Bowe
authors.forename: J W
authors.initials: JW
authors.lastname: Snyder
authors.forename: R A
authors.initials: RA
authors.lastname: Eiferman
mesh_terms: D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000494:pharmacology*; D002437:Cefazolin / Q000008:administration & dosage / Q000494:pharmacology; D004355:Drug Stability; D004356:Drug Storage; D009883:Ophthalmic Solutions; D011550:Pseudomonas aeruginosa / Q000187:drug effects; D013296:Streptococcus pneumoniae / Q000187:drug effects; D013696:Temperature; D013997:Time Factors; D014031:Tobramycin / Q000008:administration & dosage / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D009883:Ophthalmic Solutions; D002437:Cefazolin; D014031:Tobramycin