title: Stability of gentamicin sulfate and tobramycin sulfate in extemporaneously prepared ophthalmic solutions at 8 degrees C.
abstract: The stability of gentamicin sulfate and tobramycin sulfate in fortified ophthalmic solutions stored under refrigeration was studied. Fortified gentamicin ophthalmic solution and fortified tobramycin ophthalmic solution were prepared to a final theoretical concentration of 13.6 mg/mL by using commercially available ophthalmic and injectable solutions. Volumes of each solution were packaged in plastic bottles and refrigerated at 4-8 degrees C. Samples of each solution were analyzed by fluorescence polarization immunoassay on days 0 (before refrigeration), 1, 2, 3, 4, 7, 14, 28, 63, and 91. To validate the method, identical solutions were prepared, stored under refrigeration at 4-8 degrees C, and analyzed by a stability-indicating high-performance liquid chromatographic assay on days 0 (before refrigeration), 9, 28, 56, and 91. Fluorescence polarization immunoassay showed the mean concentrations of gentamicin and tobramycin on day 91 to be 104.4% and 97.4%, respectively, of the time 0 concentrations; the difference was not significant in either case. HPLC validated these results; the mean concentration of gentamicin and tobramycin on day 91 was 103.3% and 101.2%, respectively, of the mean day 0 concentrations. Gentamicin and tobramycin in ophthalmic solutions prepared by mixing ophthalmic and injectable products and stored in plastic bottles at 4-8 degrees C were stable for three months.
authors.affiliation: School of Pharmacy, Samford University, Birmingham, AL 35229.
authors.forename: H A
authors.initials: HA
authors.lastname: McBride
authors.forename: D R
authors.initials: DR
authors.lastname: Martinez
authors.forename: J M
authors.initials: JM
authors.lastname: Trang
authors.forename: R D
authors.initials: RD
authors.lastname: Lander
authors.forename: H A
authors.initials: HA
authors.lastname: Helms
mesh_terms: D002851:Chromatography, High Pressure Liquid; D003080:Cold Temperature; D004355:Drug Stability; D005839:Gentamicins / Q000737:chemistry*; D006801:Humans; D009883:Ophthalmic Solutions / Q000737:chemistry; D014031:Tobramycin / Q000737:chemistry*
chemical_list: D005839:Gentamicins; D009883:Ophthalmic Solutions; D014031:Tobramycin