Frozen fortified antibiotic in ophthalmic solutions stability during 2 months

Abstract

Purpose: Fortified antibiotic ophthalmic solutions are regularly administered as an immediate treatment for bacterial keratitis. The fortified antibiotics were used to be self‐prepared by nurses. To solve this problem, pharmacy staff studied the stability of three 5% solutions of vancomycin, amikacin and ceftazidim, prepared in aseptic conditions from parenteral antibiotic solutions. Methods: Solutions were frozen at ‐20°C. Portions of each solution were examined before storage and over a 75‐days period. Ceftazidim and amikacin were dilute in 0,9% sodium chloride and vancomycin in 5% dextrose. Over a 75 days period, physical, pharmacological (absorbance spectra) properties and sterility of each stock solution were studied. Results: The pH of amikacin (6,51), ceftazidim (6,47) and vancomycin (3,77) remained stable during the 75 days period. Osmolarities also remained stable (367, 488 and 351 mOsm/L). There were no significant differences in the concentration, osmolarity and pH of the three antibiotic solutions before storage and after 75 days of freezing. Over a 75 days period, stability of amikacin, ceftazidim and vancomycin remained constant; no contamination was detected before storage and after 75 days. Conclusions: Topical fortified antibiotic solutions can be stored 75 days at ‐20°C (15 days quarantine). After, these eye‐drops should be stored at 4°C and should be discarded after 3 days.