Stability of 5% vancomycin ophthalmic solution prepared using balanced salt solution after freezing for 90 days.

PURPOSE: To evaluate the stability of 5% vancomycin ophthalmic solution prepared using balanced salt solution (BSS) and stored at -20°C in polypropylene containers. METHODS: Six batches of vancomycin 50 mg/mL eyedrops were aseptically prepared. One bottle of each batch was analyzed immediately after preparation, and the rest were stored at -20°C and analyzed using high-performance liquid chromatography (HPLC) at 30, 60, and 90 days to test their physicochemical stability and sterility. Thereafter, bottles were removed from the freezer and stored at 5°C for 30 days, with HPLC and other analyses repeated 105 and 120 days after preparation. All samples were analyzed in triplicate. Stability was defined as the absence of particles, color variation, or changes in pH and a remaining vancomycin concentration of 90% to 110% of the initial concentration. The sterility of the ophthalmic solution was evaluated by using soybean-casein digest broth with resins; samples were incubated for 7 days and checked daily for signs of microbial growth. RESULTS: There was no particle formation or sign of precipitation in any of the solutions throughout the duration of the study, regardless of the storage conditions. No change in color or turbidity was observed. The pH and osmolarity remained unchanged during storage at -20°C and after thawing. The vancomycin concentration remained within 10% of the initial concentration during the 90-day period of storage at -20°C and the subsequent 30 days after thawing. Sterility was preserved in all samples. CONCLUSION: A 5% solution of vancomycin prepared using BSS was physicochemically and microbiologically stable when stored at -20°C for 90 days. After thawing, this extemporaneous formulation remained stable when refrigerated at 5°C for 30 days.

Stability of frozen 1% voriconazole ophthalmic solution.

PURPOSE: The physicochemical stability of frozen 1% voriconazole ophthalmic solution was evaluated. METHODS: Multiple batches of voriconazole 10-mg/mL eye drops were aseptically prepared in a laminar-airflow cabinet. One batch was analyzed immediately after preparation, and the rest were stored at -20 °C and analyzed using high-performance liquid chromatography at 30, 60, and 90 days to test their physicochemical stability and sterility. All samples were analyzed in triplicate. Additional analyses were performed to determine the solution's in vitro activity once thawed. The sterility of the 1% voriconazole solution was evaluated using blood-agar media and thioglycollate broth. Samples were incubated for 14 days and checked daily for signs of growth. Stability was defined as the absence of particles, color variation, or changes in pH and a remaining antifungal concentration of 90-110% of the initial concentration. RESULTS: All solutions remained clear and colorless throughout the study, and no precipitation or turbidity was observed in any of the batches, regardless of solution temperature. The pH and osmolarity of all batches remained essentially unchanged during storage at -20 °C and after thawing. No significant differences in concentration were observed during the storage at -20 or 5 °C. The voriconazole concentration remained within 10% of the initial concentration during the 90-day period of storage at -20 °C. The percentage of recovery was also optimal after thawing. CONCLUSION: Voriconazole 1% solution prepared for ophthalmic use was stable and retained antifungal activity when stored at -20 °C for 90 days. After thawing, this extemporaneously prepared formulation was stable at 5 °C for 14 days.