Background The treatment of endophthalmitis is usually instillation of fortified antibiotic eye drops and/or intraocular injections of ceftazidime and vancomycin. Hospital pharmacies have to make these ophthalmic preparations to mitigate the lack of commercially-available medicines and store them to manage urgent requests. Numerous studies have been carried out to determine the stability of these preparations.

Purpose A literature review of studies concerning the stability of eye drops and prepared intraocular injections of ceftazidime and vancomycin.

Materials and methods Research was based on references such as Trissel's stability of compounded formulations, Handbook on injectable drugs, or databases such as Scopus. Various criteria were listed depending on the study: the concentration of the solution, the solvent, the conditions of storage and the duration of stability. Studies are classified in summary tables, one for each drug.

Results 18 studies were found for ceftazidime and 22 studies for vancomycin. Two studies stand out and the formulations they recommend seem to be most suitable for long term storage. The first one concluded that 6 months' stability for syringes for intraocular injection of vancomycin at 10 mg/mL and for ceftazidime at 22.5 mg/mL could be obtained by freezing at -18 °C. The second one settled on a stability of 75 days for vancomycin eye drops at 50 mg/ml in glucose 5% and for 50 mg/ml ceftazidime in sodium chloride 0.9% by freezing at -20°C.

Conclusions Freezing enables standardised hospital preparations to be stored for long periods, which makes it possible to build up a useful stock and as a result to resolve the problem of urgent care. Thanks to this review the pharmacists can choose the best option, in consultation with the medical teams (in particular for the choice of the solvent) and respond to situations in which urgent treatment is required.