Stability of a 50 mg/mL Ceftazidime Eye-Drops Formulation

Microbial keratitis are severe infections generally linked to risk factors. High-doses antibiotic eye-drops could be required to avoid severe complications. In such cases, hospital pharmacists are in charge of their production given the lack of such formulations on the market. The stability of these antibiotic eye-drops is generally limited to a couple of days and publications generally do not describe addition of microbial preservatives even though it is a European Pharmacopeia requirement. The aim of this study was to describe a new ceftazidime eye-drops formulation at 50 mg/mL with a antimicrobial additive, benzalkonium chloride at 0.04 mg/mL. Physico-chemical studies of this new formulation were performed by a stability indicating HPLC-UV method validated according to ICH standards, osmolality measurements, pH monitoring and visual examinations. Antimicrobial preservative efficacy was evaluated according to the method from the European Pharmacopeia. After 75 days at −20 °C followed by 7 days at 4 °C, or after 7 days at 4 °C, the eye-drops were stable. A degradation trend was finally observed at day 14 at 4 °C A new ceftazidime eye-drops formulation is proposed with a stability of 7 days. Outpatients do not need to return to the hospital pharmacy for repeat dispensing, thus possibly improving treatment compliance.