Precipitation of Vancomycin and Ceftazidime on Intravitreal Injection in Endophthalmitis Patients

Clinical Characteristics, Pathogen Distribution, and Factors Affecting Visual Outcomes of Pediatric Post-Traumatic Endophthalmitis

Objective: This study aimed to investigate the etiology, pathogens, antibiotic susceptibility, treatments, and factors influencing the visual prognosis of pediatric post-traumatic endophthalmitis (PTE) to provide valuable insights for clinical diagnosis and treatment. Results: A total of 301 children were included, with 142 (47.2%) cultures yielding positive results. Gram-positive cocci were the predominant pathogens (71.1%), with high sensitivity to vancomycin (95.4%). Pars plana vitrectomy (PPV) was performed in 216 eyes (71.8%), with emergency or immediate vitrectomy within 24 h of hospitalization performed on 171 eyes (56.8%). The first intravitreal antibiotic injection, consisting of ceftazidime and norvancomycin, was administered to 248 patients (82.4%). The absence of retinal detachment (OR, 0.191; 95% CI, 0.065-0.560; p = 0.002), normal intraocular pressure (OR, 1.894; 95% CI, 1.151-3.117; p = 0.012), and no lens extraction (OR, 0.187; 95% CI, 0.069-0.504; p < 0.001) were found to be independent factors associated with better visual outcomes (BCVA) in pediatric PTE patients. Methods: A retrospective analysis was conducted on pediatric PTE patients treated between January 2012 and June 2022. Data were collected on clinical characteristics, causative pathogens, antibiotic sensitivity, treatments, and visual outcomes. Conclusions: Gram-positive cocci are the most common pathogens in pediatric PTE, with early vitrectomy and intravitreal ceftazidime and norvancomycin being the most effective treatments. Favorable visual outcomes are strongly associated with the absence of retinal detachment, normal intraocular pressure, and no lens extraction. These findings highlight the need for timely surgical and antimicrobial interventions tailored to each patient to improve visual prognosis.

Cyclodextrins Allow the Combination of Incompatible Vancomycin and Ceftazidime into an Ophthalmic Formulation for the Treatment of Bacterial Keratitis

Ceftazidime (CZ) and vancomycin (VA) are two antibiotics used to treat bacterial keratitis. Due to their physical incompatibility (formation of a precipitate), it is not currently possible to associate both molecules in a single container for ophthalmic administration. We firstly characterized the incompatibility then investigated if 2-hydroxypropyl-beta (HPβCD) and 2-hydroxypropyl-gamma cyclodextrins (HPγCD) could prevent this incompatibility. The impact of pH on the precipitation phenomena was investigated by analysing the supernatant solution of the mixture using high performance liquid chromatography. A characterization of the inclusion of CZ with HPγCD using ¹H nuclear magnetic resonance (NMR), and VA with HPβCD using ¹H-NMR and a solubility diagram was performed. A design of experiment was built to determine the optimal conditions to obtain a formulation that had the lowest turbidity and particle count. Our results showed that VA and CZ form an equimolar precipitate below pH 7.3. The best formulation obtained underwent an in-vitro evaluation of its antibacterial activity. The impact of HPCDs on incompatibility has been demonstrated through the inclusion of antibiotics and especially VA. The formulation has been shown to be able to inhibit the incompatibility for pH higher than 7.3 and to possess unaltered antibacterial activity.