Abstract
Purpose :
Prophylaxis of endophthalmitis after cataract surgery currently includes the administration of topical and intra-camerular antibiotics. An alternative could be the implantation of drug-loaded intraocular lenses (IOLs) with the ability to deliver a controlled amount of antibiotic during an adequate period of time. Despite IOLs sterilization is mandatory to fulfil strict microbiological safety requirements, it must not compromise the biomaterial properties. The goal of our study was to investigate the effect of two sterilization methods (steam autoclaving and g-irradiation) on moxifloxacin antimicrobial activity, IOLs biomaterial properties and moxifloxacin-loaded IOLs drug release profiles.
Methods :
A solution of moxifloxacin (2 mg/mL in NaCl 0,9%), commercial IOLs provided by PhysIOL and drug-loaded IOLs (soaked in a moxifloxacin solution 2 mg/mL) were sterilized by steam and pressure (60 min, 121 C, 1 bar) and γ-radiation (doses 5, 15 and 25 kGy). The drug-loaded IOLs were sterilized in the same solution as the loading solution. The activity of the drug was studied by high performance liquid chromatography (HPLC) and microbiological tests. IOLs biomaterial properties, as transparency (UV-Vis spectroscopy), wettability (captive bubble method) and swelling behavior were characterized. Drug release experiments were carried out at 36 C in sink conditions (3 mL NaCl solution/lens). The quantification of the released drug was done by HPLC.
Results :
Results of both HPLC and microbiological tests showed that steam sterilization did not induce drug degradation. The γ-radiation led to different results depending on the doses: while 5 kGy did not lead to significant changes on drug activity, 15 and 25 kGy led to a high level of degradation. So the latter were abandoned. Concerning biomaterial properties, steam sterilization and γ-radiation at 5 kGy did not affect transmittance and swelling behaviour, but slightly increased wettability.
Contrarily to γ-radiation, steam sterilization induced strong changes in the drug release profile, being released a higher amount of drug than from non-sterilized samples and with a more sustained kinetics.
Conclusions :
The sterilization conditions may be critical for drug-loaded IOLs. In our study, steam sterilization revealed to be the best sterilization method, since it did not affect the antibiotic activity and significantly improved the drug release profiles.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.