Evaluation of Levofloxacin Release Characteristics from a Human Foldable Capsular Vitreous Body In Vitro

Purpose: We have manufactured a novel human foldable capsular vitreous body (FCVB). In this article, we determine whether the human FCVB releases levofloxacin in vitro and evaluate the release characteristics. Methods: Levofloxacin at dosages of 100, 250, and 500 mu g/mL in 4.0 mL H2O was injected into the novel human FCVB; then, the capsules were immersed in cups of modified Franz diffusion cells. Two hundred microliters of liquid was aspirated at intervals of 10, 20, 40, 60, 120, 180, 240, 300, and 360 min. The levofloxacin concentrations in the cups were detected using the liquid chromatographic-tandem mass spectrometry (HPLC-MS/MS) method. Five hundred mu g/mL levofloxacin liquor at volumes of 4.0, 5.0, and 6.0 mL was injected into the novel human FCVB, and the release characteristics were detected for each. The capsules of the FCVB were observed under scanning electron microscopy before and after the release study. Results: The novel human FCVB released levofloxacin in a time-dependent manner under 100, 250, and 500 mu g/mL dosages from 10 to 360 min. Particularly in the 250 mu g/mL levofloxacin group, the concentration (Q) had a good linear relationship with time (t(1/2)), Q=1.3381t(1/2) + 10.2818 (r = 0.9954, Higuchi equation). The human FCVB released levofloxacin in a dose-dependent manner under 100, 250, and 500 mu g/mL dosages from 10 to 360 min in the total tendency, but the 500 mu g/mL group released less levofloxacin than the 250 group at 300 and 360 min. The human FCVB did not release levofloxacin in a volume-dependent manner with 4.0, 5.0, and 6.0 mL volume. The 4.0-mL volume group released more levofloxacin than the other 2 volume groups. Numerous 300-nm-mili apertures were observed in the capsule of the FCVB at the beginning and end of this observation. Conclusions: A human FCVB can sustainably, in vitro, mechanically release levofloxacin in both a time-dependent and dose-dependent manner, but not in a volume-dependent manner. This study sets forth a novel combined research and therapeutic strategy as a vitreous substitute and intravitreal drug delivery system for the treatment of bacterial endophthalmitis.