Pradofloxacin release from the OphthaCoil: a new device for sustained delivery of drugs to the eye

The release of the antibiotic pradofloxacin from a new ocular insert called the OphthaCoil was evaluated. The ocular insert consists of a drug-loaded adherent hydrogel on a thin wire, which is coiled. The inner lumen of the coil was filled with a polymer rod made from a poly(2-hydroxyethyl methacrylate) hydrogel and loaded with the same drug. The in vitro release of pradofloxacin and its pharmacokinetics in dog tear fluid was evaluated over a 72-h time interval. The results show that in vitro release is faster than in vivo release, probably because the refresh time for tear fluid in the eye is slower than in the in vitro experiments. In vivo, the drug level in the tear fluid remained within the concentration range during the entire 72 h, which is when pradofloxacin is expected to be active against the most relevant bacteria species involved in canine conjunctival infections. These results are quite promising for the future application of the OphthaCoil in veterinary or human ophthalmology.