Dexamethasone Implant Pharmacokinetics in Rabbit Eyes: A Comparative Study

A recent study conducted on rabbits has revealed comparable ocular pharmacokinetic profiles between Ozurdex®, a currently marketed dexamethasone implant, and NDF-SI01, a newer potential generic alternative. The research, detailed in publications including the Journal of Ocular Pharmacology and Therapeutics, focused on determining how each implant releases dexamethasone into the vitreous humor of the eye over time.

Dexamethasone implants are utilized in the treatment of macular edema and non-infectious uveitis, inflammatory conditions affecting the eye. As the patent for Ozurdex® nears expiration, the development of generic versions, such as NDF-SI01, has gained momentum. The study aimed to characterize the ocular pharmacokinetics of these implants to support the potential clinical adoption of alternatives.

Researchers implanted both Ozurdex® and NDF-SI01 into the eyes of rabbits, then serially collected vitreous samples to measure dexamethasone concentrations. Analysis using HP LC-MS/MS revealed that dexamethasone concentration peaked at 3.1 μg/mL approximately 19.5 days post-implantation, with a half-life of 40.3 hours. The area under the curve (AUC) was 683.9 μg·h/mL, and the clearance rate was 1.29 mL/h.

Crucially, the study found no statistically significant differences in pharmacokinetic parameters between NDF-SI01 and Ozurdex®. The cumulative release patterns of both implants were also found to be similar. Both implants contain 0.7 mg of dexamethasone combined with biodegradable polymers, specifically polylactide-co-glycolide (PLGA).

The findings suggest that NDF-SI01 could potentially serve as an alternative to Ozurdex® in clinical practice, based on the in vivo pharmacokinetic data and in vitro dissolution testing. Further studies will be needed to confirm these findings and assess long-term safety and efficacy in human patients.