[Intravitreally injectable poly (D, L-Lactide) microspheres containing dexamethasone acetate for sustained release]

Area of Science:

• Ophthalmology
• Biomaterials Science
• Drug Delivery Systems

Background:

• Proliferative vitreoretinopathy (PVR) is a serious complication of retinal detachment, leading to vision loss.
• Current treatments for PVR often involve repeated interventions and may have limited efficacy.
• Sustained drug delivery systems are needed to improve therapeutic outcomes for PVR.

Purpose of the Study:

• To develop and characterize dexamethasone acetate-loaded poly (d, l-lactide) microspheres.
• To evaluate the in vitro sustained release profile of dexamethasone acetate from these microspheres.
• To assess the in vivo therapeutic efficacy of the microspheres in an experimental model of PVR.

Main Methods:

• Microspheres were prepared using a solvent evaporation/extraction technique.
• Characterization included particle size, drug loading, entrapment efficiency, and in vitro release studies.
• Physical state of dexamethasone acetate within the microspheres was analyzed using DSC and XRD.
• In vivo safety and therapeutic effects were evaluated in a rabbit model of PVR.

Main Results:

• Microspheres exhibited a geometric mean diameter of 62.9 microns and a span of 0.92.
• Drug loading was 17.5% with an entrapment rate of 86.5%.
• In vitro release showed 90% drug release over 90 days, significantly longer than free drug release.
• In vivo studies demonstrated sustained dexamethasone acetate release for 84 days and significant suppression of PVR compared to control groups.

Conclusions:

• Poly (d, l-lactide) microspheres provide a promising platform for sustained delivery of dexamethasone acetate.
• This system effectively suppressed experimental proliferative vitreoretinopathy in vivo.
• Dexamethasone acetate-loaded microspheres represent a potentially valuable therapeutic strategy for managing PVR.