Dexamethasone implant improves anatomic response to anti-VEGF therapy in treatment-resistant polypoidal choroidal vasculopathy

Design of liposomal nanocarriers with a potential for combined dexamethasone and bevacizumab delivery to the eye

Clinicians face numerous challenges when delivering medications to the eyes topically because of physiological barriers, that can inhibit the complete dose from getting to the intended location. Due to their small size, the ability to deliver drugs of different polarities simultaneously, and their biocompatibility, liposomes hold great promise for ocular drug delivery. This study aimed to develop and characterise a dual loaded liposome formulation encapsulating Bevacizumab (BEV) and Dexamethasone (DEX) that possessed the physicochemical attributes suitable for topical ocular delivery. Liposomes were prepared by using thin film hydration followed by extrusion, and the formulations were optimised using a design of experiments approach. Physicochemical characterisation along with cytocompatibility and bioactivity of the formulations were assessed. Liposomes were successfully prepared with a particle size of 139 ± 2 nm, PDI 0.03 ± 0.01 and zeta potential -2 ± 0.7 mV for the optimised formulation. BEV and DEX were successfully encapsulated into the liposomes with an encapsulation efficiency of 97 ± 0.5 % and 26 ± 0.5 %, respectively. A sustained release of BEV was observed from the liposomes and the bioactivity of the formulation was confirmed using a wound healing assay. In summary, a potential topical eye drop drug delivery system, which can co-load DEX and BEV was developed and characterised for its potential to be used in ocular drug delivery.

Dexamethasone Intravitreal Implant for the Treatment of Macular Edema and Uveitis: A Comprehensive Narrative Review

Purpose

The purpose of this review article is to provide a comprehensive review of the current applications of intravitreal DEX implant (Ozurdex^®, Allergan Inc, Irvine, CA) for a variety of ophthalmic conditions – ranging from FDA approved indications to off-label uses. We have attempted to provide relevant evidence from the literature to help a reader develop an understanding of the biological and pharmacokinetic properties of DEX implant, its uses, and potential side effects.

Methods

PubMed searches were performed using the terms “Ozurdex”, or “intravitreal DEX implant”, AND “retinal vein occlusion”, or “diabetic macular edema”, or “uveitis”. The search was performed in July of 2021, with an additional search in October 2021. All original English language articles were considered for this review.

Results

DEX implant has evidence of efficacy in a variety of clinical situations including macular edema associated with retinal vein occlusion, diabetes, uveitis, and others. Safety concerns include cataract formation and progression, intraocular pressure elevation, complications related to intravitreal injection, and opportunistic infections secondary to steroid-induced immune suppression.

Conclusion

DEX implant is a useful tool in the management of several retinal disorders. Further studies are needed for head-to-head comparison with other treatment modalities and to determine its precise place in clinical practice.