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Sustained Dexamethasone Drug Delivery System. Ozurdex and Novadur Implant. First approved pharmacotherapy for macular edema following BRVO and CRVO. Dr. Bharti Kashyap Kashyap Memorial Eye Hospital. A biodegradable dexamethasone implant Drug incorporated into polymer matrix
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Sustained Dexamethasone Drug Delivery System Ozurdex and Novadur Implant First approved pharmacotherapy for macular edema following BRVO and CRVO Dr. Bharti Kashyap Kashyap Memorial Eye Hospital
A biodegradable dexamethasone implant • Drug incorporated into polymer matrix • Sustained medication release • Polymer matrix gradually breaks down into inert compounds • Extruded form is implanted with an applicator – the NOVADUR™ implant • Self-sealing wound
NOVADUR™implant • Rod shaped tiny implant • 0.45 mm in diameter and 6 mm in length • Contains 0.7mg of Dexamethasone (preservative free) • Novadur is a proprietary and innovative drug delivery system (DDS). • Dexamethasone embedded in an inactive biodegradable PLGA matrix. (60/40 drug/polymer)
Drug Release From Biodegradable Implants Three Phases of Release Surface Release
Drug Release From Biodegradable Implants Three Phases of Release Diffusion
Drug Release From Biodegradable Implants Three Phases of Release Bulk Erosion
Lactic Acid Glycolic Acid Drug Delivery Technology Water and Carbon Dioxide Biodegradable Implant Gradually Transforms Into Water and Carbon Dioxide
Changes in Polymer Matrix Over Time Before Implantation After 3 Weeks
Implanted with 22-gauge applicator • Through the pars plana • Wound is self-sealing • No sutures required • Implant does not need to be sutured into place
Inflammation: a key component in the pathogenesis of retinal disease1,2 Retinal vein occlusion (RVO)1 Uveitis1 Inflammation Neovascularisation Vascular leakage Retinal disease Wet age-related macular degeneration (wet AMD)2 Diabetic retinopathy (DR)/diabetic macular edema (DME)1 • Johnson MW. Am J Ophthalmol 2009;147:11–21; • Nowak JZ. Pharmacol Rep 2006;58:353–63.
Healthy Retinal Microvessel Vascular Disease • Diabetes • CRVO/ BRVO • Vasodilation • Leukostasis • Diapedesis • Permeability • Inflammatory proteins Macular Edema PathophysiologyCorticosteroid-Based Therapies Primary Inflammatory Disease • Uveitis VEGF • Inflammatory Mediator • IL-1, 6, 8 • TNF-Alpha
Corticosteroid-Based Therapies Corticosteroids inhibit the inflammatory response to a variety of inciting agents. They inhibit the edema formation, fibrin deposition, capillary dilation, leukocyte migration, capillary proliferation, deposition of collagen, and scar formation associated with inflammation. They stabilize endothelial cells tight junctions, inhibit the synthesis of VEGF, prostaglandins & other key cytokines.
Corticosteroid-Based Therapies Arachidonic acid is released from membrane phospholipids by phospholipase A2 . It is postulated that lipocortinscontrol the biosynthesis of potent mediators of inflammation such as prostaglandins and leukotrienes. Corticosteroids are thought to act by the induction of phospholipase A2 inhibitory proteins, collectively called lipocortins.
Phospholipase A2 . lipocortins Prostaglandins Leukotrienes Arachidonic acidCorticosteroids
Healthy Retinal Microvessel Vascular Disease • Diabetes • CRVO/ BRVO Corticosteroids • Vasodilation • Leukostasis • Diapedesis • Permeability • Inflammatory proteins Macular Edema PathophysiologyCorticosteroid-Based Therapies Primary Inflammatory Disease • Uveitis VEGF • Inflammatory Mediator • IL-1 • TNF-Alpha
Relative Potencies of Corticosteroids Table 59-2 Goodman & Gilman 9th Edition *approximated from the literature
Desired characteristics of an implantable intravitreal drug delivery system • Controlled, sustained drug release • Simple insertion procedure • Biodegradable implant (does not need to be removed) • Long-term safety