Intravitreal triamcinolone for intraocular inflammation and associated macular edema

In vivo evaluation of a Nano-enabled therapeutic vitreous substitute for the precise delivery of triamcinolone to the posterior segment of the eye

This study focused on the design of a thermoresponsive, nano-enabled vitreous substitute for the treatment of retinal diseases. Synthesis of a hydrogel composed of hyaluronic acid and a poloxamer blend was undertaken. Poly(D,L-lactide-co-glycolide) acid nanoparticles encapsulating triamcinolone acetonide (TA) were synthesised with a spherical morphology and mean diameter of ~ 153 nm. Hydrogel fabrication and nanoparticle loading within the hydrogel was confirmed via physicochemical analysis. Gelation studies indicated that hydrogels formed in nine minutes and 10 min for the unloaded and nanoparticle-loaded hydrogels, respectively. The hydrogels displayed in situ gel formation properties, and rheometric viscoelastic studies indicated the unloaded and loaded hydrogels to have modulus values similar to those of the natural vitreous at 37 °C. Administration of the hydrogels was possible via 26G needles allowing for clinical application and drug release of triamcinolone acetonide from the nanoparticle-loaded hydrogel, which provided sustained in vitro drug release over nine weeks. The hydrogels displayed minimal swelling, reaching equilibrium swelling within 12 h for the unloaded hydrogel, and eight hours for the nanoparticle-loaded hydrogel. Biodegradation in simulated vitreous humour with lysozyme showed < 20% degradation within nine weeks. Biocompatibility of both unloaded and loaded hydrogels was shown with mouse fibroblast and human retinal pigment epithelium cell lines. Lastly, a pilot in vivo study in a New Zealand White rabbit model displayed minimal toxicity with precise, localised drug release behaviour, and ocular TA levels maintained within the therapeutic window for the 28-day investigation period, which supports the potential applicability of the unloaded and nanoparticle-loaded hydrogels as vitreous substitutes that function as drug delivery systems following vitrectomy surgery.

Risk factors for failing sub-Tenon's triamcinolone acetonide for uveitic macular edema

BACKGROUND

Sub-Tenon's triamcinolone acetonide (STA) is less effective than intravitreal corticosteroids in the treatment of uveitic macular edema (ME), but does have some relative advantages, including substantially lower cost and decreased risk of post-injection ocular hypertension. It would be useful for clinicians to know which eyes may respond well to STA and not necessarily require intravitreal therapy. The objective of this study is to identify risk factors for failing STA for the treatment of uveitic ME.

MAIN BODY

A retrospective cohort study was performed. Medical records were reviewed of patients who underwent STA for the treatment of uveitic ME between January 1, 2013, and July 31, 2022, at the University of Colorado Hospital. Uveitic ME was defined by a central subfield thickness (CST) greater than 320 μm or the presence of intra-retinal cystoid spaces on optical coherence tomography (OCT), or by the presence of petaloid macular leakage on fluorescein angiography (FA). Data collected included age, race/ethnicity, sex, history of diabetes mellitus, anatomic classification of uveitis, use of corticosteroids, use of immunomodulatory therapy, presence of intra-retinal fluid on OCT, CST on OCT, and presence of petaloid macular leakage on FA. STA failure was defined as the need for additional therapy within 12 weeks of STA due to persistent or worsening uveitic ME. One hundred eighty eyes from 131 patients were included. Forty-two eyes (23.3%) were considered treatment failures. In univariate and multivariable analysis, higher baseline CST was associated with a higher likelihood of failing STA (OR 1.17 for each 30 μm increase in CST, P = 0.016).

CONCLUSIONS

STA, while not as potent as intravitreal corticosteroids for the treatment of uveitic ME, was still an effective therapy, particularly for patients with lower baseline CST. Given its lower side effect profile and cost compared to intravitreal treatments, clinicians could consider STA as an initial treatment for mild uveitic ME.

Fabrication and Characterisation of 3D-Printed Triamcinolone Acetonide-Loaded Polycaprolactone-Based Ocular Implants

Triamcinolone acetonide (TA) is a corticosteroid that has been used to treat posterior segment eye diseases. TA is injected intravitreally in the management of neovascular disorders; however, frequent intravitreal injections result in many potential side effects and poor patient compliance. In this work, a 3D bioprinter was used to prepare polycaprolactone (PCL) implants loaded with TA. Implants were manufactured with different shapes (filament-, rectangular-, and circle-shaped) and drug loadings (5, 10, and 20%). The characterisation results showed that TA was successfully mixed and incorporated within the PCL matrix without using solvents, and drug content reached almost 100% for all formulations. The drug release data demonstrate that the filament-shaped implants (SA/V ratio~7.3) showed the highest cumulative drug release amongst all implant shapes over 180 days, followed by rectangular- (SA/V ratio~3.7) and circle-shaped implants (SA/V ratio~2.80). Most implant drug release data best fit the Korsmeyer−Peppas model, indicating that diffusion was the prominent release mechanism. Additionally, a biocompatibility study was performed; the results showed >90% cell viability, thus proving that the TA-loaded PCL implants were safe for ocular application.

Local versus Systemic Therapy for Noninfectious Uveitis (NIU)

The mainstay of treatment for noninfectious uveitis (NIU) is immunosuppressant therapy. This may come in a localized form that is administered specifically to the eye or a systemic form that penetrates ocular tissues. Over the last twenty years, both local and systemic treatments have undergone advancements in pharmaceutical development. In this review, we will discuss new therapies and analyze the risks and benefits for all existing NIU therapies. Some of these therapies include topical, intravitreal, periocular, and systemic steroids, as well as systemic antimetabolites, tumor necrosis factor-α inhibitors, T-cell inhibitors, anti-CD 20 agents, interleukin-6 inhibitors, alkylating agents, and intravenous immunoglobulin.

Preventive factors, diagnosis, and management of injection-related endophthalmitis: a literature review

BACKGROUND

Intravitreal medication injections represent the gold standard treatment for a variety of potentially blinding chorioretinal vascular diseases. Despite their excellent safety profile, they are associated with the feared complication of injection-related endophthalmitis (IRE). Though the overall incidence of IRE is low, due to the ever-increasing number of injections being performed, it is a complication that all retina specialists are likely to encounter. This article reviews various factors that could potentially influence the risk of IRE and discusses evidence-based strategies for management.

METHOD

PubMed was searched for keywords "intravitreal injection" and "endophthalmitis" from the period of 1995-2021. Relevant articles were reviewed and selected articles were analyzed with respect to the incidence, potential preventive factors, clinical presentation, microbial profile, management, and outcomes for IRE.

RESULTS

There is strong consensus supporting the use of povidone iodine topical antiseptic, eyelid retraction away from the injection site, and avoiding treatment of eyes with active surface or eyelid disease, but there is less agreement on the use of face masks versus "no-talking" policies and optimal anesthetic technique. Current evidence comparing tap and inject or early vitrectomy for treatment of IRE is inadequate to determine an optimal treatment strategy.

CONCLUSION

Intravitreal injections are sight saving, but even using established prophylactic measures there remains a small but real risk of infectious injection-related complications. Further investigations comparing tap and inject versus vitrectomy may help to establish optimal treatment, although the rarity of IRE makes designing adequately powered prospective trials a difficult task.

The Trend of Drug Therapy on Uveitic Macular Edema: A Bibliometric Analysis of the 100 Most Cited Articles

Background

Macular edema is the most common cause of impaired vision due to uveitis. Although various medications are available, not all uveitis patients with macular edema are satisfied with the treatment results. Therefore, solving this gap becomes the utmost concern worldwide. This study attempted to use bibliometric analysis to compare the valuable information in the top 100 highly cited studies in the field of drug therapy for uveitic macular edema (UME) and then determine the research hot spots and trends in this field.

Methods

In this study, the Science Citation Index Expanded (SCIE) of Web of Science (WOS) was used to collect the top 100 most cited studies on UME and analyze the literature from different countries/regions, institutions, and journals. The visualization knowledge maps is generated by VOSviewer and Citespace software.

Results

The top 100 highly cited studies are from 34 countries/regions. The United States has the largest number of publications, followed by the England, Spain and Germany. The top three institutions publishing highly cited literature are all from the England: University of London, University College London, and Moorfields Eye Hospital NHS Foundation Trust. Ophthalmology is the most widely published journal with 14 papers. The total number of citations is 1,371, meaning that Ophthalmology is the most authoritative journal in the field of UME drug therapy. The top two articles with the most cited times are from the United States, accounting for 36.5% of the total cited times of the top 10 articles. Keywords were divided into three clusters: the corticosteroid administration pathway, biological agents, and clinical trials. Uveitis, cystoid macular edema, efficacy, dexamethasone, and triamcinolone acetonide appeared more frequently in keywords. Researches on local and long-acting drug has gradually becoming the hot spots and trends.

Conclusion

This study concludes that bibliometric analysis can intuitively and quickly obtain the frontiers and hot spots of research in the field of UME drug therapy. Corticosteroid administration, biological agents, and clinical trials are considered the potential focus of future research.

Efficacy of intravitreal dexamethasone implant in patients with Vogt-Koyanagi-Harada Disease and bilateral panuveitis: Two case reports

INTRODUCTION

Vogt-Koyanagi-Harada (VKH) disease is a multisystemic disorder characterized by intraocular inflammation associated with serous retinal detachment, optic disc edema, uveitis, and vitritis, and is often associated with neurologic and cutaneous manifestations. Diagnosis can be assisted by fluorescein angiography and optical coherence tomography that can help evaluate changes in the retina. Therapy relies mainly on the use of corticosteroids, administrated through oral or intravenous high-dose pulses, and immunosuppressants. The purpose of our study was to assess the outcome of VKH disease with bilateral panuveitis treated with dexamethasone intravitreal implant.

PATIENT CONCERNS

Two patients without underlying disease had severe vision deterioration, eye pain, following flu-like symptoms.

DIAGNOSIS

At initial diagnosis, macular edema and sub-retinal fluid lobulated accumulation were noted under SD-OCT exam. FAG revealed multiple pinpoint leakage around macula and pooling of dye within sub-retinal space.

INTERVENTIONS

All two patients received intravenous pulse methylprednisolone at the diagnosis, followed by oral prednisolone and cyclosporine. One patient received bilateral eye dexamethasone intravitreal implant two weeks after diagnosis, while the other received left eye dexamethasone intravitreal implant at the time of diagnosis.

OUTCOMES

Vision and macular structure recovered more rapidly after receiving dexamethasone implants in the short-term follow-up. All macular structures recovered to normal, and vision recovered to 20/20 in both eyes. One patient, receiving bilateral dexamethasone implant, didn't relapse during the 13-month follow-up; the other, receiving left eye dexamethasone implant, didn't relapse during the 6-month follow-up. None of them required intravenous high-dose steroids again.

CONCLUSION

VKH disease is a multisystemic disorder; intravenous pulse steroid therapy and oral prednisolone can control systemic inflammation. In addition to systemic prednisolone treatment of VKH disease in the acute phase, dexamethasone implants can enhance short-term and long-term control of intraocular anti-inflammation.

Polymeric micelles for the ocular delivery of triamcinolone acetonide: preparation and in vivo evaluation in a rabbit ocular inflammatory model

The aim of this study was to prepare triamcinolone acetonide (TA)-loaded poly(ethylene glycol)-block-poly(ε-caprolactone) (PEG-b-PCL) and poly(ethylene glycol)-block-poly(lactic acid) (PEG-b-PLA) micelles as a potential treatment of ocular inflammation. The micelles were evaluated for particle size, drug loading capacity and drug release kinetics. Selected micellar formulations were dispersed into chitosan hydrogel and their anti-inflammatory properties were tested in rabbits using a carrageenan-induced ocular inflammatory model. Particle size ranged from 59.44 ± 0.15 to 64.26 ± 0.55 nm for PEG-b-PCL and from 136.10 ± 1.57 to 176.80 ± 2.25 nm for PEG-b-PLA micelles, respectively. The drug loading capacity was in the range of 6–12% and 15–25% for PEG-b-PCL and PEG-b-PLA micelles, respectively and was dependent on the drug/polymer weight ratio. TA aqueous solubility was increased by 5- and 10-fold after loading into PEG-b-PCL and PEG-b-PLA micelles at a polymer concentration as low as 0.5 mg/mL, respectively. PEG-b-PLA micelles suspended in chitosan hydrogel were able to sustain the drug release where only 42.8 ± 1.6% drug was released in one week. TA/PEG-b-PLA micelles suspended in chitosan hydrogel had better anti-inflammatory effects compared with the plain drug hydrogel or the drug micellar solution. Complete disappearance of the corneal inflammatory changes was observed for the micellar hydrogel. These results confirm the potential of PEG-b-PLA micelles suspended in chitosan hydrogel to enhance the anti-inflammatory properties of triamcinolone acetonide.

Topical instillation of triamcinolone acetonide-loaded emulsomes for posterior ocular delivery: statistical optimization and in vitro-in vivo studies

The objective of the present investigation was to formulate and characterize a novel lipid-based carrier-emulsomes loaded with triamcinolone acetonide (TA)/Nile red (NR) for non-invasive delivery to the posterior segment of the eye upon topical application. To optimize and delineate the effect of independent variables on dependent variables, Box-Behnken design (BBD) was adopted. The optimized batch was characterized for size, zeta potential, surface morphology by transmission electron microscopy, drug-excipient interaction by differential scanning calorimetry, osmolarity, pH, ex vivo transcorneal permeation, and stability studies. A short-term exposure (STE) test was performed on Statens Seruminstitut Rabbit Corneal (SIRC) cell lines to evaluate the in vitro ocular irritation. Precorneal retention study was performed in rabbit eyes. Confocal microscopy was used for ocular distribution studies in mice eye by preparing dye (Nile red)-loaded formulations. The surface response and contour plots along with ANOVA results demonstrated an interaction between the factors. The optimized batch had particle size of 131.17 ± 3.17 nm and entrapment efficiency of 71.56 ± 4.19%. TEM image showed unimodal, nano-sized emulsomes. TA-loaded emulsomes exhibited higher transcorneal permeation as compared to drug solution. In vitro irritation studies confirmed the safety of excipients for ophthalmic use. Fluorescence microscopic images obtained after ocular distribution studies showed strong fluorescence in inner and outer plexiform layers of the retina in comparison to dye solution confirming the delivery of dye to the posterior segment of mice eye after topical ocular instillation. Graphical abstract.

Incidence of Endophthalmitis after Intravitreal Injections: Risk Factors, Microbiology Profile, and Clinical Outcomes

PURPOSE

To report the incidence and characteristics of endophthalmitis after intravitreal injections (IVI) of antivascular endothelial growth factor agents and triamcinolone acetonide.

METHODS

Patients' medical records were retrospectively reviewed from January 2009 to June 2016, and the incidence, risk factors, clinical and microbiological characteristics of post-IVI endophthalmitis were evaluated.

RESULTS

The total number of intravitreal injections given, which included ranibizumab, bevacizumab, and triamcinolone acetonide, was 20,566, of which 27 cases developed endophthalmitis, giving an overall incidence of 0.131%. Significant reduction (p < 0.003) in incidence of endophthalmitis was observed in patients who received prefilled compounded bevacizumab injections (0.050%) compared to multiple bevacizumab injections from a single vial (0.235%). In the triamcinolone acetonide group, the incidence was 0.26%. Staphylococcus species were isolated from 18 cases (67%), and all strains were sensitive to vancomycin.

CONCLUSIONS

Adherence to strict aseptic protocols and use of prefilled compounded bevacizumab injections reduces the rate of post-IVI endophthalmitis.

Intravitreal drug administration for treatment of noninfectious uveitis

Intravitreal treatment became popular with the discovery of the blood ocular barriers, which significantly limit drug penetration in systemic or topical administration. As the mainstay of treatment in noninfectious uveitis (NOIU) is still corticosteroids, triamcinolone acetonide (TA) was the first intravitreally used agent in this subset of patients. Although it was very effective in controlling inflammation and improving the inflammation related complications, TA was found to have a high rate of intraocular complications and a relatively short half-life necessitating frequent reinjections. Other systemically used therapeutic options such as methotrexate and anti-tumor necrosis factor-α agents were also tried intravitreally. Additionally anti-vascular endothelial growth factor agents that are widely used intravitreally in the management of diabetic retinopathy and age related macular degeneration have become an option to control the uveitis related complications like macular edema, retinal and choroidal neovascularizations. Advances in biotechnology led to the slow release biodegradable implant era. These implants have a longer duration of action, which may help in decreasing the number of reinjections. Today two forms of implants have been approved for use in NOIU, Retisert (0.59 mg flucinolone acetonide, surgical intervention) and Ozurdex (0.7 mg dexamethasone, office based intervention). Studies dealing with newer agents (cyclosporine, LFG31, sirolimus) in the management of chronic NOIU are on the way. The search for ideal effective, safe and biocompatible intravitreal agents in the management of NOIU has not ended yet.

Optical coherence tomography based microangiography for quantitative monitoring of structural and vascular changes in a rat model of acute uveitis in vivo: a preliminary study

Uveitis models in rodents are important in the investigation of pathogenesis in human uveitis and the development of appropriate therapeutic strategies for treatment. Quantitative monitoring of ocular inflammation in small animal models provides an objective metric to assess uveitis progression and/or therapeutic effects. We present a new application of optical coherence tomography (OCT) and OCT-based microangiography (OMAG) to a rat model of acute anterior uveitis induced by intravitreal injection of a killed mycobacterial extract. OCT/OMAG is used to provide noninvasive three-dimensional imaging of the anterior segment of the eyes prior to injection (baseline) and two days post-injection (peak inflammation) in rats with and without steroid treatments. OCT imaging identifies characteristic structural and vascular changes in the anterior segment of the inflamed animals when compared to baseline images. Characteristics of inflammation identified include anterior chamber cells, corneal edema, pupillary membranes, and iris vasodilation. In contrast, no significant difference from the control is observed for the steroid-treated eye. These findings are compared with the histology assessment of the same eyes. In addition, quantitative measurements of central corneal thickness and iris vessel diameter are determined. This pilot study demonstrates that OCT-based microangiography promises to be a useful tool for the assessment and management of uveitis in vivo.

Novel dexamethasone-loaded nanomicelles for the intermediate and posterior segment uveitis

Development and characterization of dexamethasone (DEX)-encapsulated polymeric nanomicelles have been reported. A low molecular weight di-block copolymer was synthesized and characterized for its structure, molecular weights, critical micelle concentration (CMC), and cytotoxicity in ocular cells. In order to delineate the effects of drug-polymer interactions on drug solubilization in micelle core, a response surface methodology was generated with the help of SAS 9.02 (exploratory model). The method for preparing micelle was modified based on the results obtained from exploratory model. The formulation was optimized by response surface methodology (optimization model) to achieve DEX solubility of above 1 mg/mL. The optimized formulation was characterized for DEX solubility, nanomicelle size, polydispersity index, surface morphology, in vitro transport across conjunctival cell line, and ex vivo transport across excised rabbit sclera. Nanomicelles exhibited average sizes in range of 25-30 nm with unimodel size distribution and low polydispersity of 0.125. Nanomicelles increased DEX permeability by 2 times across conjunctival cell line and by 2.5 times across the excised rabbit sclera as compared to DEX suspension. A design of experiment (DOE) strategy was successfully applied to understand the effects of drug-polymer interaction on drug solubility. DOE was also employed to achieve optimal formulation with high DEX solubility. Nanomicellar formulation significantly enhanced DEX permeability across the excised rabbit sclera. Therefore, nanomicellar formulation may provide therapeutic levels in the back of the eye following topical administration.

Intravitreal steroids for the treatment of retinal diseases

Diabetic macular edema (DME), pseudophakic cystoid macular edema (CME), age-related macular degeneration (AMD), retinal vascular occlusion (RVO), and uveitis are ocular conditions related to severe visual impairment worldwide. Corticosteroids have been widely used in the treatment of these retinal diseases, due to their well-known antiangiogenic, antiedematous, and anti-inflammatory properties. Intravitreal steroids have emerged as novel and essential tools in the ophthalmologist's armamentarium, allowing for maximization of drug efficacy and limited risk of systemic side effects. Recent advances in ocular drug delivery methods led to the development of intraocular implants, which help to provide prolonged treatment with controlled drug release. Moreover, they may add some potential advantages over traditional intraocular injections by delivering certain rates of drug directly to the site of action, amplifying the drug's half-life, contributing in the minimization of peak plasma levels of the drug, and avoiding the side effects associated with repeated intravitreal injections. The purpose of this review is to provide an update on the use of intravitreal steroids as a treatment option for a variety of retinal diseases and to review the current literature considering their properties, safety, and adverse events.

Local therapies for inflammatory eye disease in translation: past, present and future

Despite their side-effects and the advent of systemic immunosuppressives and biologics, the use of corticosteroids remains in the management of patients with uveitis, particularly when inflammation is associated with systemic disease or when bilateral ocular disease is present. The use of topical corticosteroids as local therapy for anterior uveitis is well-established, but periocular injections of corticosteroid can also be used to control mild or moderate intraocular inflammation. More recently, intraocular corticosteroids such as triamcinolone and steroid-loaded vitreal inserts and implants have been found to be effective, including in refractory cases. Additional benefits are noted when ocular inflammation is unilateral or asymmetric, when local therapy may preclude the need to increase the systemic medication.

Implants in particular have gained prominence with evidence of efficacy including both dexamethasone and fluocinolone loaded devices. However, an appealing avenue of research lies in the development of non-corticosteroid drugs in order to avoid the side-effects that limit the appeal of injected corticosteroids. Several existing drugs are being assessed, including anti-VEGF compounds such as ranibizumab and bevacizumab, anti-tumour necrosis factor alpha antibodies such as infliximab, as well as older cytotoxic medications such as methotrexate and cyclosporine, with varying degrees of success. Intravitreal sirolimus is currently undergoing phase 3 trials in uveitis and other inflammatory pathways have also been proposed as suitable therapeutic targets. Furthermore, the advent of biotechnology is seeing advances in generation of new therapeutic molecules such as high affinity binding peptides or modified high affinity or bivalent single chain Fab fragments, offering higher specificity and possibility of topical delivery.

Interventions for the treatment of uveitic macular edema: a systematic review and meta-analysis

Background

Uveitic macular edema is the major cause of reduced vision in eyes with uveitis.

Objectives

To assess the effectiveness of interventions in the treatment of uveitic macular edema.

Search strategy

Cochrane Central Register of Controlled Trials, Medline, and Embase. There were no language or data restrictions in the search for trials. The databases were last searched on December 1, 2011. Reference lists of included trials were searched. Archives of Ophthalmology, Ophthalmology, Retina, the British Journal of Ophthalmology, and the New England Journal of Medicine were searched for clinical trials and reviews.

Selection criteria

Participants of any age and sex with any type of uveitic macular edema were included. Early, chronic, refractory, or secondary uveitic macular edema were included. We included trials that compared any interventions of any dose and duration, including comparison with another treatment, sham treatment, or no treatment.

Data collection and analysis

Best-corrected visual acuity and central macular thickness were the primary outcome measures. Secondary outcome data including adverse effects were collected.

Conclusion

More results from randomized controlled trials with long follow-up periods are needed for interventions for uveitic macular edema to assist in determining the overall long-term benefit of different treatments. The only intervention with sufficiently robust randomized controlled trials for a meta-analysis was acetazolamide, which was shown to be ineffective in improving vision in eyes with uveitic macular edema, and is clinically now rarely used. Interventions showing promise in this disease include dexamethasone implants, immunomodulatory drugs and anti-vascular endothelial growth-factor agents. When macular edema has become refractory after multiple interventions, pars plana vitrectomy could be considered. The disease pathophysiology is uncertain and the course of disease unpredictable. As there are no clear guidelines from the literature, interventions should be tailored to the individual patient.

Novel Intraocular Therapy in Non-infectious Uveitis of the Posterior Segment of the Eye

This article reviews the new clinically relevant data regarding the intraocular treatment of non-infectious uveitis. Triamcinolone acetonide is the most commonly used intravitreal corticosteroid for treatment of uveitis and uveitic macular oedema. The drug is available at low cost but it is associated with a high risk of raised intraocular pressure (IOP) and cataract and is not licensed for intraocular use. Dexamethasone implant (Ozurdex®) appears to have a better safety profile, and a slightly long-lasting effect than triamcinolone acetonide. Fluocinolone acetonide implant (Retisert®) implant allows the release of corticosteroids at a constant rate over a 3-year period, but it requires surgical placement and its use is associated with a very high risk of cataracts and raised intraocular pressure. Iluvien® is another fluocinolone acetonide implant that could represent a more convenient treatment option for such cases in the future as it can be inserted into the vitreous cavity through 25-gauge injector system in an outpatient setting. To circumvent the risks associated with corticosteroids use, non-corticosteroids related therapeutics including intravitreal methotrexate; anti-vascular endothelial growth factor treatments and intravitreal sirolimus have been recently developed.