Intravitreal silicone oil droplets after intravitreal drug injections

[Translated article] Syringes for intraocular administration: A systematic review

OBJECTIVE

The off-label use in clinical practice of non-approved syringes for intravitreal drug administration has resulted in the detection of silicone oil drops in the vitreous of some patients. This situation derives from the lack of approved syringes for intraocular use in the Spanish market. The aim of this work is to review the use of syringes for intraocular administration, as well as to search for alternatives that meet the legal requirements for these unmet needs.

METHOD

A systematic review was performed following the PRISMA 2020 guidelines by searching PubMed with the descriptors: (silicone) AND (syringes) AND ((intraocular) OR (intravitreal)) and filtering all existing publications from January 2006 to December 2023, including all those articles dealing with silicone oil release in intravitreal injections and analysing the possible consequences.

RESULTS

Sixty-eight results were found, 23 of which were excluded because they did not deal with the subject under study, leaving a total of 45 articles for the systematic review. These were classified according to the conclusions obtained in 4 groups: the adverse reactions produced by silicone; the administration technique; the physicochemical aspects of silicone release; and the characteristics of the medical device. After reviewing the current manufacturers and technical data sheets of commercialised syringes, the existing syringes for this use have been collected, finding 2 that will probably be commercialised in Spain at the beginning of 2024: Zero Residual™ 0.2 ml SiO-free and VitreJect® Ophthalmic.

CONCLUSIONS

From the results obtained, it can be interpreted that the use of syringes and needles with silicone for intravitreal use is a concern for health professionals due to the implications and consequences that may arise in patients, the most important being adverse reactions, so it is necessary to have silicone-free syringes on the market that are specific for intraocular use. Safety and legality in the use of intraocular syringes and needles is essential to guarantee ocular integrity and patient health.

Syringes for intraocular administration: Systematic review

OBJECTIVE

The off-label use in clinical practice of non-approved syringes for intravitreal drug administration has resulted in the detection of silicone oil drops in the vitreous of some patients. This situation derives from the lack of approved syringes for intraocular use in the Spanish market. The aim of this work is to review the use of syringes for intraocular administration, as well as to search for alternatives that meet the legal requirements for these unmet needs.

METHOD

A systematic review was performed following the PRISMA 2020 Guidelines by searching PubMed with the descriptors: "silicone" AND "syringes" AND ("intraocular" OR "intravitreal") and filtering all existing publications from January 2006 to December 2023, including all those articles dealing with silicone oil release in intravitreal injections and analysing the possible consequences.

RESULTS

Sixty-eight results were found, 23 of which were excluded because they did not deal with the subject under study, leaving a total of 45 articles for the systematic review. These were classified according to the conclusions obtained in 4 groups: the adverse reactions produced by silicone, the administration technique, the physicochemical aspects of silicone release, and the characteristics of the medical device. After reviewing the current manufacturers and technical data sheets of commercialized syringes, the existing syringes for this use have been collected, finding two that will probably be commercialized in Spain at the beginning of 2024: Zero Residual™ 0.2 ml SiO-free and VitreJect® Ophthalmic.

CONCLUSIONS

From the results obtained, it can be interpreted that the use of syringes and needles with silicone for intravitreal use is a concern for health professionals due to the implications and consequences that may arise in patients, the most important being adverse reactions, so it is necessary to have silicone-free syringes on the market that are specific for intraocular use. Safety and legality in the use of intraocular syringes and needles is essential to guarantee ocular integrity and patient health.

The Evolution of Triamcinolone Acetonide Therapeutic Use in Retinal Diseases: From Off-Label Intravitreal Injection to Advanced Nano-Drug Delivery Systems

Ophthalmic drug delivery to the posterior segment of the eye has been challenging due to the complex ocular anatomy. Intravitreal injection of drugs was introduced to deliver therapeutic doses in the posterior segment. Different posterior segment diseases including age-related macular degeneration, diabetic macular edema, retinal vein occlusions, uveitis, and cystoid macular edema, among others, have been historically treated with intravitreal corticosteroids injections, and more recently with intravitreal corticosteroids drug implants. Triamcinolone acetonide (TA) is the most frequently used intraocular synthetic corticosteroid. Using nanoparticle-based TA delivery systems has been proposed as an alternative to intravitreal injections in the treatment of posterior segment diseases. From these novel delivery systems, topical liposomes have been the most promising strategy. This review is oriented to exhibit triamcinolone acetonide drug evolution and its results in treating posterior segment diseases using diverse delivery platforms.

Silicone Oil Droplet Over the Optic Nerve Head After Intravitreal Injections

This case report discusses the finding of a silicone oil droplet over the optic nerve head of a patient with a history of multiple intravitreal injections.

Incidence of ocular hypertension after anti-VEGF injections: examining the effect of drug filtration and silicone-free syringes

OBJECTIVE

To examine the difference in incidence of ocular hypertension (OHT) following the introduction of filtered anti-vascular endothelial growth factor (anti-VEGF) medication in silicone-free syringes.

DESIGN

Retrospective cohort study.

METHODS

A retrospective review of consecutive treatment-naive patients receiving intravitreal anti-VEGF injections in a group practice was performed. Data from the cohort receiving nonfiltered anti-VEGF in insulin syringes (IS group) was collected from June 2015. Data from the cohort receiving filtered anti-VEGF in silicone-free syringes (SFS group) was collected from June 2019. Follow up data were collected at 1 year. Exclusion criteria included prior anti-VEGF treatment, known glaucoma or diagnosis of glaucoma suspect before anti-VEGF treatment, neovascular glaucoma, steroid use, or vitrectomy during follow-up. Primary outcome was the cumulative incidence of intraocular pressure (IOP) > 21 mmHg and IOP ≥ 30 mm Hg at any follow-up visit. The use of IOP lowering therapy was also recorded.

RESULTS

The mean age (71 ± 13 years), mean number of injections (9.6 ± 2.7), and median follow-up time (392 ± 57 days) were similar between groups. The incidence of IOP ≥ 21 mm Hg was 34% (34/100) in the IS group and 15% (15/100) in the SFS group (p = 0.025). The incidence of IOP ≥ 30 mm Hg was 8% (8/100) in the IS group and 0% (0/100) in the SFS group (p =0.004). The incidence of IOP-lowering therapy was 13% in the IS group and 0% in the SFS group (p =0.0002).

CONCLUSION

The incidence of OHT and treatment with IOP-lowering therapy significantly decreased after the introduction of filtered anti-VEGF medication and silicone-free syringes.

Ocular Injection Techniques for Retinitis Pigmentosa: Intravitreal, Subretinal, and Suprachoroidal

Ocular gene therapy represents an emerging and promising therapeutic approach for the treatment of several of the inherited retinal diseases. Currently, the focus has been to investigate monogenic inherited retinal disorders. Genetic and cellular therapies can be delivered to the eye by various injection techniques, including those that are intravitreal, subretinal, and suprachoroidal. Each of these three delivery methods are discussed with regard to their historical background, indications, surgical steps, and follow-up.

A Silicone Oil-Free Syringe Tailored for Intravitreal Injection of Biologics

Intravitreal injections (IVI) of biologics targeting vascular endothelial growth factor (anti-VEGF) led to a paradigm shift in the management and prognosis of prevalent retinal conditions. Yet, IVI are typically performed with syringes that are neither developed nor approved for this purpose. Notably, syringes lubricated with silicone oil (SiO) are extensively used despite multiple reports showing that such syringes can cause deposition of SiO droplets in the vitreous body and patient discomfort. Thus, there is a need for SiO-free substitutes specifically tailored for IVI. Here, we report on the development and testing of such a syringe. This syringe has no dead volume, and its design allows for high-accuracy dosing. Also, it permits pharmaceutical compounding and storage of bevacizumab, ranibizumab, and aflibercept for up to 30 days without compromising their functional binding or transport properties. Finally, the new syringe demonstrated a favorable safety profile regarding release of SiO compared to SiO lubricated alternatives, including commercially prefilled syringes. Accordingly, the newly developed syringe is an appealing alternative for IVI.

Intravitreal Corticosteroid Implantation in Diabetic Macular Edema: Updated European Consensus Guidance on Monitoring and Managing Intraocular Pressure

Intravitreal therapy for diabetic macular edema can, in susceptible patients, increase intraocular pressure (IOP). As uncontrolled IOP can potentially be sight threatening, monitoring is an essential component of patient management. It can be challenging for retina specialists to ensure that monitoring is rigorous enough to detect and resolve any potential problems at the earliest opportunity without it also being overburdensome for patients who have the lowest risk of developing an IOP rise. We have developed dynamic algorithms that: (1) tailor the frequency and extent of monitoring according to individual susceptibility and current IOP and (2) assist retina specialists in deciding when they should consider a referral to a glaucoma specialist. One algorithm is for patients with a relatively low susceptibility to developing an IOP rise (those whose baseline IOP is < 22 mmHg and who do not have a history of IOP events). Depending on their first post-implantation IOP check, the algorithm classifies them as: low risk if IOP remains < 22 mmHg; medium risk if IOP is 22-25 mmHg and any rise from baseline is < 10 mmHg; or high risk if IOP is > 25 mmHg or any rise from baseline is ≥ 10 mmHg. Thereafter, the algorithm guides on the frequency and extent of monitoring required in each of these groups and, if IOP rises or falls during treatment, patients may move up or down the risk groups accordingly. A different algorithm is provided for patients who are more susceptible to developing an IOP rise (those with a baseline IOP of ≥ 22 mmHg or a prior history of an IOP event). These patients need monitoring more closely so this algorithm has only medium- or high-risk classifications. These algorithms update the previous monitoring guidance by Goñi et al. (Goñi et al. in Ophthalmol Ther 5:47-61, 2016).

Silicone oil-free syringes, siliconized syringes and needles: quantitative assessment of silicone oil release with drugs used for intravitreal injection

PURPOSE

This study aimed to quantify the amount of silicone oil (SO) released across a variety of syringe and needle models routinely used for intravitreal injection.

METHODS

The release of SO was assessed in eight models of syringes, two of which were reported to be 'SO-free', and eleven models of needles with unknown SO content. To evaluate SO release within the context of anti-VEGF therapeutics, syringes were evaluated using aflibercept, bevacizumab, buffer, ziv-aflibercept and formulation buffer. All syringe tests were performed with or without agitation by flicking for syringes. Needles were evaluated without agitation only. Samples were fluorescently labelled to identify SO, and triplicate measurements were collected using imaging flow cytometry.

RESULTS

Seven out of 8 syringe models showed a statistically significant increase in the SO particle count after agitation. The two SO-free syringe models (HSW Norm-Ject, Daikyo Crystal Zenith) released the least SO particles, with or without agitation, whereas the BD Ultra-Fine and Saldanha-Rodrigues syringes released the most. More SO was released when the syringes were prefilled with formulation buffer than with ziv-aflibercept. Syringes filled with aflibercept and bevacizumab had intermediate levels. Agitation increased the release of SO into each of the drug solutions. Silicone oil (SO) was detected in all needles.

CONCLUSIONS

Agitation of the syringe by flicking leads to a substantial increase in the number of SO particles. Silicone oil (SO)-free syringes had the best performance, but physicians must also be aware that needles are siliconized and also contribute to the injection of SO into the vitreous.

Evaluation of the prevalence of silicone oil droplets in the vitreous in patients treated with multiple intravitreal drug injections

Background. At present, intraocular drops of silicone oil, which is a lubricant for disposable syringes used for intravitreal injections, are being actively studied. Among the undesirable effects of their presence are patient’s complaints of visual discomfort associated with floating opacities, as well as a potential connection with episodes of intraocular inflammation and increased intraocular pressure.

The aim: to assess the prevalence of silicone oil droplets in the vitreous in patients treated with multiple intravitreal injections.

Materials and methods. A single-center retrospective cohort study was carried out. Inclusion criterion: treatment with multiple (at least 5) intravitreal injections of drug solutions performed according to registered indications. The study group consisted of 86 eyes of 85 patients (56 women, 29 men; age – from 36 to 89 y.o., average – 71.7 y.o.), who received an average of 13.2 injections of solutions of various drugs.

Results. Drops of silicone oil were detected by biomicroscopy in 57 eyes (66.28 %) and by ultrasonography in 76 (88.37 %). The coincidence of the results of applying the methods was recorded in 73.26 % of observations. Seven (8.1 %) patients had characteristic complaints. Four patients (4.7  %) had a history of aseptic vitreitis. The  hypothesis was  confirmed that the possibility of silicone oil droplets getting into the vitreous increases with the number of intravitreal injections. A similar relationship was established in relation to the possibility of the appearance of characteristic complaints in patients due to the presence of drops and episodes of aseptic vitreitis.

Conclusion. The release of drops of silicone oil from syringes during intravitreal injections is an urgent problem that requires further study. In the Russian Federation, the situation is aggravated by the lack of prefilled syringes with drugs approved for administration into the eye cavity, as well as the lack of syringe models designed for use in ophthalmology. 

Silicone microbubbles after anti-vascular endothelial growth factor injections in patients with wet age-related macular degeneration: incidence, quantification and secondary optical coherence tomography artfacts

PURPOSE

To report the incidence and quantity of silicone oil microbubbles and the relationship with the number of intravitreal anti-vascular endothelial growth factor (VEGF) injections and evaluate if microbubbles induce artefacts on optical coherence tomography (OCT) images.

METHODS

Observational, descriptive, cross-sectional study. Patients with wet age-related macular degeneration were included who had been treated for 1 year minimally with anti-VEGF injections repackaged in the hospital pharmacy. Detection and quantification of silicone microbubbles by mydriatic biomicroscopic examination were conducted 1 month after the last injection. The numbers of microbubbles were quantified on a scale of 0-3: 0, none; 1 scarce (1-10 microbubbles); 2 moderate (10-30); or 3 numerous (>30). Shadowing on OCT images was classified as 0-3: 0, none; 1 obscuring some retinal layers; 2 obscuring all retinal layers; or 3 obscuring the retinal thickness.

RESULTS

The study included 142 eyes of 98 patients (mean age, 82.4 years + 7.3; range, 65-97) treated with 2377 injections. Microbubbles were detected in 127 (89.4%) eyes, 62 (43.6%) with numerous microbubbles and 36 (25.4%) and 29 (20.4%), respectively, with scarce and moderate numbers. A positive correlation was found between the numbers of injections and intravitreal silicone (rho, 0.7). Optical coherence tomography (OCT) artefacts were detected in 11 eyes; the artefacts obscured all retinal layers in three eyes. No significant relationship could be established between the appearance of floaters and the microbubbles.

CONCLUSION

The presence and number of silicone microbubbles were correlated with the number of intravitreal injections. Microbubbles can produce OCT artefacts, which can hinder the treatment decision.

Silicone oil droplets in the vitreous after intravitreal injections: review of literature with clinical examples

Currently, intravitreal injections are firmly in the lead as a drug delivery method for treatment of a wide range of eye diseases. With the accumulation of clinical material, knowledge about the complications and side effects of this technique is expanding. One of the undesirable phenomena that has been actively studied recently is the ingress of silicone oil droplets from single-use syringes and needles used to perform the procedure into the vitreous cavity of patients eyes. The analysis of the results of original studies on this issue is carried out, and the currently available practical recommendations aimed at reducing the risk of this complication are presented. The article is illustrated with original clinical examples. It can be concluded that the penetration of silicone oil into the eye cavity during intravitreal injections is an urgent problem of modern ophthalmology that requires further investigation and solution.

Ocular Therapeutics and Molecular Delivery Strategies for Neovascular Age-Related Macular Degeneration (nAMD)

Age-related macular degeneration (AMD) is the leading cause of vision loss in geriatric population. Intravitreal (IVT) injections are popular clinical option. Biologics and small molecules offer efficacy but relatively shorter half-life after intravitreal injections. To address these challenges, numerous technologies and therapies are under development. Most of these strategies aim to reduce the frequency of injections, thereby increasing patient compliance and reducing patient-associated burden. Unlike IVT frequent injections, molecular therapies such as cell therapy and gene therapy offer restoration ability hence gained a lot of traction. The recent approval of ocular gene therapy for inherited disease offers new hope in this direction. However, until such breakthrough therapies are available to the majority of patients, antibody therapeutics will be on the shelf, continuing to provide therapeutic benefits. The present review aims to highlight the status of pre-clinical and clinical studies of neovascular AMD treatment modalities including Anti-VEGF therapy, upcoming bispecific antibodies, small molecules, port delivery systems, photodynamic therapy, radiation therapy, gene therapy, cell therapy, and combination therapies.

Aflibercept clearance through the drainage system in a rat model

Background

As intravitreal anti-VEGF injections became the mainstay of treatment for many retinal diseases, the cause of a secondary sustained elevated intraocular pressure is still unclear. The aim of our study was to study the clearance of Aflibercept from the anterior chamber angle, in a rat model, to test if an aggregation exists.

Methods

Choroidal neovascular lesions (CNV) were induced in the right eye of 12 brown Norway rats, using indirect laser ophthalmoscope. Intravitreal Aflibercept injection (0.12 mg/3 µl) was performed 3 days after CNV induction. Rats were euthanized at predetermine time intervals of 3, 6, 24 and 48 h post injection, with immediate enucleation for histological analysis with H&E and immunofluorescence staining. Aflibercept molecules were stained with red fluorescence thanks to the formation of the immune complex Aflibercept-Rabbit anti human IgG-Anti rabbit antibodies-Cy3.

Results

Immediately after the injection, a strong fluorescence signal was detected, indicating the presence of Aflibercept in the iridocorneal angle. At 3- and 6-h interval a strong signal of Aflibercept was still seen. Six hours post injection, the signal was highly concentrated in Schlemm’s canal. In the 2 eyes harvested 24 h post Aflibercept injection, red fluorescence signal intensity was decreased in one eye, occupying mainly intra scleral venous plexuses, and absent in the other eye. At 48 h there was no fluorescence signal, confirming complete clearance of Aflibercept.

Conclusions

In our rat model, a complete clearance of Aflibercept from the anterior chamber angle, was seen 48 h after the injection. This finding refutes the theory of possible connection between IOP elevation and mechanical obstruction. Evacuation time of Aflibercept through the angle is of the same magnitude as that of Bevacizumab in the same rat model.

Cluster of symptomatic silicone oil droplets following intravitreal injections: a 1-year observational study

Objective

To describe a cluster of symptomatic intravitreal silicone oil (SiO) droplets following intravitreal injections (IVIs) and assess the effect of switching to a SiO-free syringe.

Methods and analysis

Observational quality registry study of patients receiving IVI at a large Norwegian ophthalmology centre between April 2018 (start of cluster) and November 2019 (1 year after switching to SiO-free syringes). At onset, anti-vascular endothelial growth factor drugs were administered using SiO-containing insulin syringes. From November 2018, SiO-free syringes were implemented. Spontaneously reported symptomatic SiO cases were confirmed by slit-lamp examination. A follow-up interview was performed after 1 year, assessing visual complaints. The prevalence of non-symptomatic cases was assessed in a sample of 50 eyes from 50 consecutive IVI patients.

Results

Among 13 429 IVIs, 50 eyes of 46 patients (29 women) with symptomatic intravitreal SiO droplets were identified. Forty-one patients reported floaters at regular appointments, whereas five patients contacted the department regarding symptoms between scheduled appointments. After 1 year, 34 patients (79%) still experienced floaters, 21 (49%) reported reduced symptoms and 3 (7%) reported worsened symptoms. Eighteen patients (42%) reported being bothered, and eight (18.6%) reported that their lives were negatively affected by the floaters. Among 50 non-symptomatic eyes that had received IVI during the same period, intravitreal SiO was found in 34 (68%). No cases of symptomatic intravitreal SiO droplets were identified after switching to SiO-free syringes.

Conclusion

Symptomatic intravitreal SiO following IVI can cause significant and prolonged distress for affected patients. It can be avoided by using SiO-free syringes.

Chemical-gas Sterilization of External Surface of Polymer-based Prefilled Syringes and Its Effect on Stability of Model Therapeutic Protein

To reduce the risk of infection during intravitreal injections, the external surface of prefilled syringes (PFSs) must be sterilized. Usually, ethylene oxide (EO) gas or vaporized hydrogen peroxide (VHP) is used for sterilization. More recently, nitrogen dioxide (NO₂) gas sterilization has been developed. It is known that gas permeability is approximately zero into glass-PFSs. However, polymer-PFSs (P-PFSs) have relatively high gas permeability. Therefore, there are concerns about the potential impact of external surface sterilization on drug solutions in P-PFSs. In this study, P-PFSs [filled with water for injection (WFI) or human serum albumin (HSA) solution] were externally sterilized using EO, VHP, and NO₂ gases. For the WFI-filled syringes, the concentration of each gas that ingressed into the WFI was measured. For the HSA solution-filled syringes, the physical and chemical degradation of HSA molecules by each sterilant gas was quantified. For the EO- or VHP-sterilized syringes, the ingressed EO or hydrogen peroxide (H₂O₂) molecules were detected in the filled WFI. Additionally, EO-adducted or oxidized HSA molecules were observed in the HSA-filled syringes. In contrast, the NO₂-sterilized WFI-filled syringes exhibited essentially immeasurable ingressed NO₂, and protein degradation was not detected in HSA-filled syringes.

Comparison of Syringes With Intravitreal Anti-VEGF Drugs: Particle Burden and Protein Aggregates in Brolucizumab, Aflibercept and Bevacizumab

Purpose

In a benchwork particle counting analytical evaluation, the number and type of particles in intravitreal injection formulations of three different agents against vascular endothelial growth factor were investigated.

Methods

Commercially available ready-to-use aflibercept and brolucizumab glass syringes, vials containing bevacizumab (off-label use in ophthalmology), and repackaged ready-to-use plastic syringes containing bevacizumab were tested without filtration. Total visible, subvisible, and nanoparticles numbers and size distributions were quantified using light obscuration, flow imaging, resonant mass measurement (RMM), tunable resistive pulse sensing, and dynamic light scattering.

Results

Repackaged bevacizumab showed overall low particle numbers, aflibercept showed high numbers of micrometer sized particles but low nanoparticle numbers, brolucizumab showed low to moderate numbers of micrometer sized particles but high nanoparticle numbers. RMM measurements identified particles in the nanometer range as either proteinaceous or silicon oil; the nature of the other particles was not further evaluated.

Conclusions

Repackaged bevacizumab shows no inferior particle quality compared to ready-to-use products. It is relevant to study nanoparticle load of the products as the micrometer-sized particle numbers do not in all cases correlate to nanoparticle counts. Particularly for the high concentration product Beovu (brolucizumab), high nanoparticle numbers were found despite low numbers of micrometer sized particles. Silicone oil droplets did not account for high particle numbers as the measured numbers were low.

Translational Relevance

Different side effects are registered in different frequencies with different intravitreal anti-VEGF-drugs and syringes, which are applied by injection by small 30G needles through the sclera directly to the intravitreal cavity. The study of nanoparticles and silicone oil droplets may be able to contribute to narrowing down the causes.

Incidence of elevated intraocular pressure after intravitreal injection in Japanese patients with age-related macular degeneration

The purpose of this study was to report the incidence of elevated intraocular pressure (IOP) after intravitreal injection (IVI) of anti-vascular endothelial growth factor (VEGF) in Japanese patients with age-related macular degeneration (AMD). A retrospective study of chart review of patients who underwent ≥ 10 intravitreal anti-VEGF injections between April 2009 and December 2019 was conducted. Elevated IOP was defined as IOP ≥ 25 mmHg at one visit. Cases with elevated IOP resulting from IVI were identified. Furthermore, the association between elevated IOP and some parameters, as the risk factors that influence elevated IOP, was investigated. A total of 402 eyes of 370 patients were included in this study. Twenty-eight eyes of 26 patients (7.0%) were identified as cases with elevated IOP after IVI. The mean time of elevation after baseline was 50.6 ± 26.5 months. History of glaucoma (p = 0.021; odds ratio, 5.85), treatment modality (p = 0.019; odds ratio, 6.32), and total number of injections (p = 0.003; odds ratio, 1.03) were significantly associated with elevated IOP. A late complication of elevated IOP is associated with IVI in patients with AMD. Particularly, history of glaucoma and treat and extend regimen with frequent injections were found to be risk factors of elevated IOP.

In-vitro assessment of release of silicone oil droplets with the use of variety of syringes and needles used in intravitreal injections

PURPOSE

To assess the variability of silicone oil (SO) particles released across syringes from the same lot and the role of different needle gauges.

MATERIALS AND METHODS

Four syringe models and six needle models were assessed for SO release. About 50 microliters of a buffer solution were loaded into the syringe, needle or syringe/needle setup. The data were analyzed by imaging flow cytometry with fluorescently labeling for SO.

RESULTS

All syringe models had a high coefficient of variation in SO release across syringes from the same lot. The amount of SO was significantly greater in the syringe when the needle was attached. SO particles with the BD 30G needle attached to the syringe were statistically greater than the 27G counterpart (p = 0.005). None of the other comparisons was statistically different. Finally, the number of SO particles was higher in the syringe/needle setup than in needles only (p = 0.0024).

CONCLUSION

We found a high variability in SO content across syringes from the same lot. Additionally, there was no clear association between needle gauge and the number of SO particles, as well as their coefficient of variation. Finally, the needles accounted for a small number of SO particles in comparison to the combined syringe-needle setup.

Drug-related adverse effects of antivascular endothelial growth factor agents

PURPOSE OF REVIEW

Antivascular endothelial growth factor (VEGF) agents have provided historic therapeutic breakthroughs in the treatment of retinal disease. New anti-VEGF agents are emerging for the treatment of retinal vascular diseases. Both systemic and ocular adverse effect need to be understood in managing patients. This review aims to highlight the adverse effects seen with routine use of bevacizumab, ranibizumab and aflibercept, as well as with new medications such as brolucizumab and abicipar.

RECENT FINDINGS

We review the recent findings of intraocular inflammation (IOI) of brolucizumab and abicipar in the context of the efficacy and safety reported with the routine anti-VEGF agents. Specifically, brolucizumab has been reported to cause occlusive retinal vasculitis in the setting of IOI, which has not been seen in other anti-VEGF medications. In addition, abicipar appears to cause IOI at a higher rate of patients than other anti-VEGF agents have previously.

SUMMARY

Newer anti-VEGF agents pose a significant risk of adverse events not seen with routine anti-VEGF agents.

PARTICULATE MATTER FROM SYRINGES USED FOR INTRAVITREAL INJECTIONS

BACKGROUND

Syringes containing anti-vascular endothelial growth factor drugs to treat retinal diseases are prepared in different ways by various parties with syringe selection, preparation, and storage conditions affecting the risk of injecting particles into the vitreous. This study examines particle loads from various syringes over time.

METHODS

Four syringes were studied: two plastic transfer syringes lubricated with silicone oil or oleamide, a glass syringe with baked-on silicone, and a lubricant-free polymer syringe. Syringes were rinsed with water or filled with buffer and analyzed over time; particles were quantified by flow imaging. Particle formation in a bevacizumab formulation was also characterized.

RESULTS

Insulin syringes consistently showed very high particle counts. Oleamide-lubricated syringes had substantially fewer particles, but showed appreciable increases over time (leading to visible particles). Baked-on silicone glass syringes and lubricant-free polymer syringes both showed low particle levels ≥10 μm. Lubricant-free syringes showed the lowest particle levels ≥1 μm and the lowest particle levels with bevacizumab agitation.

CONCLUSION

Syringes have different intrinsic particle loads which can contribute to particle loads in the delivered drug. Oleamide-lubricated transfer syringes, commonly used for bevacizumab repackaging, have time-dependent particle loads and are associated with the formation of visible particles beyond 30 days of storage.

Intraocular Pressure Changes after Intravitreal Bevacizumab or Ranibizumab Injection: A Retrospective Study

Purpose

To determine intraocular pressure (IOP) changes after intravitreal bevacizumab or ranibizumab injection administered for various retinal disorders.

Methods

A retrospective chart review of 796 eyes of 574 patients receiving intravitreal ranibizumab (0.5 mg) and/or bevacizumab (1.25 mg) injection for different retinal diseases from March 2009 to December 2016 was performed. Ocular hypertension (OHT) was defined as IOP >21 mmHg or an increase in IOP of >5 mmHg from the baseline. IOP at the baseline and at various time periods after the injection was evaluated in the injected eyes and fellow control eyes.

Results

One hundred and thirty-one eyes received either a single dose of bevacizumab or ranibizumab intravitreal injection unilaterally, 222 patients received single injection in both the eyes (n = 444 eyes), and 221 eyes received multiple doses of the injection. OHT was noted in 11 eyes (1.38%), of which 3 eyes (0.38%) had transient OHT and 8 eyes (1%) had delayed and sustained OHT and among them, 3 eyes (0.4%) progressed to glaucoma. Preinjection IOP was significantly higher in the treated eyes when compared to the control untreated eyes (P = 0.006).

Conclusions

Incidence of delayed and sustained OHT is low after a single or multiple intravitreal bevacizumab and ranibizumab injections. Clinicians should be aware of possibility of OHT or glaucoma after the procedure.

High particle variability across siliconized and oil-free syringes and needles from the same lots

Previous studies have reported silicone oil (SO) applied to needles and syringes in the vitreous of patients after intravitreal injections. We evaluated four syringes (SR 1-mL insulin, Saldanha-Rodrigues; BD 1-mL Tuberculin Slip Tip, Becton–Dickinson; BD Ultra-Fine 0.3 mL, HSW Norm-Ject Tuberculin, Henke Sass Wolf) and 10 needles (BD PrecisionGlide 27- and 30-gauge (G); BD Eclipse and JBP Nanoneedle 27-, 30-, 33- and 34-G; TSK Invisible Needle and 27 and 30-G Steriject Control Hub). The protein-free buffer samples injected into the syringes and needles under study were collected in an Eppendorf tube and taken to Flow imaging microscopy, that characterized the concentration and morphology of the microsized particles. The number of particles was analyzed. The coefficients of variation (CV) were the primary outcome. The Feltz and Miller test compared the CVs. The significance level was 5%. Numerous particles and high CVs were associated with both devices, needles and syringes; the comparisons among them did not reach significance. The BD Ultrafine 0.3 mL syringe (149.7%) had the highest CV and the SO-free HSW Norm-Ject (66.4%) syringe the lowest, and the TSK Invisible needle (149.5%) had the highest and the BD Precision Glide 30G needle (35.9%) needle the lowest. In conclusion, particle release, including those with SO morphology, varied greatly among instruments, even from the same lots, which is relevant considering that fewer particles are injected into some eyes compared with others.

Observation of Silicone Oil Within the Vitreous and Sclera Following Intravitreal Administration of Biotherapeutics Using Insulin Syringes in Cynomolgus Monkeys

Silicone oil droplets have been reported in the eyes of human patients following intravitreous (IVT) injections with several marketed biotherapeutic products. Intravitreous administration of a novel biotherapeutic in a 14-week cynomolgus monkey study using insulin syringes was associated with 2, non-test-article-related phenomena: "vitreous floater/clear sphere" on indirect ophthalmoscopy and intrascleral "foreign material near injection track" on histopathology. Retrospective analysis of 81 other preclinical studies of IVT administration of novel biotherapeutics found a greater frequency of clear spheres in monkey IVT studies using insulin syringes and formulations containing polysorbate. We were able to correlate microscopic findings of clear circular to oval areas in the sclera near the injection track with an energy-dispersive X-ray spectroscopy (EDS) signal for silicon at the same location in the sclera. These observations provide further evidence that silicone lubricant in insulin syringes/needles is the source of clear spheres noted in the vitreous and foreign material noted near the injection track in the sclera. Although considered inert and toxicologically insignificant, silicone deposition within the eye should form part of the risk-benefit equation in a clinical setting.

Applying Pattern Recognition as a Robust Approach for Silicone Oil Droplet Identification in Flow-Microscopy Images of Protein Formulations

Discrimination between potentially immunogenic protein aggregates and harmless pharmaceutical components, like silicone oil, is critical for drug development. Flow imaging techniques allow to measure and, in principle, classify subvisible particles in protein therapeutics. However, automated approaches for silicone oil discrimination are still lacking robustness in terms of accuracy and transferability. In this work, we present an image-based filter that can reliably identify silicone oil particles in protein therapeutics across a wide range of parenteral products. A two-step classification approach is designed for automated silicone oil droplet discrimination, based on particle images generated with a flow imaging instrument. Distinct from previously published methods, our novel image-based filter is trained using silicone oil droplet images only and is, thus, independent of the type of protein samples imaged. Benchmarked against alternative approaches, the proposed filter showed best overall performance in categorizing silicone oil and non-oil particles taken from a variety of protein solutions. Excellent accuracy was observed particularly for higher resolution images. The image-based filter can successfully distinguish silicone oil particles with high accuracy in protein solutions not used for creating the filter, showcasing its high transferability and potential for wide applicability in biopharmaceutical studies.

Unexplained Visual Loss After Silicone Oil Removal: A 7-Year Retrospective Study

Introduction

Unexplained visual loss after removal of silicone oil from the eye has been described. The purpose of this study is to determine the incidence of unexplained loss of visual acuity after SO removal and to provide possible explanations for this phenomenon.

Methods

This retrospective study included patients that underwent vitreoretinal surgery, at Centro Hospitalar São João, between January of 2012 and October of 2018. Inclusion criterion was vitreoretinal surgery in which the chosen endotamponade was SO, followed by removal of SO and exchange with balanced salt solution (BSS) or air. After SO removal, patients with documented loss of best corrected visual acuity (BCVA) on two or more Snellen lines were analyzed and patients in which the cause of the visual loss was identified, namely OHT (intraocular pressure > 21 mmHg), retinal re-detachment, glaucoma, retinal proliferative membrane formation, or corneal decompensation, were excluded. All patients with unexplained visual loss underwent spectral domain optical coherence tomography (SD-OCT) to exclude causes of visual reduction such as cystoid macular edema, epiretinal membrane, or ellipsoid/interdigitation zone disruption. A p value less than 0.05 was considered statistically significant.

Results

A total of 46 eyes underwent SO tamponade and SO removal during the study period. In 34.8% of the cases (n = 16) there was visual acuity loss in at least two Snellen lines. Of 46 eyes, 23.9% (n = 11) showed vision loss due to known secondary causes. Unexplained loss of visual acuity after SO removal occurred in 10.9% of cases. OHT during silicone endotamponade (p = 0.046) and silicone emulsification (p = 0.001) were identified as factors associated with unexplained visual loss after SO removal.

Conclusion

Unexplained loss of visual acuity after SO removal occurred in 10.9% of cases. OHT during silicone endotamponade and SO emulsification were identified as important factors in the ethology of this phenomenon.

Characterization of Polymeric Syringes Used for Intravitreal Injection

Intravitreal (IVT) injection is currently the state of the art for drug delivery to the back of the eye. Drug Products (DP) intended for IVT injections usually pose challenges such as a very low injection volume (e.g. 50 μL) and high injection forces. DPs in vials are typically transferred and injected using disposable polymer syringes, which can feature a silicone oil (SO) coating. In our syringe in-use study, we compared dead volume, total SO content and SO layer distributions of three IVT transfer injection syringes. We assessed multiple potential impact factors such as protein concentration, needle gauge, injection speed, surfactant type and the impact of the in-use hold time on sub-visible particle (SvP) formation and injection forces. Pronounced differences were observed between the syringes regarding SvP generation. Siliconized syringes showed higher SvP counts as compared to non-siliconized syringes. In some cases injection forces exceeded 20 N, which caused needles to burst off during injection. The syringes also showed relevant differences in total SO content and dead volume. In conclusion, specific consideration in the selection of an adequate transfer injection syringe are required. This includes extensive testing and characterization under intended and potential in-use conditions and the development of in-use handling procedures.

Clinical features, management and outcomes of patients with sterile endophthalmitis associated with intravitreal injection of antivascular endothelial growth factor

PURPOSE

Analyze clinical features, management and outcomes of patients with sterile endophthalmitis associated with intravitreal antivascular endothelial growth factor.

METHODS

Observational retrospective case series of patients with sterile endophthalmitis following anti-VEGF intravitreal injections. Clinical data of patients treated with intravitreal anti-VEGFs during one year have been revised. Those who have presented an episode of sterile endophthalmitis are analyzed and their causality and management are studied.

RESULTS

Seven patients have had a sterile endophthalmitis onset within 4days after intravitreal injection (aflibercept n=5 and ranibizumab n=2). These patients have some active neovascular condition: age related macular degeneration (n=4), myopic choroidal neovascularization (n=1) or macular edema: diabetic macular edema (n=1), branch retinal vein occlusion (n=1). Shared signs and symptoms included painless vision loss, anterior chamber and vitreous cell and lack of hypopyon. In all patients, visual acuity returned to within one line of baseline acuity.

CONCLUSION

Differentiating cases of sterile from infectious endophthalmitis may be challenging. It is crucial to differentiate both entities as a good diagnosis determines the visual prognosis. We should be aware of minimal inflammation after repeated intravitreal injections in order to establish the adequate treatment.

Adherence of Intravitreal Silicone Oil Bubbles to a Silicone Intraocular Lens

The authors present a case of diffuse silicone oil deposits from intravitreal anti-vascular endothelial growth factor injections adhering to the posterior capsule of a silicone intraocular lens. [Ophthalmic Surg Lasers Imaging Retina. 2020;51:307.].

Critical analysis of techniques and materials used in devices, syringes, and needles used for intravitreal injections

Intravitreal injections have become the most commonly performed intraocular treatments worldwide. Because intravitreal injections may induce severe adverse events, such as infectious and noninfectious endophthalmitis, cataract, ocular hypertension, vitreous hemorrhage, or retinal detachment, appropriate awareness of the materials and techniques used are essential to reduce these sight-threatening complications. This review provides insights into the needles, syringes, silicone oil coating, sterilization methods, devices to assist intravitreal injections, scleral piercing techniques using needles, syringe handling, anesthesia, and safety issues related to materials and techniques. It is paramount that physicians be aware of every step involved in intravitreal injections and consider the roles and implications of all materials and techniques used. The ability to understand the theoretical and practical circumstances may definitely lead to state-of-the-art treatments delivered to patients. The most important practical recommendations are: choosing syringes with as little silicone oil as possible, or, preferably, none; avoiding agitation of syringes; awareness that most biologics (e.g., antiangiogenic proteins) are susceptible to changes in molecular properties under some conditions, such as agitation and temperature variation; understanding that improper materials and techniques may lead to complications after intravitreal injections, e.g., inflammation; and recognizing that some devices may contribute to an enhanced, safer, and faster intravitreal injection technique.

Issues with Intravitreal Administration of Anti-VEGF Drugs

Purpose

To provide an update of summary of risk factors and side effects of long-term use and contamination of intravitreal anti-VEGF injections.

Methods

We reviewed relevant publications of the topic of contamination of anti-VEGF injections and long-term side effects due to this reason.

Results

Due to the long-term use of anti-VEGF drugs and the higher number of injections worldwide, various studies have shown side effects in recent years, ranging from increased intraocular pressure to visual disturbing silicone oil vesicles in the vitreous cavity. Several studies have demonstrated that both the drug and the processing, storage, environmental factors and the material and design of the syringes have a decisive influence on these side effects.

Conclusion

The risks of deposits from syringes in the eye can be significantly reduced by various optimizations in transport, storage and syringe and cannula selection.

Agitation of the syringe and release of silicone oil

BACKGROUND/OBJECTIVES

To investigate whether agitation promotes the release of silicone oil by different models of syringe used for intravitreal injection.

METHODS

This lab study analyzed eight syringe models by light microscopy for the release of silicone oil under agitation (flick), without agitation, and positive controls. Fourier-Transform Infrared Spectroscopy (FTIR) was performed to identify the molecular compounds inside the syringes.

RESULTS

A total of 240 syringes were analyzed. The presence of silicone oil droplets was observed in all positive controls. When agitated by flicking, 100% of the samples of the syringes disclosed silicone oil, except the BD Plastipak syringe, which presented 40% of positivity. Without agitation, a smaller percentage of samples with silicone oil was observed. Agitation by flicking had a 265-fold greater chance of presenting oil droplets when compared with the syringes without agitation. There was a statistically significant difference between the three conditions (P < 0.05). Analysis of the tip of the plunger rubber by FTIR indicated the presence of polysiloxane (silicone oil) in all models of syringe.

CONCLUSIONS

Agitation of the syringe promotes the release of silicone oil. It is recommended to improve the technique of injection and the manufacture of specific syringes for ophthalmological use.

Incidence of Glaucoma or Ocular Hypertension After Repeated Anti-Vascular Endothelial Growth Factor Injections for Macular Degeneration

Purpose

To estimate the risk of glaucoma or sustained ocular hypertension (OHT) related to anti-vascular endothelial growth factor (VEGF) injections for age-related macular degeneration (AMD).

Design

Retrospective chart review.

Subjects

Patients who received unilateral anti-VEGF injections for AMD at the Wheaton Eye Clinic (IL).

Methods

Chart analysis was performed on 1095 patients, without prior glaucoma or OHT, who received unilateral anti-VEGF injections for AMD from 2005 to 2012, with data collected through 2013. Data collection included demographics, lens status, date and medication type of each injection, and the date of diagnosis of glaucoma or OHT by a treating glaucoma specialist, which was the main outcome measure. Rare events logistic regression was performed to determine the risk of disease development based on sex, lens status, and injection frequency.

Results

Unilateral glaucoma or sustained OHT developed in 42 patients over the course of follow-up, with 40 events in the injected eye only, 2 in the contralateral eye only. Statistical modeling predicted elevated risk for onset of glaucomatous disease with a higher maximum frequency of injections (p < 0.0001, odds ratio [OR] 2.18 for each additional injection over the most injection-intense 6 months for a given subject) and with phakic lens status (p = 0.0009, OR 0.33 for pseudophakia).

Conclusion

Our results show a significant risk for glaucoma or OHT development in patients undergoing repeated treatments with intravitreal anti-VEGF injections for AMD, establishing the first reliable connection between disease development and a period of high-frequency injections. In addition, we show a significantly increased risk of disease development in phakic patients, which we believe points to a mechanical explanation for this type of secondary glaucoma.

A new method for pharmaceutical compounding and storage of anti-VEGF biologics for intravitreal use in silicone oil-free prefilled plastic syringes

Intravitreal injections of antibody-based biologics targeting vascular endothelial growth factor (VEGF) are highly effective and have markedly decreased the risk of visual impairment associated with prevalent retinal diseases, such as neovascular age-related macular degeneration and diabetes macular oedema. The diseases are chronic in their nature, and most patients need long-term therapy to suppress disease activity. We previously reported a compounding method for repackaging and storage of aflibercept (Eylea), a commonly used anti-VEGF biologic, in silicone oil-coated plastic syringes without compromising drug stability or activity. In addition to improving safety and time spent per patient, compounding of anti-VEGF biologics enables single-dose vials to be split into multiple syringes, thereby considerably reducing waste and drug expenses. However, symptomatic silicone oil droplets may deposit in the eye’s vitreous body after repetitive injections. To fully avoid this complication, we here report on a novel pharmaceutical compounding method using silicone oil-free syringes and a 33 G × 9 mm Low Dead Space Needle hub injection needle. We evaluate the method for three anti-VEGF biologics commonly used in ophthalmology: aflibercept, ranibizumab (Lucentis) and bevacizumab (Avastin). Our results show that compounding and storage for one week does not compromise the functional activity of the biologics and allows for safe and cost-effective compounding of anti-VEGF biologics for intravitreal injections in prefilled silicone oil-free syringes.

Prevalence of silicone oil droplets in eyes treated with intravitreal injection

Objective

To assess the number of eyes with silicone oil in the vitreous after intravitreal injection.

Methods

This cross-sectional, comparative study was divided into 2 groups: (1) treatment—eyes subjected to antiangiogenic therapy; (2) control—no history of intravitreal injection. Subjects were assessed regarding age, gender, clinical diagnosis, lens status, visual acuity and number of previous intravitreal injections. All eyes underwent a meticulous slit-lamp and ultrasound examination for the identification of silicone oil. ImageJ software was used to quantify the index of silicone oil (IOS) by ultrasonography.

Results

Sixty-seven eyes (30 controls, 37 treated) were included. Slit-lamp examination found silicone oil droplets in 25 out of 37 (67.57%) treated eyes and in none of the control group. Ultrasonography identified silicone oil in 28 out of 37 (75.68%) treated eyes and in 1 out of 30 (3.33%) controls. An observed agreement of 85.07% and a Cohen’s Kappa coefficient of 69.10% (p < 0.0001) between ultrasonography and biomicroscopy were found. Wilcoxon test showed a statistically significant difference (p = 0.0006) in IOS between controls (0.41 ± 0.43%) and treated eyes (2.69 ± 2.55%). Spearman’s correlation test (0.61; p < 0.0001) showed that the greater the number of injections, the higher the IOS.

Conclusions

Silicone oil droplets were found in the majority of the eyes previously treated with antiangiogenic intravitreal injection. The greater the number of injections, the higher the likelihood of finding silicone oil. An improvement in the technique of injection and better-quality syringes post-injection silicone oil droplets.

Shape Characterization of Subvisible Particles Using Dynamic Imaging Analysis

Protein aggregates and subvisible particles (SbvP), inherently present in all marketed protein drug products, have received increasing attention by health authorities. Dynamic imaging analysis was introduced to visualize SbvP and facilitate understanding of their origin. The educational United States Pharmacopeia chapter <1787> emphasizes that dynamic imaging analysis could be used for morphology measurements in the size range of 4-100 μm. However, adequate morphology characterization, as suggested in the United States Pharmacopeia <1787> proposed size range, remains challenging as nonspherical size standards are not commercially available. In this study, a homogenous and well-defined nonspherical particle standard was fabricated and used to investigate the capabilities of 2 dynamic imaging analysis systems (microflow imaging (MFI) and FlowCAM) to characterize SbvP shape in the size range of 2-10 μm. The actual aspect ratio of the SbvP was measured by scanning electron microscopy and compared to the results obtained by dynamic imaging analysis. The test procedure was used to assess the accuracy in determining the shape characteristics of the nonspherical particles. In general, dynamic imaging analysis showed decreasing accuracy in morphology characterization for 5 μm and 2 μm particles. The test procedure was also capable to compare and evaluate differences between the 2 dynamic imaging methods. The present study should help to define ranges of operation for dynamic imaging analysis systems.

LARGE SILICONE DROPLETS AFTER INTRAVITREAL BEVACIZUMAB (AVASTIN)

PURPOSE

Despite its off-label status, intravitreal bevacizumab is the most commonly used intraocular anti-vascular endothelial growth factor agent. Regulation of compounding pharmacies has recently increased to make compounded pharmaceuticals safer. Despite these changes, a marked increase in symptomatic, large silicone oil droplets following intravitreal bevacizumab injections was noticed.

METHODS

Retrospective chart review was performed. Within a single private practice, patients who were noted to have large or symptomatic silicone oil bubbles after an intravitreal injection were reviewed.

RESULTS

A recent, dramatic increase in the incidence of large or symptomatic silicone oil droplets was noted, with 23 cases noted in the past 5 months, compared with 1 in the previous decade. Patients frequently noted a circular floater consisting of a dark ring surrounding a bright central area immediately following an injection of intravitreal bevacizumab. All bevacizumab injections were from single-piece insulin syringes. B-scan ultrasonography produced a very characteristic reverberation pattern. No inflammation or visual acuity loss was noted because of the droplets; however, some patients were annoyed enough to consider vitrectomy.

CONCLUSION

Patients should be carefully evaluated for this possibility, and the characteristic symptom of a round floater consisting of a dark ring surrounding a bright center, and the prominent reverberation pattern on B-scan ultrasonography may help increase detection. Changes in consent forms and discussion of this possibility are indicated while investigation into the cause of this increased incidence continues, especially if one is administering bevacizumab via the one-piece insulin syringes commonly used by compound pharmacies.

Release of silicone oil and the off-label use of syringes in ophthalmology

BACKGROUND/AIMS

To assess silicone oil (SO) release by different brands of syringes used for intravitreal injection under different handling conditions.

METHODS

Eight syringes were analysed: from the USA, Terumo 0.5 mL, Becton-Dickinson (BD) Tuberculin 1 mL, BD Luer-lok 1 mL, BD Ultra-Fine 0.3 mL and Exel Insulin 0.3 mL; from Germany, Braun Omnifix-F 1 mL and Braun Injekt-F 1 mL and from Spain, BD Plastipak 1 mL. The impact of air, priming the plunger, agitation by flicking and fluid temperature on SO release were assessed by light microscopy. Fourier transform infrared spectroscopy (FTIR) was performed to identify the molecular compound in each syringe.

RESULTS

Five hundred and sixty syringes were analysed. Terumo 0.5 mL and BD Ultra-Fine 0.3 mL released more SO than all others. BD Luer-lok 1 mL, BD Plastipak and Braun Omnifix-F 1 mL released little SO; BD Tuberculin 1 mL, Exel 0.3 mL and Braun Injekt-F 1 mL released the least SO. Priming the syringe and different temperatures did not significantly affect SO release. Agitation by flicking caused a significantly higher proportion of samples to have SO droplets and an increased number of oil droplets. Air had an additive effect on the release of oil in the agitation groups. FTIR identified polysiloxane in all syringes but Injekt-F.

CONCLUSION

Syringes commonly used for intravitreal injections frequently release SO droplets, especially when agitated by flicking. To avoid unnecessary ocular risks, syringes should not be agitated before intravitreal injection. It is desirable that syringes be manufactured specifically for ophthalmic use.

Silicone oil droplets in repackaged anti–vascular endothelial growth factors for intravitreal injections: In search of the main source of contamination

Introduction:

Repackaging of anti–vascular endothelial growth factors in polypropylene syringes lubricated with silicone oil for intravitreal use is associated with the presence of intravitreal silicone oil droplets. The objective of this study is to assess how the use of silicone-free syringes (for storage and/or administration) would reduce the amount of silicone oil droplets in the product to be administered.

Methods:

Two 16 mL vials of bevacizumab were repackaged at the compounding pharmacy to obtain four sets of product, each consisting of three 1.2 mL tubes of the drug repackaged in different ways. Set A was repackaged according to routine practice, that is, the drug was placed into 1 mL siliconized syringes and 60 µL aliquots were extracted with 0.5 mL insulin siliconized syringes until reaching 1.2 mL. In set B, a 1-mL silicone-free syringe was used, followed by a 0.5 mL siliconized syringe. In set C, only 0.5 mL siliconized syringes were used. In set D, only the 1-mL silicone-free syringe was used. Micro-Flow Imaging technology was used for quantifying silicone oil droplet–like particles below 25 µm.

Results:

Silicone oil droplet–like particles were absent in set D. Set C had the highest average frequency of these particles, which was much lower in sets A and B. Set B had the lowest frequency.

Conclusion:

0.5 mL insulin syringes with staked-in needles used for supplying the product seem to be the main source of silicone oil contamination in repackaged anti–vascular endothelial growth factors. Silicone-free insulin syringes with staked-in needles would be strongly recommended for supplying anti–vascular endothelial growth factor intravitreal injections from compounding pharmacies.

Release of silicone oil droplets from syringes

BACKGROUND

Intravitreal silicone oil droplets have been found in the vitreous. The aim of this study is to compare the rates of silicone oil released by different brands of commonly used syringes for intravitreal injection after agitation by flicking.

METHODS

Three models of two brands of syringes were analyzed for their rates of silicone oil release: Saldanha Rodrigues (SR) 1 mL insulin syringe (SR, Brazil, syringe 1), Becton-Dickinson (BD) Plastipak 1 mL insulin syringe (Brazil, syringe 2), and BD Safety-Glide 1 mL insulin syringe (USA, syringe 3). All syringes were tested under four different conditions: positive control (fluid with addition of silicone oil) without agitation (group 1, n = 5); positive control with agitation (group 2, n = 3); fluid only without agitation (group 3, n = 5); and fluid only with agitation (group 4, n = 5). Masked graders performed all analyses using light microscopy.

RESULTS

All syringes (1, 2, and 3) released silicone oil droplets in the positive control group regardless of the agitation status (groups 1 and 2). When no oil was added and the syringes were not agitated, only syringe 1 released silicone oil droplets (40% of samples). After agitation, syringes 1 and 3 released silicone oil droplets in all samples. Quantitative analysis showed a significantly (P = 0.011; 11.2 ± 2.9 vs. 0.6 ± 0.9, respectively) higher mean number of silicone oil droplets released by syringe 1 after agitation compared to no agitation. Syringe 1 also had significantly (P = 0.002, 11.2 ± 2.9 vs. 0.0 ± 0.0 vs. 2.2 ± 0.8, respectively) more droplets than syringes 2 and 3 after agitation.

CONCLUSIONS

Syringes commonly used for intravitreal injections frequently release silicone oil droplets when agitated by flicking, especially the SR insulin ones. We recommend that they not be agitated at the time of intravitreal injection and that the manufacturers consider producing syringes adapted for intraocular use.

[Late and sustained intraocular pressure elevation related to intravitreal anti-VEGF injections: Cases requiring filtering surgery (French translation of the article)]

We report cases of delayed, sustained elevated intraocular pressure (IOP) associated with repeated intravitreal anti-VEGF injections (IVI), which ultimately resulted in the need for filtering surgery. Two of the three cases demonstrated severe IOP elevation despite maximal medical treatment following unilateral IVI and required urgent filtering surgery. Optic nerve involvement was severe in all three cases. These intravitreal injections were performed for exudative age-related macular degeneration (AMD), and the patients did not show any sign of glaucoma or ocular hypertension prior to the initiation of treatment. Elevated IOP secondary to intravitreal steroids is a well-known side effect, as is immediate transient IOP elevation associated with anti-VEGF injection. Late, sustained IOP elevation after repeated injections of anti-VEGF, described approximately ten years ago, is often underestimated. Its incidence is estimated between 2.1% and 13% according to studies and increases with the number of IVI (cumulative effect). The pathophysiologic process is becoming increasingly understood, and several risk factors for this chronic IOP elevation have been identified. Most often, it is a moderate IOP elevation for which topical monotherapy is sufficient, or sometimes two, three or four medications or even selective laser trabeculoplasty (SLT). However, filtering surgery may rarely be required. Our findings illustrate a little-described phenomenon: a sudden, severe, late IOP elevation in response to anti-VEGF by an "overflow" effect, requiring urgent filtering surgery.