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

[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.

Stability of ranibizumab during continuous delivery from the Port Delivery Platform

The Port Delivery System with ranibizumab (PDS) is an innovative intraocular drug delivery system that has the potential to reduce treatment burden in patients with retinovascular diseases. The Port Delivery Platform (PD-P) implant is a permanent, indwelling device that can be refilled in situ through a self-sealing septum and is designed to continuously deliver ranibizumab by passive diffusion through a porous titanium release control element. We present results for the studies carried out to characterize the stability of ranibizumab for use with the PD-P. Simulated administration, in vitro release studies, and modeling studies were performed to evaluate the compatibility of ranibizumab with the PD-P administration components, and degradation and photostability in the implant. Simulated administration studies demonstrated that ranibizumab was highly compatible with the PD-P administration components (initial fill and refill needles) and commercially available administration components (syringe, transfer needle, syringe closure). Subsequent simulated in vitro release studies examining continuous delivery for up to 12 months in phosphate buffered saline, a surrogate for human vitreous, showed that the primary degradation products of ranibizumab were acidic variants. The presence of these variants increased over time and potency remained high. The stability attributes of ranibizumab were consistent across multiple implant refill-exchanges. Despite some degradation within the implant, the absolute mass of variants released daily from the implant was low due to the continuous release mechanism of the implant. Simulated light exposure within the implant resulted in small increases in the relative amount of ranibizumab degradants compared with those seen over 6 months.

Anti-complement drugs for the treatment of geographic atrophy and the release of silicone oil

Intravitreal injections are a common procedure in ophthalmology, often using syringes coated with silicone to aid piston movement and needles coated with silicone oil to facilitate penetration of the sclera. Pegcetacoplan and avacincaptad pegol, recently approved for clinical use by the US Food and Drug Administration, have higher viscosity and seem more susceptible to entrap air bubbles compared to anti-VEGF drugs.It is plausible that both anti-complement drugs could be associated with a higher likelihood of introducing silicone oil in the vitreous because of higher viscosity, with potentially higher friction at the inner surface of syringe barrel, in the vicinity of silicone oil. In addition to this, undesirable agitation might be inadvertently promoted by some retina specialists to remove air bubbles from the drug solution.In conclusion, recent reports of silicone oil droplets in the vitreous of patients receiving pegcetacoplan injection might be related to both its viscosity and to agitation of the syringe to remove air bubbles. Since avacincaptad pegol also is viscous, though with different pH, syringe and filter needle, we might expect similar reports for this agent soon. We also recommend further studies be carried not only to clarify the current matter but also the potential association between the combination of agitation, silicone oil and inflammation or any immune response.

Effects of Processing-Induced Contamination on Organic Electronic Devices

Organic semiconductors are a family of pi-conjugated compounds used in many applications, such as displays, bioelectronics, and thermoelectrics. However, their susceptibility to processing-induced contamination is not well understood. Here, it is shown that many organic electronic devices reported so far may have been unintentionally contaminated, thus affecting their performance, water uptake, and thin film properties. Nuclear magnetic resonance spectroscopy is used to detect and quantify contaminants originating from the glovebox atmosphere and common laboratory consumables used during device fabrication. Importantly, this in-depth understanding of the sources of contamination allows the establishment of clean fabrication protocols, and the fabrication of organic field effect transistors (OFETs) with improved performance and stability. This study highlights the role of unintentional contaminants in organic electronic devices, and demonstrates that certain stringent processing conditions need to be met to avoid scientific misinterpretation, ensure device reproducibility, and facilitate performance stability. The experimental procedures and conditions used herein are typical of those used by many groups in the field of solution-processed organic semiconductors. Therefore, the insights gained into the effects of contamination are likely to be broadly applicable to studies, not just of OFETs, but also of other devices based on these materials.

Application of Formulation Principles to Stability Issues Encountered During Processing, Manufacturing, and Storage of Drug Substance and Drug Product Protein Therapeutics

The field of formulation and stabilization of protein therapeutics has become rather extensive. However, most of the focus has been on stabilization of the final drug product. Yet, proteins experience stress and degradation through the manufacturing process, starting with fermentaition. This review describes how formulation principles can be applied to stabilize biopharmaceutical proteins during bioprocessing and manufacturing, considering each unit operation involved in prepration of the drug substance. In addition, the impact of the container on stabilty is discussed as well.

Prevalence and implications of the presence of intraocular silicone oil droplets in patients treated with intravitreal injections of anti-VEGF

Background

To determine the percentage of patients who have silicone droplets in the vitreous after treatment with different anti-Vascular Endothelial Growth Factor (anti-VEGF) intravitreal injections (IVI) and how symptomatic they are.

Methods

One hundred fifty-two eyes of 140 patients who had at least received an IVI were recruited for this study. Data collection included the number and type of IVI (aflibercept, ranibizumab and bevacizumab) and the follow-up time. A complete ophthalmologic examination was carried out and patients were classified in four groups according to the amount of silicone droplets found in dilated fundoscopy (nonexistent, scarce, moderate and abundant). Measurement of intraocular pressure (IOP) was also carried out. An interview was conducted to report the presence and intensity of the symptomatology.

Results

Silicone oil droplets were reported in 109 eyes (71.7%). A positive correlation was found between the number of IVIs received and the quantity of droplets found, especially when aflibercept was used. Posterior vitreous detachment (PVD) was present in 65.8% of the patients, showing a positive correlation with the number of bubbles. Regarding the symptomatology, 60 eyes (39.5%) had floaters and the disturbance was reported to be 4 out of 10. The group with a moderate amount of silicone droplets had the highest percentage of floaters (60%). No statistical differences in the IOP were found between groups, although the group with abundant droplets had a higher mean IOP.

Conclusion

A high prevalence of silicone droplets in vitreous of patients who undergo IVI treatment was found. It appears to have little impact on symptomatology and rise of IOP.