Title

RELEASE OF SILICONE OIL FROM SYRINGES AND NEEDLES COMMONLY USED IN OPHTHALMOLOGY

Introduction

Twenty-five million intravitreal injections (IVI) are performed annually worldwide. Silicone oil has been identified in syringes and needles by different techniques. The objective of this study was to quantify the number of oil particles in syringes and in the inner lumen of needles.

Methods

Eight models of syringes (“Unmarketed” oil-free, HSW Normject, HSW Softject, Zero Residual Luer-lock, BD Luer-lok, BD Tuberculin, BD Ultra-Fine, and SR Tuberculin) were analyzed by imaging flow cytometry for the release of silicone oil under agitation by flicking and compared with no agitation. Additionally, eleven models of needles (BD PrecisionGlide 27G and 30G, BD Eclipse 30G, JBP 27G, 30G, 33G, and 34G, TSK 27G, 30G, and 34G, and Zero Residual 30G) were analyzed by imaging flow. Samples were fluorescently labeled using the Amnis Silicone Oil Detection Kit (Luminex Corp, Seattle, WA). All data were collected using an Amnis FlowSight imaging flow cytometer.

Results

One hundred and ninety-two syringes were analyzed. Agitation by flicking caused a statistically significant increase in the number of oil droplets in comparison to no agitation in all syringe groups tested, except for the “Unmarketed” oil-free one. These findings were similar regardless of the drug used. Baseline unagitated groups showed negligible levels of oil (< 40 particles/uL) in all but BD Ultra-Fine (155 particles/uL) and SR Tuberculin (954 particles/uL). Of the 11 needle models evaluated, only one presented a noticeable release of silicone oil – the BD Eclipse 30G. No relationship between needle diameter (gauge) and silicone oil release was observed in any of the studied models.

Discussion

Silicone oil droplets are released by the syringes. Agitation by flicking prior to injection tends to release more silicone oil. This study showed that most of the commercially available ones that are used in ophthalmic procedures do not release silicone oil from its inner surface and the needle diameter does not influence this finding.

Keywords

intravitreal injection; needle; silicone oil; syringe.

Area

CLINICAL CASE

Authors

Gustavo Barreto Melo, Natasha F S Cruz, Lydianne L M Agra, Christine Probst, Luiz H Lima, John Carpenter, Michel Eid Farah, Maurício Maia