What is syringe plunger stopper piston?

What is a syringe?

A syringe is a device used for injection, irrigation or feeding. A 3-part disposable syringe usually includes: barrel, plunger, stopper, hub and hypodermic needle.

What are types of syringe?

Syringes can be divided into several types based on different standards.

Based on Shape

There are luer lock syringe, luer slip centric syringe, luer slip eccentric syringe.

• Luer Lock Syringe: allowing needle to be twisted into tip and locked in place to ensure needle not be removed accidentally.
• Luer Slip Centric Syringe: barrel head is at centre part.
• Luer Slip Eccentric Syringe: barrel head is at side part, used for puncturing vein or artery.

Based on Application

• common disposable syringe
• prefilled syringe
• oral syringe
• dental syringe
• low-resistence syringe
• high pressure syringe

Different types will have different standards for plunger stopper piston of material and performance.

What is syringe plunger stopper piston?

Syringe plunger stopper is essencial part for 3-part syringe. It mainly works for ensuringe basic but important performance: sealing performance and sliding performance.

Material for syringe plunger stopper usually includes:

• latex rubber——lower cost, but contains latex which may cause allergy
• isoprene rubber——no latex, no allergy
• silicone rubber——no latex, better performance to replace isoprene rubber
• butyl rubber——used for prefilled syringe to ensure no chemical reaction with medication
• TPE & PVC——injection mouled products, easy and convenient, but not good in sealing performance, this type of material will probablay cause leakage

Among all rubber materials, the most common type for disposable syringe is isoprene rubber, and most common type for prefilled syringe is butyl rubber.(What are different materials for syringe plunger stopper? Click here to know more details.)

How to select a suitable syringe plunger stopper piston?

1. Material should be decided first to ensure basic quality requirement for certain type of syringe, like isoprene rubber for common disposable syringe, or butyl rubber gasket for prefilled syringe(PFS).
2. Performance should be tested as per quality standard.

What is basic performance of syringe plunger stopper? Taking disposable syringe plunger stopper as an example.

Physical Performance

• Dead Space: shall be minimized to reduce waste and transmission of infectious agents. This performance mainly depends on cooperation bewteen plunger stopper head and barrel end.
• Leakage: shall be no air or liquid leakage pass the plunger stopper or sealing circle.
• Force to operate stopper: shall have suitable force to push and pull plunger based on different sizes and volumes of  syringe.

Chemical Performance

• PH Value: not more than 1.0
• Extractable Metal Content: total content of lead,  tin, zinc and iron shall be not more than 5mg/L
• Reducing Substances: shall be no more than 0.4 ml
• UV Absorbance: shall be not more than 0.2

Biological Performance

• Pyrogen reaction: no
• Cytotoxic: no
• Hemolysis: no
• Skin Reaction: no
• Allergic Reaction: no
• Acute Systemic Toxicity: no