Auto-Injectors, Pens + Pre-filled Syringes Flashcards
Why these devices?
Improved safety
Improved dosing accuracy
Patient compliance
What are the different types?
Vial
Cartridge
Disposable pen
What are the different classifications?
Single use
Disposable = used until empty
Reusable = new drug can be loaded into container
What is a vial?
Closed vessel containing insulin, which is sealed with pressurised seal
What are the positives of a vial?
Can use for multiple patients
Larger size
Good in secondary care/healthcare/nursing home
Can be used to fill insulin pumps
What are the negatives of a vial?
Require syringe to give dose
Measuring dose potentially more difficult as syringe needed
Not all insulins available in a vial
What is a cartridge?
Disposable container of insulin which is inserted into non-disposable pen device
What are the positives of a cartridge?
Used in non-disposable pen = preferrable
Easy to dial up dose
What are the negatives of a cartridge?
May not be preferrable = non-disposable pen
Pen breaks = no alternative to give insulin
Not all insulins available as cartridge
What is a pre-filled pen?
Disposable container of insulin in a pen, which is fully enclosed + disposed of when finished
What are the positives of a pre-filled pen?
Breaks can easily replace
Easy to dial up dose
Can be recycled
What are the negatives of pre-filled pen?
Differences between disposable pens
Not all insulins available in pre-filled pens
What is an insulin pump?
Continuous subcutaneous insulin infusion
What are the positives of an insulin pump?
Mirrors body + natural pancreatic function
Can be used as closed loop with monitoring devices
Only need one type of insulin
Deliver basal + bolus doses
Different types of pumps available for patient need
What are the negatives of an insulin pump?
Requires high level of patient input
Need good dexterity to fill + use
Pump fails = DKA develop fast
Higher risk of DKA
Describe dose of pre-filled syringes
Single dose = fixed
Describe autoinjector design
Self-firing mechanism
What are the considerations of autoinjector?
Needle length - IM/SC
Method of administration - “place + press”/”swing + jab”
Good in an emergency
What is the length for IM?
7/8mm
What is the length for SC?
<6mm
What is an autoinjector?
Self-firing mechanism for delivery of insulin
What are the positives of an autoinjector?
Improved accuracy of dosing
Designed for people with no medical expertise
Good in an emergency
Reduced risk of needle stick injury
Overcomes needle phobia
Reduce healthcare time input
What are the negatives for autoinjectors?
Futuristic = NOT yet used in practice for insulin
What is syringeability?
Force required to inject a given solution at a given rate via a chosen needle length + gauge
What is the standard needle length for SC (insulin)?
4mm
What does a longer needle increase the risk of?
IM injection
Describe siliconization interaction
Barrier between glass + drug formulation
Prevents adsorption to glass surface
Improved drainability
Lubricates syringe barrel
What are the syringe materials?
Glass = excellent barrier properties, inert
Plastic = stability + environmental issues
What are the gold standard container closure?
Elastomeric closures
Why are elastomeric closures good?
Preserve contents
Do not interact with contents
Physical functionality
Leakproof
Safety for end user
