Advanced insulin delivery

Problems with conventional insulin delivery

• inconvenience

• needle phobia

• patient compliance and inaccurate dosing

• hypoglycaemia risk

• postprandial glucose control

• injection pain

• lipodystrophy

stimuli responsive insulin delivery

• we want a device which can automatically detect changes in blood glucose and then release insulin

• detector

• trigger

• release

detector

• measures glucose concentration in blood

trigger

• causes a chemical or physical change in drug delivery system

release

• switches on release of insulin

stimuli responsive insulin delivery approaches

• insulin polymer gels

• gel sol transition

insulin polymer gels

• the enzyme glucose oxidase is included in the polymer formulation

gel sol transition

• these polymer approaches are theoretically sound but in practice have not yet been successful

• any local pH changes i.e those not caused by glycolic acid production, would also lead to insulin release

• Build up of H2O2 needs to be addressed

• other smart approaches have proven more successful

insulin pumps

• portable programmable devices that deliver insulin directly into the body continually without the patient needing to inject themself

• subcutaneous needle or cannula delivers the insulin under the skin at the chosen site continuous subcutaneous insulin infusion

• constant release of basal insulin plus bolus doses at mealtime

• pumps can be broken down into two categories

  • tethered pump

  • patch pump

tethered insulin pumps

• battery powered device containing the insulin reservoir, pumping mechanism, control buttons and/or screen to program insulin delivery

• tubing

  • flexible plastic tube connects the insulin reservoir to an infusion set

• infusion set

infusion set

• the infusion set attaches to the skin with an adhesive patch. the set contains a needle/ cannula that delivers insulin subcutaneously. often used around the abdomen but can be placed on the upper arm, thighs etc.

patch pumps

• most commonly available patch pump in the uk is the insult omnipod dash

• patient manually fills a new pod with insulin using a syringe

• pod can be placed at most sites around the body where you would normally inject insulin

• cannula insert semi automatically once pod has been attached to the skin

• wirelessly connects to a personal diabetes manager or smartphone

• IPX8 waterproof rating for the pod

What if a pump malfunction

• signs of pump malfunction:

  • high blood glucose symptoms

  • ketones in urine or blood

• stop the pump and administer correction dose from backup pen

• look for air bubbles, change cannula/ infusion set/ tubing

• continue with insulin from pen if device changes do not resolve issue

• check glucose/ ketones regularly every 1-2 hours do not go to bed until levels have returned to normal

• contact healthcare professional and/ or pump manufacturer

continuous glucose monitoring

• traditionally patient have monitored their BG levels by finger prick methods

• requires: meter + test strips +finger prick device + lancet

• some patient averse to regular finger prick testing and their BG levels can fluctuate considerably between test

• CGM is an alternative to finger prick testing

  • real time

  • intermittently scanned or flash

• disposable sensor with 0.4 mm filament is inserted 5mm under the skin

• newer techniques and devices are a big improvement on the glucoWatcb

contionous glucose monitoring IsCGM

• BG levels only show when you scan the sensor

• sensor location: back of upper arm

• not originally used alongside insulin pumps

• 4 year old and above

rtCGM

• BG level continuously updated on smartphone/ device

• more compatible with insulin pumps

• sensor location: more options

• 2 years old and above

hybrid closed loop system

• Closed loop systems/ hybrid closed systems/ artificial pancreas

• replaces the open loop system

• not a fully closed system hence the term ‘hybrid’

  • patient needs to have some input

• variety of different hybrid systems

zoe

• a personalised nutrition programme which uses freestyle fibre device

• lifestyle programme which works with a freestyle fibre 2 device

• not NHS funded

• BG monitoring + one off blood lipid test + gut health test

• showing promise as an approach for the public to learn more about what they eat and its effect on them