Slide 2:
Self-regulated delivery systems are closed-loop controlled devices in which the release is adjusted by the system in response to feedback information without any external intervention. Eg: delivery of insulin in response to glucose level in blood.
pH-sensitive polymers:
The system consists of immobilized glucose oxidase in a pH responsive polymeric hydrogel, enclosing a saturated insulin solution.
Slide 3:
As glucose diffuses into the hydrogel, glucose oxidase catalyzes its conversion to gluconic acid, thereby lowering the pH in the microenvironment of the membrane and causing swelling.
Insulin is diffused through these pores in relation to this pH change.
Implantable Mechanochemical Pump: :
Implantable Mechanochemical Pump: The device consists of three chambers:
Chamber I : contains insulin solution.
Chamber II: aqueous fluid.
Chamber III : pH- sensitive polymer with glucose oxidase that expands when glucose level rises.( this is the deriving force of the pump)
Slide 7:
Glucose sensetive Swellable hydrogel Insulin formulation Agueous medi Valve oriffice Blood glucose normal
Slide 8:
Blood glucose up
Competitive binding :
Competitive binding Based on competitive binding between glucose and glycoselated insulin on specific sitde of concavavalineA.
Glucose + glycoselated insulin-Con A
glucose-ConA + glycoselated insulin
insulin
Slide 10:
Glucose in Insulin out G Competitive binding Insulin pump
Urea responsive systems :
Urea responsive systems Urea NH4HCO3 +NH4OH
pH increase ionization of a polymer
polymer erosion Urease