FEEDBACK REGULATED DRUG DELIVERY SYSTEMS

1. FEEDBACK REGULATED
DRUG DELIVERY
SYSTEMS
PRESENTED BY:
MASUM AHMED
M.PHARM1ST SEM
DEPT. OF PHARMACEUTICS
SUBMITTED TO:
DR. D. MOHANTY,
ASSOCIATE PROFESSOR
DEPT. OF PHARMACEUTICS

2. CONTENTS
• Introduction
• Classification
• Bio-Erosion Regulated System
• Bio-Responsive Regulated System
• Self-Regulating Drug Delivery Systems
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3. INTRODUCTION
• In this type of Controlled Release Drug Delivery System, a physiological response
activates the release of drugs from the carrier.
•A triggering agent activates the process of release of the drug, such as a
biochemical substance, in the body via some feedback mechanisms.
•The rate of drug release is synchronized by the concentration of a triggering agent
that is detected by a sensor used in the feedback-regulated drug delivery system.
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Fig: Feedback regulated drug delivery system

5. CLASSIFICATION
a) Bio-Erosion Regulated System
b) Bio-Responsive Regulated System
c) Self-Regulating Drug Delivery Systems
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6. Bio-Erosion Regulated System
• This system was developed by Heller & Trescony by applying the concept of
FDDS.
• In this, the system consist of drug dispersed bioerodible matrix fabricated from
half ester such as poly vinyl methyl ether which is coated with immobilised
urease.
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• In a solution with close to neutral pH, the polymer polyvinyl methyl ether
erodes very slowly but in the presence of urea, urease forms ammonia at the
surface of drug and metabolize the urea.
• The cause of the change of pH increases the rapid degradation of polymer
matrix and release of drug molecules.

8. BIO-RESPONSIVE REGULATED SYSTEM
• Developed by Horbett as applied feedback regulated drug delivery system.
• In this, the drug reservoir is enclosed in the bio-responsive polymeric
membrane and permeability of drug molecule is controlled by concentration of
biochemical agents in tissue where the system is located.
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EXAMPLE: GLUCOSE TRIGGERED INSULIN DELIVERY SYSTEM
• In this delivery system, insulin reservoir is covered by
the hydrogel membrane which contain NR2 (amide
group) group.
• In alkaline solution, NR2 group is fixed, and the
membrane is unswollen and impermeable to insulin.
• As glucose entered into the membrane, oxidized inside
the membrane and forms gluconic acid.
• This process triggered the protonation of NR2 into
N+R2H and hydrogel layer become swollen and thus
permeable to insulin molecule.
• The amount of insulin delivered is bio-responsive to
the concentration of the glucose penetrating into the
system.

10. SELF-REGULATING DRUG DELIVERY
SYSTEMS
• This mechanism is regulated by the reversible and competitive binding
mechanism for the activation and release of drugs.
• In this, drug reservoir encapsulated within a polymeric semipermeable
membrane.
• The release of the drug is activated by the biochemical agent of the tissue.
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EXAMPLE: SELF REGULATING INSULIN DELIVERY SYSTEM
• It first involve preparation of biologically active insulin derivatives in which insulin
is coupled with sugar component & this into insulin-sugar-lectin complex, which is
then encapsulated in semipermeable membrane.
• As blood glucose diffuse into device & bind at sugar binding sites in lectin
molecules, it activate release of insulin-sugar derivatives.
• This derivatives then diffuse out of device, and the whole amount of release is
depend on glucose concentration. Thus self regulating drug delivery is achieved.

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Fig: Self Regulated Insulin Delivery System

13. THANK YOU!
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