FEEDBACK-REGULATED DRUG DELIVERY SYSTEMS

1. FEEDBACK-REGULATED DRUG DELIVERY SYSTEMS (FRDDS)
PRESENTED BY :
Elahe Tolideh
1st M.PHARM
Dept of Pharmaceutics
Al Ameen college of pharmacy
Bangalore
SUBMITTED TO :
Dr. Preeti Karwa
HOD Dept of Pharmaceutics
Al Ameen college of pharmacy
Bangalore
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2. Controlled Release Drug Delivery Systems
Release therapeutic agents at predetermined
rates, durations, and target sites to achieve
optimal therapeutic outcomes.
(1) Rate programmed drug delivery system
(2) Activated modulated drug delivery
system
(3) Feedback regulated drug delivery system
(4) Site targeting drug delivery system
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3. Feedback Regulated Drug Delivery System
➢ Release of drug molecules from the delivery
systems is activated by a triggering agent, such as
a biochemical substance, in the body in real time
and also regulated by its concentration via some
feedback mechanisms.
➢ The rate of drug release is then controlled by the
concentration of triggering agent detected by a sensor
in the feedback-regulated mechanism.
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4. Basic Structure
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5. Classification
➢ A. Bioerosion-Regulated Drug Delivery System
➢ B. Bioresponsive Drug Delivery Systems
➢ C. Self-Regulating Drug Delivery Systems
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6. Bioerosion-Regulated Drug Delivery System
➢ Drug-dispersed bioerodible matrix made
from PVME-HE.
➢ Protective Coating: The matrix was
coated with a layer of immobilized urease.
➢ Example: Hydrocortisone
○ In neutral pH, the polymer erodes very slowly.
○ In the presence of urea, the urease enzyme breaks down urea into ammonia.
○ The ammonia raises the pH, causing the polymer matrix to degrade rapidly.
○ This results in the release of drug molecules.
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8. Bioresponsive Drug Delivery Systems
➢ Developed by Horbett.
➢ The drug reservoir is enclosed in a
bioresponsive polymeric membrane
➢ The permeability of the membrane is
controlled by the concentration of a
biochemical agent in the surrounding
tissue.
➢ Example: Glucose-Triggered Insulin
Delivery System
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9. Smart Hydrogel Wrapp:
Insulin is stored inside a hydrogel membrane that
controls its release.
Glucose Sensor:
The membrane contains glucose oxidase, which
detects glucose levels.
Triggered Release:
When glucose enters, it converts into gluconic acid,
causing the membrane to swell and open, releasing
insulin.
Self-Regulating:
The system automatically adjusts insulin release
based on glucose levels, mimicking the body's
natural response.
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10. Glucose-Responsive Insulin Delivery Systems Using Nanocarriers
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11. Self-Regulating Drug Delivery Systems
➢ Works based on a reversible and competitive binding process to control drug release.
➢ The drug is stored inside a semipermeable polymeric membrane as a drug complex.
➢ A biochemical agent (e.g., glucose) from the body
triggers drug release by diffusing into the membrane.
➢ Example: Insulin delivery system
using a lectin-based
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12. ➢ Insulin delivery system using a lectin-based reversible binding mechanism.
➢ Insulin is bound to sugar molecules (e.g., maltose) to form an insulin-sugar-lectin
complex.
➢ The complex is encapsulated in a semipermeable membrane.
➢ When glucose enters, it competes for binding sites on lectin, causing insulin to be
released.
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13. FRDDS In Maintaining Blood Glucose Levels In Pancreatectomized Dogs
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14. Disadvantage:
➢ Non-linear insulin release: The system does not proportionally adjust insulin release
to glucose levels.
Example: A glucose level of 500 mg/dl triggers insulin release at only twice the rate
of that at 50 mg/dl, instead of a significantly higher rate.
➢ Complex formulation: The development process relies on glycosylated insulin-
Concanavalin A complex, which is encapsulated inside a polymer membrane, making
the system more intricate.
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15. Morphine Overdose
Mechanism of Action
● Morphine overdose causes
respiratory depression, increasing
CO₂ levels in the blood.
● The CO reacts with water
₂ , forming
bicarbonate (HCO ) and H ions
₃⁻ ⁺ ,
lowering pH.
● This triggers the drug carrier to
release naloxone, reversing
morphine’s effects.
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16. Polyurethane
Polymeric material composed of organic units drug delivery systems, due to its biocompatibility,
flexibility, and durability.
Roles in FRDDS:
➢ pH-Responsive Release – PU hydrogels alter swelling behavior based on pH, useful for targeted
drug delivery in the GI tract and tumor therapy.
➢ Enzyme-Triggered Release – PU degrades in the presence of specific enzymes, allowing
localized and self-regulated drug release in diseased tissues.
➢ Temperature-Sensitive PU – Releases drugs at specific body temperatures, beneficial for fever-
triggered therapies.
➢ PU Nanoparticles – Enables controlled and sustained drug release, modifiable for external
stimuli like magnetic fields or ultrasound.
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17. Recent advances in glucose-responsive insulin delivery systems: novel hydrogels and future applications
➢ Glucose-Responsive Insulin Delivery Systems (GRIDS): These systems aim to mimic the body's
natural insulin regulation by releasing insulin in response to elevated blood glucose levels, thereby
reducing the need for frequent blood sugar monitoring and manual insulin injections.
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18. References
https://pmc.ncbi.nlm.nih.gov/articles/PMC9438743/
https://www.mdpi.com/2218-273X/12/9/1198
Novel Drug Delivery Systems, Yie W Chien
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