Controlled drug release by polymer dissolution. II: Enzyme-mediated delivery device.

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Drug Delivery Systems

Background:

• Controlled drug release is crucial for effective therapeutic outcomes.
• Bioerodible polymers offer potential for tunable drug delivery profiles.
• External stimuli-responsive systems enhance control over drug release kinetics.

Purpose of the Study:

• To develop a novel, closed-loop drug delivery system.
• To control hydrocortisone release from a bioerodible polymer using an external compound.
• To investigate the effect of urea on polymer erosion and drug release rates.

Main Methods:

• Hydrocortisone was incorporated into a methyl vinyl ether-maleic anhydride copolymer.
• Polymer-drug mixture fabricated into disks and coated with a urease-immobilized hydrogel.
• Drug release studied in the presence and absence of external urea at constant pH.

Main Results:

• In the absence of urea, hydrocortisone release followed normal polymer erosion kinetics.
• Addition of urea generated ammonium bicarbonate and ammonium hydroxide, accelerating polymer erosion and drug release.
• The increase in drug release rate was proportional to urea concentration and was reversible upon urea removal.

Conclusions:

• A novel closed-loop drug delivery system responsive to external urea was successfully developed.
• Urea-induced changes in hydrogel microenvironment accelerate polymer erosion and drug release.
• The system demonstrates tunable and reversible control over drug delivery, offering potential for advanced therapeutics.