Enzymatically activated microencapsulated liposomes can provide pulsatile drug release.

Area of Science:

• Biomedical Engineering
• Materials Science
• Drug Delivery Systems

Background:

• Controlled release systems are crucial for effective drug delivery.
• Liposomes offer a versatile platform for encapsulating active substances.
• Achieving pulsatile release patterns remains a challenge in drug delivery.

Purpose of the Study:

• To develop a system for delayed or pulsed release of biologically active substances.
• To enhance the stability of encapsulated active substances.
• To control the release kinetics of encapsulated substances.

Main Methods:

• Encapsulating liposomes containing active substances within microcapsules.
• Coating liposomes with phospholipase A2 to induce pulsatile release.
• Utilizing poly(L-lysine) for microcapsule coating and controlling release rates.
• Assessing the stability of a model enzyme (horseradish peroxidase) at 37°C.

Main Results:

• A system for delayed and pulsed release of active substances was successfully developed.
• Pulsatile release was achieved both in vitro and in vivo.
• Release onset time and rate were controllable via phospholipase A2 amount, poly(L-lysine) molecular weight, and liposome composition.
• The system protected a model enzyme from degradation at 37°C, retaining 40% activity after 30 days.

Conclusions:

• Microencapsulated liposomes provide a robust platform for controlled and pulsed drug delivery.
• The developed system offers tunable release kinetics and enhanced stability for active substances.
• This approach has significant potential for improving therapeutic outcomes through advanced drug delivery.