Formation and characterization of pH-responsive liquid core microcapsules.

Area of Science:

• Materials Science
• Chemical Engineering
• Drug Delivery

Background:

• Microencapsulation is crucial for protecting active ingredients and enabling controlled release.
• Developing versatile protocols for microcapsule fabrication with tunable release mechanisms is an ongoing challenge.

Purpose of the Study:

• To establish a robust protocol for creating microcapsules with diverse core and shell compositions.
• To investigate the impact of shell integrity on release profiles.
• To evaluate pH-triggered release as a targeted delivery strategy.

Main Methods:

• A generalized protocol for microcapsule fabrication using various polymers (e.g., poly(4-vinylpyridine), poly(lactide-co-glycolide)) was developed.
• Release kinetics were studied under different conditions, including complete and incomplete shell formation.
• pH-triggered release was assessed by monitoring the release of methylene blue dye.

Main Results:

• Both poly(4-vinylpyridine) and poly(lactide-co-glycolide) microcapsules exhibited triggered release below pH 3.5.
• Poly(4-vinylpyridine) shells swelled at low pH, while poly(lactide-co-glycolide) shells degraded via ester bond cleavage.
• Complete release of encapsulated substances was achieved within 6 hours for both polymer types.
• The protocol successfully encapsulated various active ingredients, including polyacrylamide and hydroxypropylcellulose.

Conclusions:

• The established protocol offers a versatile method for microencapsulation with tunable release properties.
• pH-triggered release mechanisms were successfully demonstrated for targeted delivery applications.
• The findings support the potential of these microcapsules for encapsulating diverse active ingredients.