Preparation of microspheres and microcapsules by interfacial polycondensation techniques

Area of Science:

• Polymer Chemistry
• Materials Science
• Chemical Engineering

Background:

• Microspheres and microcapsules are versatile materials with applications in drug delivery, encapsulation, and diagnostics.
• Interfacial polycondensation is a key method for synthesizing these microparticles.
• Understanding the formation mechanisms is crucial for controlling particle morphology and properties.

Purpose of the Study:

• To provide a comprehensive methodological review of microsphere/microcapsule production via interfacial polycondensation.
• To elucidate the mechanisms governing particle and capsule formation.
• To differentiate between particle-forming and capsule-forming interfacial polycondensation.

Main Methods:

• Review of established procedures for interfacial polycondensation.
• Analysis of monomer partitioning in two-phase suspension systems.
• Discussion of polymer solubility in the droplet phase and its impact on morphology.

Main Results:

• Interfacial polycondensation involves reacting complementary monomers in immiscible phases.
• Particle formation occurs when the polymer is soluble in the droplet phase.
• Capsule formation results from an insoluble polymer forming a membrane around droplets.

Conclusions:

• The solubility of the polycondensate in the droplet phase dictates whether microspheres or microcapsules are formed.
• Particle-forming interfacial polycondensation, e.g., polycarbonate resins, yields monolithic particles.
• Capsule-forming interfacial polycondensation, e.g., nylon microcapsules, creates reservoir structures for encapsulating active substances.