Dynamic changes in size distribution of emulsion droplets during ethyl acetate-based microencapsulation process

Area of Science:

• Materials Science
• Chemical Engineering
• Pharmaceutical Technology

Background:

• Microsphere production relies on controlled emulsification for desired particle size.
• Poly(lactide-co-glycolide) (PLGA) microspheres are widely used in drug delivery.
• Emulsification time is a critical parameter influencing droplet and subsequent microsphere characteristics.

Purpose of the Study:

• To investigate the dynamic effect of emulsification time on emulsion droplet size.
• To quantify the relationship between emulsification duration and microsphere size distribution.
• To understand the impact of emulsification kinetics on PLGA microsphere formation.

Main Methods:

• Emulsification of a poly(lactide-co-glycolide) and ethyl acetate solution in poly(vinyl alcohol).
• Varied emulsification times from 2 to 60 minutes.
• Ethyl acetate extraction followed by microsphere size distribution analysis.

Main Results:

• Emulsification time extended from 2 to 60 minutes reduced droplet size from 98.1 to 50.3 microm.
• Droplet surface area increased from 0.07 to 0.29 m²/g with prolonged emulsification.
• Smaller droplets (1-60 microm) increased, while larger ones (>81 microm) disappeared, indicating fragmentation.

Conclusions:

• Prolonging emulsification time leads to smaller emulsion droplets and increased microsphere surface area.
• Droplet fragmentation during emulsification is the primary driver for smaller microsphere populations.
• The timing of solvent extraction influences droplet dynamics and final microsphere size distribution.