Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2000 Mar 23;1(1):E5.
doi: 10.1208/pt010105.

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

Y Bahl  1 , H Sah
Affiliations

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

Y Bahl et al. AAPS PharmSciTech. .

Abstract

This study investigated the dynamic effect of the emulsification process on emulsion droplet size in manufacturing microspheres using ethyl acetate as an organic solvent. A dispersed phase consisting of poly(lactide-co-glycolide) and ethyl acetate was emulsified in a poly(vinyl alcohol) aqueous solution for a predetermined time ranging from 2 to 9, 16, 23, 30, 40, 50, or 60 minutes. Ethyl acetate was then quickly extracted to transform emulsion droplets into solidified microspheres, and their size distribution was determined. This experimental design allowed quantification of the size distribution of emulsion droplets over the course of emulsification. When emulsification time was extended from 2 to 60 minutes, the emulsion droplets decreased in size from 98.1 to 50.3 microm and their surface area increased from 0.07 to 0.29 m2/g. Overall, prolonging emulsification time up to 60 minutes resulted in the progressive evolution of smaller emulsion droplets (1-60 microm) and the simultaneous disappearance of larger ones (> 81 microm). Increases in the total number of microspheres and their surface area were caused mainly by continuous fragmentation of emulsion droplets before ethyl acetate extraction. The increase in the smaller microsphere population might also be due in part to shrinkage of microspheres. These results show that the onset of ethyl acetate extraction influenced the kinetics of the breakup and formation of emulsion droplets, thereby affecting to a great extent the size distribution of microspheres.

PubMed Disclaimer

References

    1. Benoit JP, Marchais H, Rolland H, Velde VV. Biodegradable microspheres: advances in production technology. In: Benita S, editor. Microencapsulation: Methods and Industrial Applications. New York, NY: Marcel Dekker Inc; 1996. pp. 35–72.
    1. Thies C. Formation of degradable drug-loaded microparticles by in-liquid drying method. In: Donbrow M, editor. Microcapsules and Nanoparticles in Medicine and Pharmacy. Boca Raton, FL: CRC Press; 1992. pp. 47–71.
    1. Sánchez A, Vila-Jata JL, Alonso MJ. Development of biodegradable microspheres and nanospheres for the controlled release of cyclosporin A. Int J Pharm. 1993;99:263–273. doi: 10.1016/0378-5173(93)90369-Q. - DOI
    1. Poncelet De Smet B, Neufeld RJ. Control of mean diameter and size distribution during formulation of microcapsules with cellulose nitrate membranes. Enzyme Microb Technol. 1989;11:29–37. doi: 10.1016/0141-0229(89)90110-5. - DOI
    1. Jeyanthi R, Mehta RC, Thanoo BC, DeLuca PP. Effect of processing parameters on the properties of peptide-containing PLGA microspheres. J Microencapsulation. 1997;14:163–174. doi: 10.3109/02652049709015330. - DOI - PubMed

Publication types

LinkOut - more resources