Biodegradable microbeads with enhanced particle size distributions

Biodegradable microparticles comprising a mixed cellulose ester, wherein the biodegradable microparticles exhibit at least 40 percent biodegradability at 60 days according to at least one of the OECD 301B, OECD 301C, or OECD 301F test methods,

• wherein the biodegradable microparticles exhibit a monomodal particle size distribution with a span in the range of 1.0 to 3.0,
• wherein the mixed cellulose ester comprises—
• (a) an average degree of substitution for acetyl substituents (“DSAc”) in the range of 0.1 to 2.3,
• (b) an average degree of substitution for propionyl substituents (“DSPr”) or an average degree of substitution for butyryl substituents (“DSBu”) in the range of 0.1 to 1.5, and
• (c) an average degree of substitution for hydroxyl substituents (“DSOH”) in the range of 0.6 to 2.8.