Investigating the effects of surfactants on the size and hydrolytic stability of poly(adipic anhydride) particles

Abstract

The present study investigates the effects of surfactants (<0.01% v/v) on the size and hydrolytic stability of poly(adipic anhydride) (pAA) micro- and nanospheres fabricated using a modified phase inversion technique. Overall, surfactants increased the output yield by roughly 20%. Lecithin produced the greatest reduction in the volumetric particle size (d_vol) compared to particles fabricated with no surfactant (d_vol = 530 ± 300 nm and 2.2 ± 1.1 µm, respectively). In addition, sorbitan monooleate produced spheres with smaller numeric diameters (d_num) than the control but appeared to induce aggregation (d_vol = 7.7 ± 12.5 µm). The d_num and d_vol were not dependent on the hydrophobicity of the surfactant (R² = 0.36 and 0.03, respectively) or the apparent surface tension of the non-solvent (NS) phase (R² = 0.44 and 0.04, respectively). In addition, quantitative DSC and FT-IR analysis confirmed that altering the particle size could also influence the hydrolytic stability of pAA.

Key Words: :

• Polyanhydride
• nanosphere
• SEM
• TEM
• DSC
• FT-IR