Direct Comparison of Analogous Amphiphilic Gradient and Block Polyoxazolines
Lenka Loukotová, Pavel Švec, Ondřej Groborz, Tomáš Heizer, Hynek Beneš, Helena Raabová, Tereza Bělinová, Vı́t Herynek, Martin Hrubý
Abstract
Both gradient and block copolymers can be used as drug delivery systems, but their relative (dis)advantages remain unknown. Thus, we directly compared analogous amphiphilic gradient and block polyoxazolines for their physicochemical properties and potential as building components of nanodrugs. For this purpose, we prepared a library of 18 polymers with varying ratios of monomeric units, using 2-methyl-2-oxazoline (MeOx) as a hydrophilic monomer and 2-phenyl-2-oxazoline (PhOx), 2-(4-butylphenyl)-2-oxazoline (BuPhOx), or 2-(4-butoxyphenyl)-2-oxazoline (BuOPhOx) as a hydrophobic monomer, and determined their homo/heteropolymerization kinetics. Our results showed that gradient copolymers had broader glass transition intervals and formed nanoparticles several times smaller and more compact than the corresponding block analogs. In particular, PMeOx70-grad-PhOx30 and PMeOx70-grad-BuPhOx30 exhibited a significantly higher drug loading capacity and entrapment efficiency than their corresponding block analogs. Notwithstanding these differences, all polymers were cyto- and hemocompatible in vitro. Therefore, analogous gradient and block copolymers may be alternatively used for specific biomedical applications.