Novel poly(sulfobetaine methacrylate) based carriers as potential ocular drug delivery systems for timolol maleate

Polyzwitterions are biocompatible and protein‐adsorption‐resistant polymers which makes them very attractive for pharmaceutical applications, especially as drug and gene delivery systems. Two different poly(sulfobetaine methacrylate) (PSB) based vehicles were synthesised in the present study using reversible addition‐fragmentation chain transfer polymerization, namely linear macromolecules and a crosslinked network as microgels, in order to be tested as ocular drug delivery systems for timolol maleate (TM). The differences in their structure were expected to result in different physicochemical properties as well as in different performances as potential ocular drug delivery systems. The PSB vehicles' structure and properties were investigated using dynamic light scattering, zeta potential measurements and SEM. The drug entrapment efficiency of TM in both PSB carriers was determined and the TM release profiles were monitored. In this way, the relationship between the PSB vehicles' structure and the TM release profiles was outlined. © 2022 Society of Industrial Chemistry. Two poly(sulfobetaine methacrylate) (PSB) carriers – linear and crosslinked – were synthesized and applied for timolol maleate ocular delivery. Both release profiles obey a first‐order kinetic model and show quasi‐Fickian diffusion mechanisms. PSB nanoparticles demonstrated a drug release profile more appropriate for ocular application than linear PSB macromolecules.