Abstract
Purpose: :
Polyesteramides (PEAs) are a new family of polymeric materials. PEAs combine good mechanical, thermal and processing properties and are also biodegradable. The purpose of the current study was to evaluate PEA-II microparticles to be used as carriers for controlled drug delivery in the eye.
Methods: :
Microparticles (MPs) were prepared using an emulsion-solvent evaporation technique. Particle size and morphology of MPs were characterized by dynamic light scattering and scanning electron microscopy (SEM), respectively. To study the in vitro degradation behavior, MPs were incubated in a phosphate buffered solution isotonized with NaCl (PBS, pH 7.4, 37ºC) at a constant agitation speed of 100 rpm. At different time points (1 hour, 24 hours, 48 hours and 5 days) MPs morphology was studied by SEM. In vitro tolerance studies were performed by the MTT technique in human corneal limbal epithelial cells and macrophage cells. Cells were exposed to MPs suspensions (5mg and 10mg MPs/ml in PBS) for 15 minutes (short term exposure), 1 hour and 4 hours (long term exposure). Dexamethasone (DX) was used as a lipophilic drug model to determine the encapsulation efficiency of PEA-II MPs (0.5:10 DX:PEAII).
Results: :
Unloaded PEA-II MPs were spherical and had smooth surface. MPs size ranged between 10-30µm (mean particle size 21.3±0.2 µm). MPs started to lose their shape after being incubated in PBS for 1 hour. 5 days later, MPS had turned into an unshaped depot of polymer. The cytotoxicity assays demonstrated good tolerance in the two cell lines in all cases after short- and long-term exposures (cell viability>90%) at the assayed concentrations. DX-loaded MPs (9.62±0.56 µg DX/mg MPs and mean particle size 21.3±1.8 µm) did not show any morphological difference with unloaded MPs.
Conclusions: :
Biodegradable PEA-II MPs are potentially useful to develop new controlled drug delivery systems for treating ophthalmic diseases.