Dexamethasone delivery of porous PEG-PCL-PEG scaffolds with supercritical carbon dioxide gas foaming

Triblock copolymers of PEG-PCL-PEG (PEGCL) were fabricated using ring opening polymerization (ROP) of epsilon-caprolactone. H-1 NMR and FTIR spectra of the PEGCL triblock were used to confirm the structure and determine the molecular weight. The peaks from -OCH3 and -CH2CH2O- in PEG blocks and -(CH2)(3)-, -COCH2-, and -CH2OCO- within PCL blocks were determined. PEGCL powder was mixed with dexamethasone (DXMT) and then compressed applying a hydraulic pressure of 9 x 10(-2) MPa, which resulted in the formation of disc-like tablets. Following that, the scaffolds with tablet shape were placed into the scCO(2) gas foaming apparatus. Central composite design (CCD) was used to obtain the maximum porosity % with the scCO(2) variables of soaking time (t(s)), pressure (P), temperature (T), and time required to depressurize (t(d)). At the maximum porosity % (79.18%), P, T, T-s, and T-d were 234 bar, 49 degrees C, 2.0 h, and 5 min, respectively. Cumulative in-vitro drug release assay revealed that at post-scCO(2) treatment, the scaffolds delivered an almost complete release (79.18 +/- 1.39%) while at pre-scCO(2) treatment, release percentage was 41.07 +/- 1.72% after 30 days. This confirmed suitable release time and properties for controlled delivery of the dexamethasone loaded in PEG-PCL-PEG (PEGCL) triblock copolymer-based scaffolds. So, using the scCO(2) gas foaming method provides the possibility to construct morphologically and structurally adjustable porous PEG-PCL-PEG scaffolds.

Automated summary

The triblock copolymers of PEG-PCL-PEG (PEGCL) were fabricated using ring-opening polymerization (ROP) of epsilon-caprolactone. The scaffolds with adjustable structure and morphology were constructed using the scCO(2) gas foaming method to provide controlled release of dexamethasone loaded in PEGCL.