Pdlg 5004a

Racemic IBU was kindly donated by Zentiva Group (Prague, Czech Republic). Two PLA commercial grades (Purasorb PDL 02A and PDL 04A) and two PLGA commercial grades (PDLG 5004A and PDLG 7504A) consisting of 50:50 and 75:25 of LA:GA units were graciously provided by Corbion (Gorinchem, The Netherlands). All chemicals were used without further purification. The molecular structures of the used chemicals are depicted in Figure 1, and their selected physicochemical properties are summarized in Section 3.1.

Non-sterilized porcine pericardial membranes (1x1 cm, EMCM, Nijmegen, The Netherlands) were coated on the rough side using a Prism 500 ultrasonic spray coater (USI, Haverhill, MA, USA). Membranes were coated with 4 layers of acetonitrile containing 5% PLGA 5004A (PURASORB PDLG 5004A, Corbion, Amsterdam, The Netherlands), testosterone (Aspen Pharmaceuticals, Durban, South Africa) and micronized alendronate (Polpharma, Starograd Gdański, Poland) resulting in 2 or 68 μg/cm² of testosterone and 20 μg/cm² alendronate. The membranes were dried overnight in a vacuum oven at room temperature. Subsequently, the membranes were coated two or four times with 5% PLGA 5004A in acetonitrile without testosterone and alendronate and dried for 3 nights in a vacuum oven at room temperature. Afterwards membranes were packed into double Tyvek pouches. Final sterilization was performed by gamma irradiation at 25 kGy (Synergy Health, Ede, The Netherlands).

Nanoparticles were prepared with poly (lactic-co-glycolic acid) (PLGA: lactide/glycolide molar ratio 50:50, 0.32 - 0.48 dL/g; PURASORB PDLG 5004A, Corbion, the Netherlands) using a double emulsion solvent evaporation method, as described in detail in the supplemental information. BLG-Pep (previously indicated as Peptide 3) were encapsulated in PLGA nanoparticles for the animal study as previously published (12 (link), 32 (link)). The in vitro release method of BLG-Pep and CpG from the PLGA NP is described in detail in the supplemental method.