Materials
Poly(lactic-co-glycolic acid) (PLGA, Resomer® RG 503 H) was purchased from Evonik Industries (Essen, Germany). Poloxamer 407 (P-407), Kollidon® 30 (K30), and Kollidon® VA64 (VA64) were kindly provided by BASF (Ludwigshafen, Germany). Poly(vinyl alcohol) (PVA; Mowiol® 4–88) was obtained from Kuraray Europe GmbH (Hattersheim am Main, Germany). Ovalbumin grade V, as well as all other chemicals, was obtained from Merck KGaA (Darmstadt, Germany). Water was purified with a Milli-Q® system (Merck KGaA; Darmstadt, Germany).