PFD-filled PEG-PLGA microcapsules (diameter of 1.5 ± 0.8 µm) were prepared by an emulsion-evaporation procedure as described before [5]. Briefly, an organic solution of 100 mg PLGA (92% PLGA,

8% PEG-PLGA) and 100 µl PFD in 6 ml methylene selleck chemical chloride was emulsified into 20 ml of an aqueous solution of 1% PVA by using an Ultraturrax T25 (IKA Werke, Staufen, Germany) operating with an S25KV-25G-IL dispersing tool at a velocity of 10,200 rpm. For preparation of PEG-PLGA microspheres (unfilled polymer particles with a diameter of 1.5 ± 0.8 µm) Ultraturrax velocity was changed to 5400 rpm. The used methylene chloride was evaporated under magnetic stirring. Microcapsules (independent of the capsule type) were centrifuged

(199.6 g, 20 min, Biofuge primo R, Heraeus, Hanau, Germany) and washed three times with sterile 0.9% NaCl. The final pellet was resuspended in 10 ml sterile 0.9% NaCl and subsequently filtered using a 2.7 µm pore size syringe filter (Whatman, Dassel, Germany). For the preparation of PFD-filled PEG-PLGA microcapsules with a lower size of 1 ± 0.5 µm, Ultraturrax velocity was changed to 14,000 rpm and a 1.6 µm pore size syringe filter (Whatman, Dassel, Germany) was used as described previously [ 11]. For evaluating frozen sections of various organs after contact with PFD-filled PEG-PLGA microcapsules (diameter of 1.5 µm), 100 µl of a stock solution of Nile red (0.057 mg/ml in methylene chloride) were added to the methylene chloride phase prior to emulsification [12]. All capsules were prepared freshly and were used the same day for animal experiments. VE-821 order A total number of 60 male Wistar rats (Rattus norvegicus, 448 ± 23 g) were obtained from the central animal unit of the Essen University Hospital. Animals were kept under standardized conditions of temperature (22 ± 1 °C), humidity (55 ± 5%), and 12/12-h light/dark cycles with free access to food (ssniff-Spezialdiäten, CYTH4 Soest, Germany) and water. All animals received humane care according to the standards of Annex III of the directive 2010/63/EU of the European Parliament and of the Council of 22 September 2010 on the protection of animals

used for scientific purposes [ 13]. The experimental protocol was approved by the local committee for animal protection based on the local animal protection act. Rats were anesthetized with isoflurane (2.0% in 100% medical O2 at 4.0 l/min for induction, 1.5–2.0% isoflurane in 100% medical O2 at 1.0 l/min throughout the experiment) through face masks connected to a vaporizer (Isofluran Vet. Med. Vapor; Draeger, Luebeck, Germany) and received ketamine (50 mg/kg body weight, subcutaneously) into the right chest wall for analgesia. After local lidocaine administration (5 mg/kg body weight subcutaneously), a median skin-deep inguinal incision of about 2 cm was made along the right groin and a Portex catheter (0.58 mm ID, 0.