Injectable PLGA/hydrocortisone formulation produced by continuous supercritical emulsion extraction

The objective of the present study was to develop an anti-inflammatory prolonged action formulation for local injection in prefilled syringes. Hydrocortisone acetate (HA) was selected as a model corticosteroid drug to be incorporated in poly(lactic-co-glycolic) (PLGA) microspheres. The formulation was obtained by supercritical emulsion extraction in continuous operation layout (SEE-C) to test the process robustness for a continuous industrial production. PLGA/HA microspheres with mean sizes between 1 mu m (SD +/- 0.20) and 5 mu m (SD +/- 1.45) were obtained when operating at 80 bar and 38 degrees C with a L/G ratio of 0.1 in the counter-current tower. The produced microdevices showed excellent encapsulation efficiencies between 75% and 80%, depending on the emulsion formulations tested, and different sustained release in the range of 6-15 days. In dependence of the different emulsion (single or double) processed by SEE-C, different products can be obtained according to the therapeutic requests. SEE-C confirms to be an innovative and flexible technology for biopolymer microdevices production, coupling the efficiency of continuous operation to the easy process scalability. (C) 2012 Elsevier B. V. All rights reserved.