European Journal of Pharmaceutical Sciences 41 (2010) 60–70 Contents lists available at ScienceDirect European Journal of Pharmaceutical Sciences journal homepage: www.elsevier.com/locate/ejps Engineering gas-foamed large porous particles for efficient local delivery of macromolecules to the lung Francesca Ungaro a , Concetta Giovino a , Ciro Coletta b , Raffaella Sorrentino b , Agnese Miro a , Fabiana Quaglia a,∗ a Department of Pharmaceutical and Toxicological Chemistry, University of Naples Federico II, Via D. Montesano 49, 80131 Naples, Italy b Department of Experimental Pharmacology, University of Naples Federico II, Via D. Montesano 49, 80131 Naples, Italy article info Article history: Received 5 March 2010 Received in revised form 11 May 2010 Accepted 19 May 2010 Available online 25 May 2010 Keywords: Pulmonary delivery Large porous particles PLGA Phospholipids Macromolecules abstract Gas-foamed large porous particles (gfLPP) based on poly(lactic-co-glycolic) acid (PLGA) have been recently suggested as potential carriers for pulmonary drug delivery. In this work, we attempt to engineer gfLPP for efficient local delivery of macromolecules in the lungs. Particles were fabricated by the double emulsion-solvent evaporation technique using ammonium bicarbonate as porogen. To improve parti- cle technological properties, two lipid aid excipients, namely dipalmitoylphosphatidylcholine (DPPC) and 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP), were tested. Preliminary technological stud- ies performed on unloaded gfLPP showed that the addition of an appropriate amount of NH 4 (HCO 3 ), which spontaneously produces CO 2 and NH 3 during solvent evaporation, is essential to achieve a homo- geneous population of highly porous particles with optimal aerodynamic properties. Then, the effect of the presence of DPPC or DOTAP upon the properties of gfLPP containing a model hydrophilic macro- molecule, rhodamine B isothiocyanate–dextran (Rhod-dex), was assessed. We found that in the case of hydrophilic macromolecules unable to interact with PLGA end-groups, such as Rhod-dex, excipient addi- tion is essential to increase the amount of drug entrapped within gfLPP, being as high as 80% only for DPPC- or DOTAP-engineered gfLPP. Also Rhod-dex release profile from gfLPP was strongly affected by excipient addition in the initial formulation, with lipid-engineered gfLPP allowing for a more prolonged release of Rhod-dex as compared to excipient-free gfLPP. A further modulation of Rhod-dex initial release rate could be achieved when DOTAP was used, likely due to the electrostatic interactions occurring between macromolecule and cationic phospholipid. Conceiving the developed gfLPP for drug inhalation, DPPC- and DOTAP-engineered gfLPP displayed optimal MMAD exp values falling within the range 6.1–7.6 m and very low geometric standard deviations (GSD) varying between 1.2 and 1.3. In vivo deposition stud- ies performed after intra-tracheal administration of gfLPP in rats confirmed the ability of the developed dry powders to deposit along bronchia and bronchioles. In perspective, lipid-engineered gfLPP repre- sent a viable alternative to LPP developed so far to achieve local and prolonged release of hydrophilic macromolecules, such as nucleic acids, in the lungs. © 2010 Elsevier B.V. All rights reserved. 1. Introduction In recent years, the inhalation of macromoleculecular drugs has generated tremendous interest as an alternative and more con- venient way for both systemic non-invasive delivery of protein therapeutics (Agu et al., 2001; Laube, 2005; Kumar et al., 2006; Patton and Byron, 2007) and local treatment of chronic lung dis- eases (e.g., COPD, cystic fibrosis) via nucleic acids (Densmore, 2006; Moschos et al., 2008; Séguin and Ferrari, 2009). To this end, the use ∗ Corresponding author. Tel.: +39 81678707; fax: +39 81678707. E-mail address: quaglia@unina.it (F. Quaglia). of carrier-based strategies has been regarded as a useful mean to improve drug therapeutic index by increasing not only the amount of macromolecule reaching the target, but also its stability (Cryan, 2005; Mohamed and van der Walle, 2008). In particular, biodegrad- able large porous particles (LPP) made of poly(lactic-co-glycolic) acid (PLGA) hold great promise for the sustained delivery of macro- molecules in the lungs (Edwards et al., 1998; Ungaro et al., 2006, 2009). Typically, LPP display an aerodynamic diameter much lower than geometric one, respectively facilitating their deep lung depo- sition and reducing macrophage-mediated escape (Edwards et al., 1998). So far, PLGA-based LPP have been adequately engineered into aerosols meeting several important criteria for systemic delivery of 0928-0987/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.ejps.2010.05.011