1 Pharmaceutical nanotechnology 2 Fabrication of polyelectrolyte multilayered vesicles as inhalable dry 3 powder for lung administration of rifampicin 4 Maria Letizia Manca a Q1 , Donatella Valenti a , Octavio Diez Sales b , Amparo Nacher b , 5 Anna Maria Fadda a , Maria Manconi a, * 6 a Department of Environmental and Life Science, Q2 University of Cagliari, Via Ospedale 72, Cagliari 09124, Italy 7 b Department of Pharmacy and Pharmaceutical Technology, University of Valencia, Burjassot, Valencia 46100, Spain A R T I C L E I N F O Article history: Received 17 April 2014 Received in revised form 5 June 2014 Accepted 8 June 2014 Available online xxx Keywords: Rifampicin Coated liposomes Chitosan Carrageenan Pulmonary delivery Next-generation impactor A B S T R A C T A polyelectrolyte complex based on chitosan and carrageenan was used to coat rifampicin-loaded vesicles and obtain a dry powder for inhalation by spray-drying. The polymer complexation on vesicle surface stabilized them and improved their adhesion on airways and epithelia cells. Uncoated liposomes were small in size, negatively charged and able to incorporate large amounts of rifampicin (70%). Coated vesicles were still able to load adequate amounts of drug (70%) but the coating process produced larger particles (1 mm) that were positively charged and with a spherical shape. Aerosol performances, evaluated using the next-generation impactor, showed that coated vesicles reached the 50% of fine particle fraction and the smallest mass median aerodynamic diameter (2 mm). Rifampicin-loaded uncoated and coated vesicles slowly reduced the A549 cell viability over a 48-h incubation time. Moreover, in vitro coated formulations had a strong ability to be easily internalized and to greatly prolong the residence time of their components in A549 cells compared to uncoated liposomes that were rapidly internalized and just as quickly removed. ã 2014 Published by Elsevier B.V. 8 1. Introduction 9 Pulmonary drug delivery systems have been increasingly 10 studied and developed thanks to their suitability to quickly allow 11 high local or systemic drug bioavailability avoiding the first-pass 12 effect (Mahajan and Gundare, 2013; Mansour et al., 2009; Mura 13 et al., 2011b). Lungs may be used as a route of administration for 14 local pulmonary diseases such as asthma, bronchitis and 15 emphysema and other severe diseases that compromise the lungs 16 functionality, including cystic fibrosis, tuberculosis, pulmonary 17 vascular disorders and interstitial lung disorders, or for systemic 18 diseases (Nahar et al., 2013). In particular, inhalable drug delivery 19 systems represent a viable alternative to administer local medica- 20 ments to different sites of the respiratory tree (Kawashima et al., 21 1998). To reach therapeutic efficacy, inhalable drug formulations 22 must efficiently arrive and deposit in the airways and their 23 aerodynamic size and aerosolization properties are crucial 24 parameters to control the drug deposition in the desired region 25 of the lungs. Moreover, the lung retention of formulations and their 26 ability to cross lung barriers are additional advantages to improve 27 therapeutic efficacy, which can be limited by the mucociliary 28 clearance (Mansour et al., 2009; Pison et al., 2006). 29 Rifampicin (3-(4-methyl-l-piperazinyl-irninomethyl) rifampi- 30 cin) is one of the most potent and broad-spectrum antibiotics, 31 frequently used for different pulmonary diseases (Suarez et al., 2001; 32 Sung et al., 2009). Additionally, it represents the first-choice 33 antibiotic when drug resistance develops during chronic treatments 34 of different diseases such as tuberculosis or cystic fibrosis. 35 Unfortunately, this drug is poorly adsorbed after oral administration 36 and doses required to obtain the therapeutic effects are generally too 37 high and associated with various side effects. Administration of 38 rifampicin to the lungs by dry powder formulations may improve its 39 local bioavailability and efficacy, increasing the patient compliance 40 (Coowanitwong et al., 2008; Sung et al., 2009). Among different 41 colloidal systems, rifampicin-loaded liposomes have been widely 42 studied as an inhalable drug delivery system able to effectively 43 improve their pulmonary distribution and bioavailability (Manca 44 et al., 2008, 2012; Zaru et al., 2007, 2009b). Nevertheless, the use of 45 liposomes is Q3 limited by their stability in solution and biological 46 environment, and equally significant is their poor stability during the * Corresponding author. Tel.: +39 0706758542; fax: +39 0706758553. E-mail address: manconi@unica.it (M. Manconi). http://dx.doi.org/10.1016/j.ijpharm.2014.06.009 0378-5173/ ã 2014 Published by Elsevier B.V. International Journal of Pharmaceutics xxx (2014) xxx–xxx G Model IJP 14134 1–8 Please cite this article in press as: Manca, M.L., et al., Fabrication of polyelectrolyte multilayered vesicles as inhalable dry powder for lung administration of rifampicin, Int J Pharmaceut (2014), http://dx.doi.org/10.1016/j.ijpharm.2014.06.009 Contents lists available at ScienceDirect International Journal of Pharmaceutics journal homepage: www.elsev ier.com/locate /ijpharm