Research paper Pharmacokinetic evaluation in mice of amorphous itraconazole-based dry powder formulations for inhalation with high bioavailability and extended lung retention Christophe Duret a,⇑ , Romain Merlos a , Nathalie Wauthoz a , Thami Sebti b , Francis Vanderbist b , Karim Amighi a a Laboratoire de Pharmacie Galénique et de Biopharmacie, Université Libre de Bruxelles, Brussels, Belgium b SMB S.A., Brussels, Belgium article info Article history: Received 11 December 2012 Accepted in revised form 3 March 2013 Available online 21 March 2013 Keywords: Pharmacokinetic Inhalation Dry powder Poorly water-soluble Solid dispersion Insufflation Aspergillosis Antifungal Amorphous abstract Three Itraconazole (ITZ) dry powders for inhalation (DPI) were prepared by spray-drying a mannitol solu- tion in which the ITZ was in suspension (F1) or was in solution without (F2) or with phospholipid (PL) (F3). These powders were endotracheally insufflated in vivo at a single dose of 0.5 mg/kg for pharmaco- kinetic profile (lung and plasma concentration) determination in ICR CD-1 mice. ITZ was crystalline in F1 and assumed to be amorphous in the F2 and F3 formulations. F2 and F3 formulations allowed the in vitro formation of an ITZ supersaturated solution with a maximum solubility of 450 ± 124 ng/ml (F2) and 498 ± 44 ng/ml (F3), in contrast to formulation F1 (<10 ng/ml). As a result of these higher solubilities, absorption into the systemic compartment after endotracheal administration was faster for formulations F2 and F3 (shorter t max ) and in larger quantities compared to the F1 formulation (plasmatic AUC 0–24h of 182 ng h/ml, 491.5 ng h/ml and 376.8 ng h/ml, and t max of 60 min, 30 min and 5 min for F1, F2 and F3, respectively). PL increased the systemic bioavailability of ITZ (determined by the AUC plasma to AUC lung ratio) as a consequence of their wetting and absorption enhancement effect. ITZ lung concentrations after pulmonary administration remained higher than the targeted dose, based on the minimal inhibitory con- centrations for Aspergillus fumigatus (2 lg/g lung ), 24 h post-administration for both F1 and F2 formula- tions. However, this was not the case for formulation F3, which exhibited a faster elimination rate from the lung, with an elimination half-life of 4.1 h vs. 6.5 h and 14.7 h for F1 and F2, respectively. Ó 2013 Elsevier B.V. All rights reserved. 1. Introduction Both invasive and chronic pulmonary aspergillosis (PA) are associated with a high mortality and morbidity rate, especially in immunocompromised and chronic lung disease populations. Classical treatment and prophylaxis for PA consists of oral or intravenous administration of antifungal drug formulations [1]. However, these compounds generate numerous side effects and metabolic interactions that often limit their use and efficacy [2]. Using these common routes of administration, an efficient anti- fungal lung concentration (based on an antifungal minimum inhib- itory concentration, MIC of 2 lg/g lung for Aspergillus fumigatus) is not always guaranteed because of poor tissue penetration or high pharmacokinetic (PK) inter- and intra-individual variability. This insufficient concentration may also lead to a poor survival progno- sis. For these reasons, pulmonary delivery could be an interesting alternative because it delivers antifungal agents directly to the site of infection while maintaining high local lung concentrations and limiting systemic exposure [3]. As part of our research into this approach, we previously devel- oped ITZ-based dry powders for inhalation (DPI). However, ITZ is a poorly soluble active ingredient (solubility in simulated lung fluid 8 ng/ml [4]). Therefore, a strategy allowing ITZ solubility enhancement and dissolution profile acceleration was imple- mented in association with a formulation concept aiming to 0939-6411/$ - see front matter Ó 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.ejpb.2013.03.005 Abbreviations: AUC 0–24h , area-under-the-curve; C max , maximal concentration d ae , aerodynamic diameter; DPI, dry powders for inhalation; DPPC, dipalmitoyl- phosphatidylcholine; FSI, fast screening impactor; HPLC, high performance liquid chromatography; ITZ, itraconazole; ITZ-d9, deuterated itraconazole; K el , elimination constant rate; MDT, mean dissolution time; MMAD, mass median aerodynamic diameter; NGI, next generation impactor; OH-ITZ-d8, deuterated hydroxy-itraco- nazole; OH-ITZ, hydroxy-itraconazole; PA, pulmonary aspergillosis; PL, phospho- lipids; PK, Pharmacokinetic; PSD, particle size distribution; PXRD, powder X-ray diffraction; SD, solid dispersion; SEM, scanning electron microscopy; T max , time to C max . ⇑ Corresponding author. Laboratory of Pharmaceutics and Biopharmaceutics, Université Libre de Bruxelles (ULB), Boulevard du Triomphe, CP-207, Campus de la Plaine, B-1050 Brussels, Belgium. Tel.: +32 2 650 53 31; fax: +32 2 650 52 69. E-mail address: cduret@ulb.ac.be (C. Duret). European Journal of Pharmaceutics and Biopharmaceutics 86 (2014) 46–54 Contents lists available at SciVerse ScienceDirect European Journal of Pharmaceutics and Biopharmaceutics journal homepage: www.elsevier.com/locate/ejpb