Comparison between Colistin Sulfate Dry Powder and Solution for Pulmonary Delivery

• Published in: Pharmaceutics Vol. 12; no. 6; p. 557
• Main Authors: Tewes, Frédéric, Brillault, Julien, Gregoire, Nicolas, Olivier, Jean-Christophe, Lamarche, Isabelle, Adier, Christophe, Healy, Anne-Marie, Marchand, Sandrine
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 17-06-2020; MDPI
• Subjects: Antibiotics; Calu-3 permeability; colistin dry powder inhalation; Experiments; Human health and pathology; Infectious diseases; Inhalers; Life Sciences; nebulization; Particle size; Pharmaceutical sciences; Pharmacokinetics; pharmacokinetics modeling; Pharmacology; pulmonary infections; Pulmonology and respiratory tract; Scanning electron microscopy; United Kingdom > UK; France; United States > US; colistin dry powder inhalation; pharmacokinetics modeling; Calu-3 permeability; pulmonary infections; nebulization
• ISSN: 1999-4923; 1999-4923
• DOI: 10.3390/pharmaceutics12060557

To assess the difference in the fate of the antibiotic colistin (COLI) after its pulmonary delivery as a powder or a solution, we developed a COLI powder and evaluated the COLI pharmacokinetic properties in rats after pulmonary administration of the powder or the solution. The amorphous COLI powder prepared by spray drying was characterized by a mass median aerodynamic diameter and fine particle fraction of 2.68 ± 0.07 µm and 59.5 ± 5.4%, respectively, when emitted from a Handihaler®. After intratracheal administration, the average pulmonary epithelial lining fluid (ELF): plasma area under the concentration versus time curves (AUC) ratios were 570 and 95 for the COLI solution and powder, respectively. However, the same COLI plasma concentration profiles were obtained with the two formulations. According to our pharmacokinetic model, this difference in ELF COLI concentration could be due to faster systemic absorption of COLI after the powder inhalation than for the solution. In addition, the COLI apparent permeability (Papp) across a Calu-3 epithelium model increased 10-fold when its concentration changed from 100 to 4000 mg/L. Based on this last result, we propose that the difference observed in vivo between the COLI solution and powder could be due to a high local ELF COLI concentration being obtained at the site where the dry particles impact the lung. This high local COLI concentration can lead to a local increase in COLI Papp, which is associated with a high concentration gradient and could produce a high local transfer of COLI across the epithelium and a consequent increase in the overall absorption rate of COLI.