Spray dried inhalable ciprofloxacin powder with improved aerosolisation and antimicrobial activity

In this study, the spray drying technique was used to prepare ciprofloxacin microparticles (CFX-MPs) for pulmonary administration. By virtue of its amphoteric properties, CFX was dissolved in either a slightly alkaline or acidic solution depending on the used polymer. Dextran and chitosan were used to prepare the MPs and modify the release characteristics of the drug. Particle surface modification was done with either DPPC or PEG. The effects of the manufacturing and formulation parameters on the drug-polymer interactions were investigated by thermal analysis and infrared spectroscopy. CFX-MPs showed improved aerosolisation properties and the encapsulated drug possessed high antimicrobial activity against two of the common and resistant respiratory pathogens: Pseudomonas aeruginosa and Staphylococus aureus. MPs were safe on the lung epithelial cells. Modulation of particle characteristics and drug release was possible by altering not only the polymer but also the type of the acid from which the powders were spray dried. MPs prepared with glutamic and aspartic acids showed better characteristics than those prepared with acetic and hydrochloric acids. Dextran modified particles showed improved aerosolisation properties and safety on lung epithelial cells.