Cystic fibrosis (CF) patients suffer from recurrent lung infections mainly bacterial infection such as staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa). Although prophylactic antibiotics are usually prescribed, bacterial resistance is a key challenge. Therefore, there are attempts to identify new antibiotics, particularly those from natural sources, that may enhance the prognosis of the disease. Therefore, the aim of this project was to investigate the use of date fruit extracts as a potential candidate for the development of dry powder inhaler (DPI) with potential biological activity against P. aeruginosa. Date fruit (Phoenix dactylifera L.) consists of flavonoids, polyphenols, minerals and vitamins, and in many studies, it was reported that it had an effect on gram-positive and gram-negative bacteria. When talking about lung diseases, the pulmonary route for drug delivery provides special advantages when compared with other routes. The drugs can reach the site of action more efficiently. Dry powder inhaler (DPI) was employed to deliver the powder formulations. Aqueous date fruit extract: chitosan-based nanoparticles with increasing concentration of chitosan were prepared. Chitosan 0.05% w/v nanoparticles demonstrated the highest encapsulation efficiency (55.91%) and delivered the highest emitted dose (98.92%) and Fine particle fraction of nominated dose (42.62%). Chitosan date nanoparticles (CDN) showed MIC of 4.5 mg/ml and demonstrated a significant inhibition of biofilm formation. CDN is suggested as a potential candidate for the management of cystic fibrosis as an DPI.