Methods and compositions for disrupting biofilm utilizing chitosan-derivative compounds

A method of disrupting a preformed biofilm in a subject infected with bacteria selected from the group consisting of Burkholderia cepacia genomovar cenocepacia, Burkholderia cepacia genomovar dolosa, Burkholderia cepacia complex, Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter baumanii, Streptococcus pneumoniae, and Klebsiella pneumoniae, the method comprising:

• administering to the subject by inhalation a therapeutically effective amount of a composition comprising a derivatized chitosan wherein the derivatized chitosan comprises a chitosan of the following formula (I):
• wherein:
• n is an integer between 20 and 6000;
• and
• each R1 is independently selected for each occurrence from hydrogen, acetyl, and a group of formula (II):
• wherein formula (II) is selected from
• wherein at least 25% of R1 substituents are H, at least 100 of R1 substituents are acetyl, and at least 4-30% of R1 substituents are a group of formula (II) the molecular weight of the derivatized chitosan is between 10,000 and 150,000 Da, and the polydispersity index (PDI) of the derivatized chitosan is between 1.5 and 2.5, wherein, upon administration, the composition disrupts the preformed biofilm in the respiratory system of the subject and reduces the viscosity of sputum in the respiratory system of the subject relative to the sputum prior to administration of the composition.