Pre-Clinical Evaluation of a Modified Cyclodextrin-Based Nanoparticle for Intestinal Delivery of Liraglutide.

New therapeutic approaches have been developed during recent years for the management of diabetic patients, with glucagon-like peptides analogues (GLP-1 analogues) emerging as one of the most useful therapies. However, as with human insulin analogues, translation of GLP-1 analogues into oral pharmaceutical products has been limited due to reduced oral bioavailability. Nanoparticle (NP) formulations have been investigated due to their potential to protect the drug cargo and enhance bioavailability. This study describes the pre-clinical development of a cyclodextrin-based NP formulation containing the GLP-1 analogue liraglutide for intestinal administration. A cationic amphiphilic cyclodextrin (click propyl-amine cyclodextrin (CD)) was selected as the primary complexing agent for the peptide. The resulting NPs presented an average size of 101 ± 8 nm, low polydispersity index (0.240), a negative zeta potential (-35 ± 7 mV), complete association efficiency and peptide loading of 5.0%. The optimized prototype exhibited colloidal stability in intestinal-biorelevant media up to 4 h, protecting the entrapped liraglutide from degradation by proteolytic enzymes. Intestinal administration in rats revealed effective protection and delivery of liraglutide, with a similar pharmacological response in blood glucose levels relative to subcutaneous administration of free solution. These results demonstrate the potential of the CD based formulation for further development.