Herein, four different strategies were explored covering the different mechanisms of drug loading. The strategies comprised simple mixing via a fluidic, controlled ethanol injection process, dehydration-rehydration, and charged liposomal adsorption. Finally, hydrophobic ion pairing (HIP) a well-known approach to enhance peptide loading within lipid-based delivery systems such as self-emulsifying drug delivery systems (SEDDS) and solid lipid nanoparticles, was explored for the first time as a strategy to enhance entrapment of peptides within liposomes . All methods were compared for their efficiency of entrapping teriparatide into liposomes. The efficiencies of different entrapment methods are shown Figure . It can be observed that when direct mixing or DRV was used to obtain peptide loading into preformed liposomes, the encapsulation efficiencies were poor, with less than 10% of the peptide entrapped (8.6 ± 12.3 % and 4.1 ± 0.6 % respectively). The liposomes were composed of two zwitterionic lipids (DPPC and DSPC) presenting a net neutral charge. The incorporation of oleic acid into these liposomes (Ion) prior to dehydrationrehydration of the physical mix of liposomes and teriparatide resulted in a significant increase in teriparatide loading (74.3 ± 11.6%). The incorporation of oleic acid into the lipid composition conferred the (unloaded) liposomes a negative charge with oleic acid liposomes presenting a zeta potential of -24.0 ± 2.4 mV compared to 0.6 ± 3.5 mV without oleic acid. The dramatic increase in loading could be explained by electrostatic interactions of the overall positively charged teriparatide (pI = 8.3) with the negative charges of oleic acid. Further, this is consistent with the literature, where adsorption of various polypeptides resulted in high loading efficiencies. Indeed, van Slooten et el. achieved high association with >90% of human IFNγ through association with negatively charged phospholipids .