Thermo-responsive liposomes achieved over 75% teriparatide entrapment using a novel hydrophobic ion pairing technique, with temperature-controlled pulsatile release that preserved the peptide's biological activity.
>75% entrapmentHydrophobic ion pairing achieved over 75% teriparatide entrapment in liposomes — a major improvement over existing methods for trapping water-soluble peptides in lipid carriers
What the researchers found
Hydrophobic ion pairing achieved >75% teriparatide entrapment in sub-200 nm monodispersed liposomes, outperforming other entrapment methods. Transition temperatures of 38-50°C were obtained by modulating phospholipid composition. In vitro assays demonstrated temperature-dependent release kinetics. Released teriparatide maintained biological activity at the PTH1 receptor.
Why it matters
Patient adherence to daily teriparatide injections is poor, limiting the clinical benefit of the only approved bone-building osteoporosis therapy. A delivery system that releases teriparatide in controlled bursts could transform treatment into a longer-acting, more convenient therapy.
The numbers in context
Teriparatide requires pulsatile release (not continuous) for its bone-building anabolic effect.
How the study worked
In vitro formulation study. Hydrophobic ion pairing was used to create a hydrophobic teriparatide complex for liposomal entrapment. Liposomes prepared with various phospholipid compositions to achieve different phase transition temperatures. Characterized by size, dispersity, and entrapment efficiency. Release kinetics tested at different temperatures. Biological activity confirmed using a PTH1 receptor cell-based assay.
Who was studied
In vitro formulation development and characterization
What this study cannot tell us
In vitro proof-of-concept only — no animal or human testing. The practical method of applying heat to trigger release in vivo is not addressed. External heating may be difficult to implement for bone-targeting applications. Long-term stability of the formulation not assessed. Scaling up hydrophobic ion pairing for manufacturing not demonstrated.
How to read the evidence
Rated preliminary: in vitro proof-of-concept with no animal or human data. Demonstrates formulation feasibility but clinical translation is distant.
When this study was published
Published in 2024. First proof-of-concept of thermo-responsive liposomes for pulsatile teriparatide delivery.
The bigger picture
This proof-of-concept addresses two major challenges in peptide drug delivery: efficiently loading water-soluble peptides into lipid carriers, and controlling their release with an external trigger (heat). If developed further, this approach could be applied to many other therapeutic peptides requiring pulsatile delivery.
Questions still open
- How would controlled heating be applied in vivo to trigger teriparatide release at bone sites?
- Could wearable heating devices or focused ultrasound provide the temperature control needed?
- Would the pulsatile release profile from these liposomes match the optimal pharmacokinetics for bone-building?
Common questions
Could teriparatide be given less than once a day?
Why is pulsatile release important for teriparatide?
Read the original research
A lipid-based delivery platform for thermo-responsive delivery of teriparatide.
International journal of pharmaceutics, 667(Pt A), 124853
Citation
Schlosser, Corinna S; Rozek, Wojciech; Mellor, Ryan D; Manka, Szymon W; Morris, Christopher J; Brocchini, Steve; Williams, Gareth R. (2024). A lipid-based delivery platform for thermo-responsive delivery of teriparatide.. International journal of pharmaceutics, 667(Pt A), 124853. https://doi.org/10.1016/j.ijpharm.2024.124853