Bisphosphonate-polyaspartamide conjugates as bone targeted drug delivery systems

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Drug Delivery Systems

Background:

• Bisphosphonates are crucial for bone targeting due to their high affinity for hydroxyapatite.
• Developing macromolecular carriers can improve drug delivery efficiency and reduce systemic side effects.
• Polyaspartamides offer a versatile backbone for conjugating active molecules.

Purpose of the Study:

• To synthesize novel bisphosphonate-polymer conjugates using polyaspartamide as a backbone.
• To evaluate the physicochemical properties and bone-targeting capabilities of these conjugates.
• To assess the in vivo biodistribution and bone selectivity of the developed macromolecular carriers.

Main Methods:

• Synthesis of bisphosphonate derivatives conjugated to polyaspartamide (PHEA) with and without spacers.
• Physicochemical characterization using size exclusion chromatography and 1H-NMR.
• In vitro hydroxyapatite and ex vivo rabbit bone binding assays.
• In vivo biodistribution studies in rats.

Main Results:

• Successful synthesis of polyaspartamide-bisphosphonate conjugates (PHEA-ABP, PHEA-NRD, PHEA-succinate-ABP, PHEA-caproylcarbamate-ABP).
• Demonstrated in vitro and ex vivo affinity for bone tissue.
• In vivo studies revealed significant bone selectivity and favorable biodistribution of the conjugates over time.

Conclusions:

• Polyaspartamide-bisphosphonate conjugates are effective macromolecular carriers for bone drug delivery.
• These conjugates exhibit promising bone targeting and biodistribution profiles.
• The developed system offers a potential strategy for enhanced bone-specific therapeutic interventions.