Alendronate PLGA microspheres with high loading efficiency for dental applications

Area of Science:

• Biomaterials Science
• Drug Delivery Systems
• Nanotechnology

Background:

• Alendronate sodium is a bone protective agent with local efficacy in dental applications.
• Developing alendronate-loaded microspheres faces challenges due to the drug's hydrophilicity and low molecular weight.
• High drug loading efficiency is crucial for effective alendronate delivery systems.

Purpose of the Study:

• To incorporate alendronate sodium into poly(lactide-co-glycolide) (PLGA) microspheres (MS) with high loading efficiency.
• To evaluate different multiple emulsion methods for alendronate sodium microsphere preparation.
• To optimize microsphere characteristics for potential dental and clinical applications.

Main Methods:

• Three multiple emulsion techniques were investigated: water-in-oil-in-water (W/O/W), water-in-oil-in-oil (W/O(1)/O(2)), and solid-in-oil-in-oil (S/O(1)/O(2)).
• Microspheres were characterized for entrapment efficiency, surface morphology, particle size, in vitro drug release, and in vitro polymer matrix degradation.
• The W/O(1)/O(2) emulsion technique yielded alendronate microspheres with maximum drug loading and optimal in vitro performance.

Main Results:

• Alendronate microspheres exhibited a triphasic drug release pattern over 13 days.
• The final rapid release phase correlated with accelerated degradation of the PLGA polymer matrix.
• The W/O(1)/O(2) method proved superior for achieving high drug loading and favorable in vitro characteristics.

Conclusions:

• Biocompatible and biodegradable PLGA microspheres incorporating alendronate sodium were successfully developed with high loading efficiency.
• These microspheres show promise as an effective delivery system for bisphosphonates in dental applications.
• The developed system may also be applicable to other clinical settings requiring bisphosphonate delivery.