Maximizing drug loading in cavity microneedles through precision cavity engineering and centrifugal techniques

Area of Science:

• Materials Science
• Biomedical Engineering
• Pharmaceutical Sciences

Background:

• Cavity microneedles enhance drug loading capacity by utilizing internal structures.
• Challenges include unclear cavity formation mechanisms, reduced mechanical strength, and inefficient drug loading.
• Existing methods suffer from poor reproducibility and low efficiency.

Purpose of the Study:

• Investigate cavity formation principles in microneedles.
• Optimize mechanical properties of cavity microneedles.
• Enhance the efficiency and reproducibility of powder drug loading processes.

Main Methods:

• Analyzed material properties and preparation processes for cavity formation.
• Employed a two-step casting method to improve mechanical performance.
• Utilized discrete element simulation (DEM) to refine centrifugal drug loading.

Main Results:

• Substrate concentration and viscosity are critical for cavity formation.
• Increased centrifugal speed improves drug loading capacity and reduces processing time.
• A novel 'clockwise + counterclockwise' centrifugal method achieved uniform drug loading by mitigating the Coriolis effect.

Conclusions:

• Established a 'process-property-drug loading' optimization chain for soluble cavity microneedles.
• Demonstrated uniform and efficient drug loading through DEM-guided process optimization.
• Validated the potential of cavity microneedles as a high-capacity drug delivery platform with analgesic efficacy.