Pocketed Microneedles for Drug Delivery to the Skin

Area of Science:

• Biomedical Engineering
• Materials Science
• Dermatology

Background:

• The stratum corneum presents a significant barrier to transdermal drug delivery.
• Microneedle technology offers a minimally invasive strategy to bypass the stratum corneum.
• Existing microneedle methods primarily rely on surface coating for drug application.

Purpose of the Study:

• To investigate the efficacy of microneedles with pre-formed pockets for drug delivery.
• To explore the potential of dip-coating for filling these microneedle pockets with drug formulations.
• To develop and evaluate composite microneedle structures for dual drug delivery.

Main Methods:

• Fabrication of microneedles with varying pocket geometries.
• Dip-coating technique for filling microneedle pockets and surfaces with model drugs.
• Quantification of drug loading capacity within pockets and on surfaces.
• Development of composite microneedles for sequential or localized drug delivery.
• In vitro assessment of drug delivery to targeted skin depths.

Main Results:

• Successful filling of microneedle pockets of diverse sizes and shapes was demonstrated.
• Quantification of drug loading revealed significant capacity within pockets and on surfaces.
• Composite microneedles successfully sequestered one drug in pockets and coated another externally.
• Pocketed microneedles effectively delivered a model drug to specific depths within the skin.

Conclusions:

• Pocketed microneedles represent a versatile platform for controlled transdermal drug delivery.
• The dip-coating method is effective for loading drug formulations into microneedle pockets.
• This technology enables precise control over drug localization and release kinetics.
• Pocketed microneedles hold promise for advanced therapeutic applications requiring targeted skin delivery.