Electrically enhanced transdermal delivery of a macromolecule

Area of Science:

• Pharmacology
• Biomedical Engineering
• Drug Delivery Systems

Background:

• Transdermal drug delivery offers a non-invasive route for systemic administration.
• Delivery of larger molecules like dextran sulfate via transdermal routes remains challenging.
• Iontophoresis and electroporation are electro-driven techniques for enhancing transdermal transport.

Purpose of the Study:

• To optimize delivery parameters for enhanced transdermal transport of dextran sulfate (5000 Da).
• To investigate the combined effect of iontophoresis and electroporation on dextran sulfate delivery.
• To compare transdermal transport efficiency across pig skin and human epidermis.

Main Methods:

• Utilized full-thickness pig skin and human cadaver epidermis.
• Employed silver-silver chloride electrodes for current delivery (0.5 mA cm⁻²).
• Applied exponential decay pulses for electroporation, followed by iontophoresis with cathode in the donor.

Main Results:

• Dextran sulfate delivery increased with donor concentration up to a saturation point.
• Simultaneous iontophoresis and electroporation (6 pulses, 500 V) doubled delivery compared to iontophoresis alone (276 vs. 144.5 μg cm⁻²).
• Transport efficiency was comparable between pig skin (107.4 μg cm⁻²) and human epidermis (84.9 μg cm⁻²).

Conclusions:

• Successfully demonstrated transdermal delivery of 5000 Da dextran sulfate using iontophoresis.
• Showed that combining iontophoresis with electroporation significantly enhances transdermal drug delivery.
• Validated the use of in vitro skin models for evaluating transdermal delivery parameters.