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Electrifying Skin Delivery
By: Katie Schaefer, Cosmetics & Toiletries
Posted: November 1, 2010, from the November 2010 issue of Cosmetics & Toiletries.
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Besides optimizing delivery, the team also had to address the tissue damage often caused by the method. “Previous methods of iontophoresis have been found to cause significant damage to the tissue,” said Gibson, who noted that their technology sought to control those factors causing the damage while also enabling the delivery of larger molecules.
The team identified that damage was being caused by one electrode producing acid and the other producing a base, essentially leading to a chemical burn. “Basically, it’s like putting sodium hydroxide at one end or hydrochloric acid at the other end,” said Gibson.
To prevent this chemical burn, the team used the basic principle of buffering to place another molecule within the fluid to scavenge the generation of acids and bases. However, as Gibson notes, “If you use the wrong buffer it might be toxic or interfere with delivery.” Specific to the team’s method is the buffer they chose and the method of buffering the solution, which they could not disclose. Gibson stated further that the molecule as a buffer will depend on the tissue where it is applied.
Iontophoresis and Skin
After effectively delivering macromolecules through the cornea without causing tissue damage, the team has expanded its research to other barriers including the skin. According to Gibson, however, the team has not fully researched the method’s application in skin care or dermatology.
Gibson explains that cosmetic ingredient molecules are 10–100 times smaller than the drug molecules he is currently delivering, and therefore believes this is an achievable target. “If we can deliver the large molecules, we can deliver the smaller ones,” he said, adding that small charged molecules such as retinoic acid and salicylic acid should not be a problem.