Novel Method of Transdermal Drug Delivery: Iontophoresis

The highly lipophilic nature of the skin restricts the permeation of hydrophilic, high molecular weight and charged compounds through the stratum corneum into the systemic circulation. However, many therapeutically active drug molecules are hydrophilic and possess high molecular weights for example, peptides. Iontophoresis is an alternative drug and cosmetic delivery system. A low-level electrical current is applied to a similarly charged drug or cosmetic solution. Iontophoresis repels the drug ions which diffuse through the skin to the underlying tissue. In contrast to passive transdermal patch drug delivery, iontophoresis is an active (electrically driven) method that allows the delivery of water-soluble ionic drugs that would not be effectively absorbed through the skin without application of a voltage. This presentation provides a general overview on iontophoresis with the emphasis on possible advantages associated with this system, principles, mechanisms associated with them, summarization of different application and factors affecting iontophoresis, evaluation parameter used to determine the feasibility of using iontophoretic delivery devices to facilitate the transdermal transport of hydrophilic charged macromolecules of peptides, such as vasopressin, and proteins, such as insulin, across the skin.