Passive and Iontophoretic Delivery of Three Diclofenac Salts Across Various Skin Types

The study investigated the in vitro permeation of three diclofenac salts—diclofenac sodium (DFS), diclofenac potassium (DFP), and diclofenac diethylammonium (DFD)—across various skin types using both passive and iontophoretic transport. It was found that the intercellular route was significant for the passive permeation of DFS and DFP, with the transfollicular route being important for DFS but not DFP. For iontophoresis, DFD utilized hair follicles more than DFS and DFP, while the intercellular lipid pathway was less significant for DFD. The combination of iontophoresis and cardamom oil did not enhance permeation synergistically. The study concluded that the transdermal delivery mechanism and route of diclofenac salts are influenced by their counterions.