Aqueous electrophoretic deposition of drugs using bile acids as solubilizing, charging and film-forming agents

A new electrophoretic deposition (EPD) technique is reported for the fabrication of composite coatings containing drugs, which have low solubility in water. We present a conceptually new approach, which is based on the use of bile salts (BS) as solubilizing, charging and film forming agents. Composite films are obtained using tetracycline and ibuprofen as model drugs with commercial BS, such as cholic acid sodium salt and deoxycholic acid sodium salt. The suggested mechanism involves the solubilization of drugs in BS solutions, followed by the formation of mixed charged micelles, containing drugs and charged BS, which allow electrophoretic transport of the drugs to the electrode surface. The EPD mechanism involves pH decrease at the anode surface, protonation of carboxylic groups of BS and formation of water insoluble films. The approach can be used for deposition of other functional organic molecules and inorganic nanoparticles.