摘要 |
An improved cathodic iontophoresis electrode assembly (8, 38) is provided having a reducible cathodic electrode (12,22) and a drug reservoir (14, 24) containing an anionic drug. The cathodic electrode (12, 22) is separated from the drug reservoir (14, 24) by means of a layer (30) of a cation exchange material. The cation exchange material is loaded with cations which are able to react with anions produced during reduction of the electrode (12, 22) to form an electrically neutral or substantially insoluble (eg, water insoluble) compound. The cathodic electrode (12, 22) is preferably composed of silver chloride which produces chloride ions during reduction. The cation exchange material is preferably loaded with silver or copper cations which react with the chloride ions to produce a neutral and relatively insoluble metal chloride salt.
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