Apparatus for iontophoretic drug delivery

Claim 2

Iontophoretic drug delivery apparatus having an electrode assembly (10) comprising an electrode member (22,23) in electrical connection to a source (18,19,21) for an ionic drug species to be delivered iontophoretically and for counterions therefor, characterized in that said electrode assembly contains at least one electrochemically active component in electrical connection to said source and in that at least one of said electrochemically active component and said counterions is such that in the operation of said apparatus water electrolysis at said electrode member is substantially avoided and/or ionic products of water electrolysis at said electrode member are substantially neutralized.

Claim 3

Apparatus as claimed in claim 1 wherein at least one electrode assembly (10) includes a component which is electrochemically active during iontophoretic drug delivery to produce a first species which, with a second species employed in or generated during the operation of said apparatus, is capable of interacting to produce a product which is not sufficiently influenced by electrical fields to be iontophoretically introduced.

Claim 4

Apparatus as claimed in either of claims 1 and 2 further comprising support means (12) for supporting said source and/or said electrode member.

Claim 5

Apparatus as claimed in claim 3 wherein said support means comprises a flexible backing member (12).

Claim 6

Apparatus as claimed in any one of claims 1 to 4 wherein said source comprises a gel reservoir (18) containing therein the drug to be delivered iontophoretically.

Claim 7

Apparatus as claimed in claim 5 wherein said drug is in said gel at a concentration of less than 0.5 molar.

Claim 8

Apparatus as claimed in any one of claims 1 to 6 wherein said electrode assembly contains as an electrochemically active component a current distribution member (22,23).

Claim 9

Apparatus as claimed in claim 7 having a said electrode assembly selected from the following: (a) an electrode assembly having a silver current distribution member and wherein said counterions for said drug species present in said source comprise chloride ions; (b) an electrode assembly having a current distribution member comprising an intercalation compound and wherein said counterions for said drug species present in said source comprise alkali metal ions; (c) an electrode assembly having a current distribution member comprising an amalgam and wherein said counterions for said drug species present in said source comprise alkali metal ions; (d) an electrode assembly having a current distribution member comprising a metallic salt in contact with a metallic cathode; and (e) an electrode assembly having a current distribution member comprising silver chloride in contact with a silver cathode and wherein said counterions for said drug species present in said source comprise silver ions.

Claim 10

Apparatus as claimed in claim 7 comprising an electrode assembly having a current distribution member of a material such that on operation of said apparatus water electrolysis occurs at said electrode assembly thereby releasing acidic or basic ions and wherein the drug present in said source is in a basic or an acidic form respectively.

Claim 11

Apparatus as claimed in claim 9 comprising an electrode assembly having a current distribution member of stainless steel or platinum and wherein the drug present in said source is in the form of a weak acid or a weak base.

Claim 12

Apparatus as claimed in any one of the preceding claims having an anodic electrode assembly the cathode whereof comprises a material selected from: (a) materials having a high hydrogen over voltage; (b) lead, mercury or mercury/cadmium amalgams; and (c) intercalation compounds.

Claim 13

Apparatus as claimed in either of claims 5 and 11 wherein said intercalation compound is an intercalate of a material selected from sodium tungstate, sodium vanadate (NaV 6 0 3 ) and graphite.

Claim 14

An iontophoretic drug delivery electrode assembly (10) comprising an electrode member (22,23) in electrical connection to a source (18,19,21) for an ionic drug species to be delivered iontophoretically and for counterions therefor, characterized in that said assembly contains at least one electrochemically active component in electrical connection to said source and in that at least one of said electrochemically active component and said counterions is such that in the operation of said assembly water electrolysis at said electrode member is substantially avoided and/or ionic products of water electrolysis at said electrode member are substantially neutralized.

Claim 15

An iontophoretic drug delivery electrode assembly (10) comprising an electrode member (22,23) in electrical connection to a source (18,19,21) for an ionic drug species to be delivered iontophoretically and for counterions therefor, characterized in that said assembly contains at least one electrochemically active component in electrical connection to said source and in that at least one of said electrochemically active component and said counterions is such that in the operation of said assembly water electrolysis at said electrode member is substantially avoided and/or ionic products of water electrolysis at said electrode member are substantially neutralized.

Claim 16

An iontophoretic drug delivery electrode assembly (10) comprising an electrode member (22,23) in electrical connection to a source (18,19,21) for an ionic drug species to be delivered iontophoretically and for counterions therefor, characterized in that said assembly contains at least one electrochemically active component in electrical connection to said source and in that at least one of said electrochemically active component and said counterions is such that in the operation of said assembly generation of ionic species at said electrode member is substantially avoided or ionic species qenerated at said electrode member are substantially entirely converted by species present or generated in or at said source and/or said electrochemically active component into species having lower susceptibility to iontophoretic delivery from said assembly.

Claim 17

An iontophoretic drug delivery electrode assembly (10) comprising an electrode member (22,23) in electrical connection to a source (18,19,21) for an ionic drug species to be delivered iontophoretically and for counterions therefor, characterized in that said assembly contains at least one electrochemically active component in electrical connection to said source and in that at least one of said electrochemically active component and said counterions is such that in the operation of said assembly generation of ionic species at said electrode member is substantially avoided or ionic species qenerated at said electrode member are substantially entirely converted by species present or generated in or at said source and/or said electrochemically active component into species having lower susceptibility to iontophoretic delivery from said assembly.

Claim 18

An electrode assembly as claimed in either of claims 13 and 14 wherein said electrode member comprises silver and said source comprises propranolol hydrochloride.