Ion channel modulating activity I

1. A method of terminating early afterdepolarization, the method comprising administering to a subject in need thereof an ion channel modulating compound in an amount effective to block the late component of a cardiac sodium channel current approximately as much as or more than it blocks the early component of a cardiac sodium channel current, and also effective to block the early component of a cardiac sodium channel current approximately as much as or more than it blocks the sustained component of a cardiac sodium channel current, wherein the ion channel modulating compound has the following formula (Ia):

or a pharmaceutically acceptable salt thereof;

wherein,

n is 2;

X is —C(R 6 ,R 14 )—Y—, or —C(R 13 )═CH—;

Y is a direct bond, O, S, or C 1 -C 4 alkylene;

R 13 is hydrogen, C 1 -C 6 alkyl, C 3 -C 8 cycloalkyl, aryl, or benzyl;

R 1 and R 2 are independently hydrogen, C 1 -C 8 alkyl, C 3 -C 8 alkoxyalkyl, C 1 -C 8 hydroxyalkyl, or C 7 -C 12 aralkyl; or

R 1 and R 2 , when taken together with the nitrogen atom to which they are directly attached in formula (Ia), form a ring denoted by formula (II):

wherein the ring of formula (II) is formed from the nitrogen as shown as well as three to nine additional ring atoms independently carbon, nitrogen, oxygen, or sulfur; where any two adjacent ring atoms may be joined together by single or double bonds, and where any one or more of the additional carbon ring atoms may be substituted with one or two substituents selected from the group consisting of hydrogen, hydroxy, C 1 -C 3 hydroxyalkyl, oxo, C 2 -C 4 acyl, C 1 -C 3 alkyl, C 2 -C 4 alkylcarboxy, C 1 -C 3 alkoxy, and C 1 -C 20 alkanoyloxy, or may be substituted to form a spiro five- or six-membered heterocyclic ring containing one or two heteroatoms of oxygen or sulfur; and any two adjacent additional carbon ring atoms may be fused to a C 3 -C 8 carbocyclic ring, and any one or more of the additional nitrogen ring atoms may be substituted with substituents of hydrogen, C 1 -C 6 alkyl, C 2 -C 4 acyl, C 2 -C 4 hydroxyalkyl or C 3 -C 8 alkoxyalkyl; or

R 1 and R 2 , when taken together with the nitrogen atom to which they are directly attached in formula (Ia), may form a bicyclic ring system of 3-azabicyclo[3.2.2]nonan-3-yl, 2-azabicyclo[2.2.2]octan-2-yl, 3-azabicyclo[3.1.0]hexan-3-yl, or 3-azabicyclo[3.2.0]heptan-3-yl;

R 3 and R 4 are independently attached to the cyclohexane ring shown in formula (Ia) at the 3-, 4-, 5- or 6-positions and are independently hydrogen, hydroxy, C 1 -C 6 alkyl, or C 1 -C 6 alkoxy, and, when both R 3 and R 4 are attached to the same cyclohexane ring atom, may together form a spiro five- or six-membered heterocyclic ring containing one or two heteroatoms of oxygen or sulfur;

R 5 , R 6 and R 14 are independently hydrogen, C 1 -C 6 alkyl, aryl or benzyl, or R 6 and R 14 , when taken together with the carbon to which they are attached, may form a spiro C 3 -C 5 cycloalkyl;

A is C 5 -C 12 alkyl, a C 3 -C 13 carbocyclic ring, or a ring system having one of the following formulae (III), (IV), (V), (VI), (VII) or (VIII):

where R 7 , R 8 and R 9 are independently bromine, chlorine, fluorine, carboxy, hydrogen, hydroxy, hydroxymethyl, methanesulfonamido, nitro, sulfamyl, trifluoromethyl, C 2 -C 7 alkanoyloxy, C 1 -C 6 alkyl, C 1 -C 6 alkoxy, C 2 -C 7 alkoxycarbonyl, C 1 -C 6 thioalkyl or N(R 15 ,R 16 ) where R 15 and R 16 are independently hydrogen, acetyl, methanesulfonyl, or C 1 -C 6 alkyl;

where R 10 and R 11 are independently bromine, chlorine, fluorine, carboxy, hydrogen, hydroxy, hydroxymethyl, methanesulfonamido, nitro, sulfamyl, trifluoromethyl, C 2 -C 7 alkanoyloxy, C 1 -C 6 alkyl, C 1 -C 6 alkoxy, C 2 -C 7 alkoxycarbonyl, C 1 -C 6 thioalkyl, or N(R 15 ,R 16 ) where R 15 and R 16 are independently hydrogen, acetyl, methanesulfonyl, or C 1 -C 6 alkyl;

where R 12 is bromine, chlorine, fluorine, carboxy, hydrogen, hydroxy, hydroxymethyl, methanesulfonamido, nitro, sulfamyl, trifluoromethyl, C 2 -C 7 alkanoyloxy, C 1 -C 6 alkoxy, C 2 -C 7 alkoxycarbonyl, C 1 -C 6 thioalkyl, or N(R 15 ,R 16 ) where R 15 and R 16 are independently hydrogen, acetyl, methanesulfonyl, or C 1 -C 6 alkyl; and Z is CH, CH 2 , O, N or S, where Z may be directly bonded to “X” as shown in formula (Ia) when Z is CH or N, or Z may be directly bonded to R 17 when Z is N, and R 17 is hydrogen, C 1 -C 6 alkyl, C 3 -C 8 cycloalkyl, aryl or benzyl;

2. The method of claim 1 wherein the ion channel modulating compound blocks a late component of a cardiac sodium channel approximately 20% more than it blocks the early component of a cardiac sodium channel current.

3. The method of claim 1 wherein the early afterdepolarization is induced by a genetic mutation.

4. The method of claim 3 wherein the genetic mutation is long-QT syndrome or Jervell and Lange-Nielsen syndrome.

5. The method of claim 1 , wherein the compound of formula (Ia) has the following structure:

or a pharmaceutically acceptable salt thereof;

wherein R 22 and R 23 are independently hydrogen, hydroxy or C 1 -C 6 alkoxy.

6. The method of claim 5 wherein the ion channel modulating compound is a monohydrochloride salt having the following formula:

7. The method of claim 1 , wherein R 1 and R 2 are independently C 3 -C 8 alkoxyalkyl, C 1 -C 8 hydroxyalkyl, or C 7 -C 12 aralkyl.

8. The method of claim 1 , wherein the compound of formula (Ia) has the following structure:

or a pharmaceutically acceptable salt thereof, wherein, R 21 , R 22 and R 23 are independently hydrogen, hydroxy or C 1 -C 6 alkoxy.

9. The method of claim 1 , wherein the early afterdepolarization is chemically induced.

10. The method of claim 1 wherein the early afterdepolarization induces Torsades de Pointes in the subject.