Glycyrrhetinic acid derivatives for use in treating hyperkalemia

A compound of formula I or a salt thereof:

• wherein,
• X is a bond, —O—, —C(O)—, —N(Rx)—, —C(O)N(Rx)—, —N(Rx)—C(O)—, —S(O)n—N(Rx)— or —N(Rx)—S(O)n—;
• L is a bond, alkylene wherein one or more non-adjacent methylene groups of said alkylene are replaced with —O—;
• divalent aryl or divalent heteroaryl;
• or L is alkylene-Y-alkylene wherein Y is O, NRx, S, SO, SO2 or a divalent heterocycle;
• wherein said alkylene groups are optionally substituted with OH, —C(O)O—R1, alkyl or alkyl substituted with OH or —C(O)O—R1;
• and wherein a carbon of said alkylene groups and Rx optionally together form a heterocycle;
• provided that when X is other than a bond, then L is other than a bond;
• W is O or S;
• Q is a bond or alkylene;
• R1 is H, alkyl, a carbocycle or a heterocycle wherein said alkyl, carbocycle and heterocycle are each optionally substituted with halogen, OH, amino, oxo, carboxy, acyloxy, alkoxycarbonyl, alkoxyacyloxy, alkoxycarbonyloxy, aminocarbonyl, a carbocycle optionally substituted with alkyl, haloalkyl, oxo, amino and halogen and a heterocycle optionally substituted with alkyl, oxo, amino and halogen;
• and a carbocycle or heterocycle optionally substituted with alkyl, haloalkyl, oxo, amino and halogen;
• V is —C(O)O—, —C(O)O—(CHR5)—O—C(O)—, —C(O)O—(CHR5)—O—C(O)—O—, —C(O)O—(CH2)n—Y—C(O)N(R5)—, —C(O)N(R5)—O—, —NH—C(O)—N(R5)— or NH—S(O)n—;
• wherein Y is a divalent heterocycle optionally substituted with alkyl, halogen, OH, amino, carboxyl and oxo;
• R2 is H or R5;
• R3 is absent or alkyl;
• R4 is absent, H, OH, ═O, —R6, —O—R6, —C(O)O—R6, —O—C(O)—R6, —O—C(O)—O—R6, —O—C(O)—NR5R6, —NR5R6, —NR5—C(O)—R6, —NR5—C(O)—O—R6, —NR5—SO2—R6, ═N—O—R5;
• R5 is H or alkyl optionally substituted with a carbocycle or heterocycle wherein said carbocycle and heterocycle are optionally substituted with halogen, OH, oxo and alkyl;
• R6 is H, alkyl, a carbocycle, a heterocycle wherein said alkyl, carbocycle and heterocycle are optionally substituted with halogen, OH, SH, alkylthio, —S(O)-alkyl, —SO2-alkyl, amino, —NHC(O)-alkyl, oxo, alkyl, carboxyl, acyl, acyloxy, alkoxy, alkoxycarbonyl, a carbocycle optionally substituted with halogen, OH, amino or alkyl, or a heterocycle optionally substituted with halogen, OH, amino or alkyl;
• and wherein one or more non-adjacent methylene groups in each of said alkyl groups of R6 are optionally replaced with —O— or —S—;
• Rx is H, —C(O)O—R1, or alkyl optionally substituted with —C(O)O—R1;
• and
• n is 1 or 2.