Methods, compounds, and compositions for delivering 1,3-propanedisulfonic acid

A compound of Formula II:

• wherein,
• R3 is selected from hydrogen and a substituted or unsubstituted group selected from C1-C12alkyl, C2-C12alkenyl, C2-C12alkynyl, C3-C15cycloalkyl, C3-C15heterocycloalkyl, C6-C15aryl, and C5-C15heteroaryl;
• R4 is a substituted or unsubstituted group selected from C1-C12alkyl, C2-C12alkenyl, C2-C12alkynyl, C3-C15 cycloalkyl, C3-C15heterocycloalkyl, C6-C15 aryl, and C5-C15heteroaryl;
• wherein at least one of R3 and R4 is a group selected from Formula B, E and F:
• wherein,
• R6, R7 and R8 are each independently a substituted or unsubstituted group selected from C1-C6alkyl, C2-C6alkenyl, C2-C6alkynyl, C3-C6cycloalkyl, C3-C6heterocycloalkyl, C6-C10aryl, C5-C10heteroaryl, NH2, and NHC(O)OC1-C6alkyl;
• or R7 and R8 are taken together with their adjacent carbon atom to form a group selected from C3-C8cycloalkyl and C3-C8heterocycloalkyl;
• or R6, R7 and R8 are taken together with their adjacent carbon atom to form a C4-C10cycloalkyl fused ring, a C4-C10heterocycloalkyl fused ring, or a C5-C10heteroaryl;
• R22 is a hydrogen atom or a group selected from C1-C6alkyl, C(O)OH, or C(O)OC1-C6alkyl;
• W—Y—Z is selected from C(O)OCH2, OC(O)CH2, CH2C(O)O, and CH2OC(O);
• Rw, Rx, and Ry are each independently selected from a hydrogen atom or a substituted or unsubstituted C1-C3alkyl group, or Rw and Rx are taken together with their adjacent carbon atoms to form a double bond;
• Rz is a substituted or unsubstituted group selected from C1-C12alkyl, C2-C12alkenyl, C2-C12alkynyl, C3-C15 cyclo alkyl, C3-C15heterocycloalkyl, C6-C15aryl, C5-C15heteroaryl, OC1-C12alkyl, OC2-C12alkenyl, OC2-C12 alkynyl, OC3-C15 cycloalkyl, OC3—OC15heterocycloalkyl, OC6-C15aryl, and OC5-C15heteroaryl;
• and
• k is an integer selected from 0, 1 and 2;
• or a pharmaceutically acceptable salt or solvate thereof.