Imaging compounds for detecting or imaging senescent cells

A compound, or a salt or solvate thereof, according to formula I:

• T-L-D (I)
• wherein
• D is a fluorescent dye moiety selected from:
• (i) a cyanine dye moiety;
• (ii) a BODIPY dye moiety;
• (iii) a coumarin dye moiety;
• and
• (iv) a xanthene dye moiety, with the proviso that the xanthene dye moiety is not fluorescein;
• L is a direct bond or a linking moiety;
• and
• T is a lipid-targeting moiety of formula II or III:
• wherein
• R1 and R2b are each independently selected from hydrogen;
• an optionally substituted (C1-10)alkyl group;
• an optionally substituted aryl group;
• and an optionally substituted aryl(C1-10)alkyl group;
• or
• R1 and R2b, together with the carbon to which they are attached, form an optionally substituted C4 to C12 carbocyclic ring;
• R2a is selected from an optionally substituted (C1-10)alkylene group;
• an optionally substituted arylene group;
• an optionally substituted aryl(C1-10)alkylene group;
• or
• R1 and R2a together with the carbon to which they are attached form an optionally substituted C4 to C12 carbocyclic ring;
• each R3 is independently hydrogen or a (C1-10)alkyl group;
• R4a is selected from hydrogen, halogen, optionally substituted C1-10 alkyl, optionally substituted C1-10 haloalkyl, optionally substituted C1-10 haloalkoxy, —ORA4, —SRA4, —NRA4RB4, —CN, —NO2, —N3, —NRA4C(O)RB4, —C(O)NRA4RB4, —NRA4C(O)ORB4, —OC(O)NRA4RB4, —NRA4C(O)NRA4RB4, —NRA4SO2RB4, —SO2NRA4RB4, —SO2RA4, —NRA4C(S)RB4, —C(S)NRA4RB4, —C(O)RA4, —C(O)ORA4, optionally substituted C3-6 cycloalkyl and an optionally substituted 3-7 membered heterocycloalkyl group;
• q is an integer of value 0, 1, 2 or 3;
• R4b is selected from a direct bond, —O—, —S—, —NRC4—, —NRC4C(═O)—, —C(═O)NRC4—, an optionally substituted (C1-10)alkylene group;
• and an optionally substituted (C1-10)heteroalkylene group;
• and
• RA4, RB4 and RC4, at each occurrence, are independently selected hydrogen, C1-6 alkyl and C1-6 heteroalkyl.