Lymph directing prodrugs

A compound of the formula (I):

• wherein
• R1 and R2 independently represent H, or a residue of a C2-C28 fatty acid;
• —X— is selected from —O—, —NH— and —S—;
• represents a residue of a pharmaceutical agent;
• -L- is —OC(O)— or —X′—;
• —Y— represents an optionally substituted —C1-C20alkylC(O)OCH2—, —C2-C20alkenylC(O)OCH2— or —C2-C20alkynylC(O)OCH2— group when -L- is —OC(O)—;
• wherein one or more of the carbon atoms in the alkyl, alkenyl or alkynyl group may be replaced with NH, S, O, a C5-C8 aromatic or aliphatic cyclic group or a C5-C8 aromatic or aliphatic heterocyclic group, provided that the alkyl, alkenyl or alkynyl group does not exceed a length equivalent to a linear C20alkyl group;
• or
• —Y— represents an optionally substituted —C1-C2alkylC(O)R3— group or a —C2alkenylC(O)R3— or —C2alkynylC(O)R3— group when -L- is —X′—;
• R3 is a self-immolative group;
• X′ is O, S, N(R4) or N(H)S(O)2;
• R4 is H or C1-C4alkyl;
• or
• pharmaceutically acceptable salts thereof.