Compounds corresponding to the general formula: M1-L-M2 in which M1 and M2, which may be identical or different, each represent, independently from each other, a monomer unit M and L represents a connecting group linking M1 and M2 covalently, characterized in that said monomer unit corresponds to the general formula M that follows: ** Formula ** in which - the asterisk * indicates the site of connection between the monomer unit and the connector L, being said link site located of each monomer unit M1 and M2 on one of the substituents R or R2, - R represents a hydrogen atom (in which case the link site of L with M is located on R2) or a group - CONH *, - R1 represents a hydrogen atom or a linear (C1-C3) alkyl group, - R2 represents a -CONH2 group (in which case the link site of L with M is located on R) or - CONH *, - R3 represents a -CO2R4 group, where R4 represents a hydrogen atom or an alkyl group (C1-C4) linear, - X is a halogen atom chosen from fluorine, chlorine and bromine atoms, - L represents the following PEG radicals: in which - the asterisk * indicates the atom for the bond of L with the monomer unit M on the substituent R * or R2 *； - n represents an integer from 2 to 6, in the form of a base or an addition salt with an acid or with a base.Compuestos correspondientes a la fórmula general: M1-L-M2 en la que M1 y M2, que pueden ser idénticos o diferentes, representan cada uno, independientemente uno de otro, una unidad de monómero M y L representa un grupo conector que une M1 y M2 de forma covalente, caracterizados por que dicha unidad de monómero se corresponde con la fórmula general M que sigue: **Fórmula** en la que - el asterisco * indica el sitio de enlace entre la unidad de monómero y el conector L, estando situado dicho sitio de enlace de cada unidad de monómero M1 y M2 sobre uno de los sustituyentes R o R2, - R representa un átomo de hidrógeno (en cuyo caso el sitio de enlace de L con M está situado sobre R2) o un grupo -CONH*, - R1 representa un á
