Claimed are a compound of the general formula (I) and pharmaceutically acceptable salts thereof, where M signifies metal atoms selected independently from the group comprising Pd, Fe, Mn, Co, Ni, Cu, Zn and Mo R1 and R2, independently of each other, signify hydrogen, amino, hydroxy, oxy, carboxy, cyano, C1-12alkyl, C2-12alkenyl, C2-12alkynyl, C1-12alkoxy, C1-12alkylamino, C1-12alkoxycarbonyl, C1-12alkylamido, arylamido, wherein the alkylene groupings in the given substituents can in turn be substituted by one or more of the following groups: hydroxy, oxy, carboxy, amino or amido R3-R10, independently of each other, signify hydrogen or NHR3R4 and NHR5R6, taken together, and/or NHR7R8 and NHR9R10, taken together, are a ligand (or ligands) containing one or several donor aliphatic or aromatic atoms of nitrogen and being in cis position on the metal atoms (M). The claimed compound can be used in a preparation containing a coordination compound and free molecules of an aliphatic thiol (or derivatives thereof), which are not bound to the coordination compound. The coordination compound and the free molecules of an aliphatic thiol (or derivatives thereof) in the preparation can be in either cationic or anionic form or in the form of neutral particles. The proposed substances are capable of making the action of drugs more effective by increasing the affinity of the target to the drug and/or providing for therapeutically optimal concentrations of the drug in the microenvironment of the target and/or reducing the toxicity of drugs.L’invention concerne une composition possédant la formule générale (II) et ses sels pharmaceutiquement acceptables, M désignant les atomes d’un métal sélectionné indépendamment dans un groupe comprenant Pd, Fe, Mn, Co, Ni, Cu, Zn et Mo, R(1) et R(2) désignant indépendamment hydrogène, amino, hydroxy, oxy, carboxy, cyano, alkyle C(1-12), alcényle (2-12), alkynil C(2-12), alxoxy C(1-12), alkylamino C(1-12), alcoxycarbonyl C(1-12), alkylamido C(1-12),
