Compounds of the formula in which R1 and R2 independently of one another represent hydrogen, fluorine, chlorine, nitrile, trifluoromethyl, pentafluoroethyl, methoxy, ethoxy, trifluoromethoxy, -OCH 2 CF 3, CH 3 SO 2 -, CH 3 CH 2 SO 2 -, - (C=O)CH 3, carboxyl, C 1 -C 4 -alkyl, hydroxy, -CH 2 OH, -C(CH 3) 2 OH, -CONH 2, -(C=O)NH-alkyl, -(C=O)N(CH 3) 2, -SO 2 NH 2, -SO 2 NH(CH 3), -SO 2 N(CH 3) 2 or the replacement of a C-H group in the pyridine ring by a nitrogen atom and R3 and R4 represent hydrogen or R3 represents hydroxy, fluorine, methoxy or ethoxy and R4 represents hydrogen or R3 represents hydrogen and R4 represents hydroxy, fluorine, methoxy or ethoxy and R5 and R6 represent hydrogen or R5 represents fluorine, hydroxy, methoxy or ethoxy and R6 represents hydrogen or R5 represents hydrogen and R6 represents fluorine and R7 represents hydrogen, C 1 -C 4 -alkyl, C 3 -C 6 -Cycloalkyl, cyclopropylmethyl, trifluoromethyl or 2,2,2-trifluoroethyl and R8 represents -CR a R b -COOH where R a and R b independently of one another represent hydrogen, methyl, ethyl or R a and R b together represent -(CH 2) n - where n = 2, 3, 4 or 5, where up to 4 hydrogen atoms of the CH 2 groups may be replaced by fluorine atoms or R a and R b together represent -CH 2 -O-CH 2 -, -CH 2 -NH-CH 2 -, -CH 2 -N(CH 3)-CH 2 -, -CH 2 CH 2 -O-CH 2 CH 2 -, -CH 2 CH 2 -NH-CH 2 CH 2 -, -CH 2 CH 2 -N (CH 3) -CH 2 CH 2 - or R a represents hydrogen, methyl or ethyl and R b together with R7 represents - (CH 2) n - where n = 1, 2, 3, 4, where up to 4 hydrogen atoms of the CH 2 groups may be replaced by fluorine atoms or R a together with R7 represents -CH 2 -O-CH 2 CH 2 -, - CH 2 -N(CH 3)-CH 2 CH 2 - and R b represents hydrogen, methyl or ethyl or represents -CR c R d -CR e R f -COOH where R c, R d, R e, R f represent hydrogen or R c, R d independently of one another represent methyl, ethyl or together represent -(CH 2) n -where n = 2, 3, 4, 5 or -CH 2 CH 2 -O-CH 2 CH 2 - and R e, R f represent hydrogen or R c, R d represent hydrogen and R e, R f independently of one another represent methyl, ethyl or together represent -(CH 2)n- where n = 2, 3, 4, 5, -CH 2 CH 2 -O-CH 2 CH 2 -, -CH 2 CH 2 -NH-CH 2 CH 2 -, -CH 2 CH 2 -N(CH 3)-CH 2 CH 2 - or -CH 2 -O-CH 2 - or R c represents methyl, ethyl, trifluoromethyl and R d, R e and R f represent hydrogen or R c, R d and R f represent hydrogen and R e represents methyl, ethyl, trifluoromethyl, hydroxy or methoxy or R c and R e together represent -(CH 2) n - where n = 1, 2, 3 or 4 and R d and R f represent hydrogen or represents -CH 2 -CH 2 -CHR g -COOH where R g represents hydrogen or R g and R7 together represent -CH 2 - or -CH 2 CH 2 - and their salts, solvates and solvates of the salts. R1 and R2 independently of one another represent hydrogen, fluorine, chlorine, nitrile, trifluoromethyl, pentafluoroethyl, methoxy, ethoxy, trifluoromethoxy, -OCH 2 CF 3, CH 3 SO 2 -, CH 3 CH 2 SO 2 -, - (C=O)CH 3, carboxyl, C 1 -C 4 -alkyl, hydroxy, -CH 2 OH, -C(CH 3) 2 OH, -CONH 2, -(C=O)NH-alkyl, -(C=O)N(CH 3) 2, -SO 2 NH 2, -SO 2 NH(CH 3), -SO 2 N(CH 3) 2 or the replacement of a C-H group in the pyridine ring by a nitrogen atom and R3 and R4 represent hydrogen or R3 represents hydroxy, fluorine, methoxy or ethoxy and R4 represents hydrogen or R3 represents hydrogen and R4 represents hydroxy, fluorine, methoxy or ethoxy and R5 and R6 represent hydrogen or R5 represents fluorine, hydroxy, methoxy or ethoxy and R6 represents hydrogen or R5 represents hydrogen and R6 represents fluorine and R7 represents hydrogen, C 1 -C 4 -alkyl, C 3 -C 6 -Cycloalkyl, cyclopropylmethyl, trifluoromethyl or 2,2,2-trifluoroethyl and R8 represents -CR a R b -COOH where R a and R b independently of one another represent hydrogen, methyl, ethyl or R a and R b together represent -(CH 2) n - where n = 2, 3, 4 or 5, where up to 4 hydrogen atoms of the CH 2 groups may be replaced by fluorine atoms or R a and R b together represent -CH 2 -O-CH 2 -, -CH 2 -NH-CH 2 -, -CH 2 -N(CH 3)-CH 2 -, -CH 2 CH 2 -O-CH 2 CH 2 -, -CH 2 CH 2 -NH-CH 2 CH 2 -, -CH 2 CH 2 -N (CH 3) -CH 2 CH 2 - or R a represents hydrogen, methyl or ethyl and R b together with R7 represents - (CH 2) n - where n = 1, 2, 3, 4, where up to 4 hydrogen atoms of the CH 2 groups may be replaced by fluorine atoms or R a together with R7 represents -CH 2 -O-CH 2 CH 2 -, - CH 2 -N(CH 3)-CH 2 CH 2 - and R b represents hydrogen, methyl or ethyl or represents -CR c R d -CR e R f -COOH where R c, R d, R e, R f represent hydrogen or R c, R d independently of one another represent methyl, ethyl or together represent -(CH 2) n -where n = 2, 3, 4, 5 or -CH 2 CH 2 -O-CH 2 CH 2 - and R e, R f represent hydrogen or R c, R d represent hydrogen and R e, R f independently of one another represent methyl, ethyl or together represent -(CH 2)n- where n = 2, 3, 4, 5, -CH 2 CH 2 -O-CH 2 CH 2 -, -CH 2 CH 2 -NH-CH 2 CH 2 -, -CH 2 CH 2 -N(CH 3)-CH 2 CH 2 - or -CH 2 -O-CH 2 - or R c represents methyl, ethyl, trifluoromethyl and R d, R e and R f represent hydrogen or R c, R d and R f represent hydrogen and R e represents methyl, ethyl, trifluoromethyl, hydroxy or methoxy or R c and R e together represent -(CH 2) n - where n = 1, 2, 3 or 4 and R d and R f represent hydrogen or represents -CH 2 -CH 2 -CHR g -COOH where R g represents hydrogen or R g and R7 together represent -CH 2 - or -CH 2 CH 2 -