Compound of formula: ** Formula ** where G is selected from CONH2 and CSNH2; And it is a pharmaceutically acceptable counterion; Q is selected from alkyl and benzyl; R2 and R2a are both hydrogen or R2 and R2a together are>; = O; R3 is selected from hydrogen, cyclopropyl, cyclobutyl, phenyl, vinyl, dimethylvinyl, hydroxycyclopropyl, furanyl and tetrahydrofuranyl; R4 is selected from hydrogen, hydroxy, amino, (C1-C4) alkoxy, (C1-C20) alkyl and (C1-C20) alkyl substituted with hydroxy or carbonyl; R19 is hydrogen or (C1-C6) alkyl; R20 is selected from hydrogen, (C1-C6) alkyl and hydroxyalkyl (C1-C6); R21 is hydrogen; R22 is selected from hydrogen, hydroxy and (C1-C4) alkoxy and -NR13R14; or R21 and R22 together form a carbonyl or vinyl substituent; R13 and R14 are independently selected from hydrogen, (C1-C6) alkyl and (C1-C6) acyl; and R23 is hydrogen, methyl, or R19 and R23 together form a second bond.Compuesto de fórmula:**Fórmula** donde G se selecciona entre CONH2 y CSNH2; Y es un contraión farmacéuticamente aceptable; Q se selecciona entre alquilo y bencilo; R2 y R2a son ambos hidrógeno o R2 y R2a juntos son >;=O; R3 se selecciona entre hidrógeno, ciclopropilo, ciclobutilo, fenilo, vinilo, dimetilvinilo, hidroxiciclopropilo, furanilo y tetrahidrofuranilo; R4 se selecciona entre hidrógeno, hidroxi, amino, alcoxi(C1-C4), alquilo(C1-C20) y alquilo(C1-C20) sustituido con hidroxi o carbonilo; R19 es hidrógeno o alquilo(C1-C6); R20 se selecciona entre hidrógeno, alquilo(C1-C6) e hidroxialquilo(C1-C6); R21 es hidrógeno; R22 se selecciona entre hidrógeno, hidroxi y alcoxi(C1-C4) y -NR13R14; o R21 y R22 juntos forman un sustituyente carbonilo o vinilo; R13 y R14 se seleccionan independientemente entre hidrógeno, alquilo(C1-C6) y acilo(C1-C6); y R23 es hidrógeno, metilo, o R19 y R23 juntos forman un segundo enlace.