Co-crystals of compounds of formula 1 ** Formula ** * (HX) j R2b 1 in which R 1 is C 1-6 alkyl, C 1-6 haloalkyl, C 1-6 haloalkyl, halogen; m is 1, 2 or 3; each of R2a and R2b is independently selected from H, C1-6 alkyl, C1-6 alkenyl, C1-6 alkynyl, C3-6 cycloalkyl, COO-C1-6 alkyl, O-C1-6 alkyl, CONR2b.1R2b. 2, halogen; R2b.1 is H, C1-6 alkyl, C0-4 alkyl-C3-6 cycloalkyl, C1-6 haloalkyl; R2b.2 is H, C1-6 alkyl; or R2b.1 and R2b.2 together are a C3-6 alkylene group that forms a heterocyclic ring with the nitrogen atom, where optionally a carbon atom or the ring is replaced by an oxygen atom; R3 is H, C1-6 alkyl; X is an anion selected from the group consisting of chloride, bromide, iodide, sulfate, phosphate, methanesulfonate, nitrate, maleate, acetate, benzoate, citrate, salicylate, fumarate, tartrate, dibenzoyltartrate, oxalate, succinate, benzoate and p-toluenesulfonate ; j is 0, 0.5, 1, 1.5 or 2; with a co-crystal forming agent selected from the group consisting of orotic acid, hippuric acid, L-pyroglutamic acid, D-pyroglutamic acid, nicotinic acid, L - (+) - ascorbic acid, saccharin, piperazine, acid 3 - hydroxy-2-naphthoic acid, mucic acid (galactaric), pamoic acid (embonic), stearic acid, colic acid, deoxycholic acid, nicotinamide, isonicotinamide, succinamide, uracil, L-lysine, L-proline, D-valine, L- arginine, glycineCo-cristales de compuestos de fórmula 1**Fórmula** * (HX)j R2b 1 en la que R1 es alquilo C1-6, haloalquilo C1-6, O-haloalquilo C1-6, halógeno; m es 1, 2 ó 3; cada uno de R2a y R2b se selecciona independientemente entre H, alquilo C1-6, alquenilo C1-6, alquinilo C1-6, cicloalquilo C3-6, COO-alquilo C1-6, O-alquilo C1-6, CONR2b.1R2b.2, halógeno; R2b.1 es H, alquilo C1-6, alquil C0-4-cicloalquilo C3-6, haloalquilo C1-6; R2b.2 es H, alquilo C1-6; o R2b.1 y R2b.2 juntos son un grupo alquileno C3-6 que forma con el átomo de nitrógeno un anillo heterocíclico, donde opcionalmente un átomo de carbono o el anillo está reemplazado por un átomo de oxígeno; R3