Sub-lethal doses of albendazole induce drug metabolizing enzymes and increase albendazole deactivation in Haemonchus contortus adults

Table 2 **Biotransformation of ABZ inH. contortusadults—the metabolites detected by UHPLC-MS/MS**

t_R (min)	Theoretical m/z values of [M+H]⁺ ions	Elemental composition	Description of metabolite formation		Product ions of [M+H]+, m/z	Metabolite designation
t_R (min)	Theoretical m/z values of [M+H]⁺ ions	Elemental composition	Phase I	Phase II	Product ions of [M+H]+, m/z	Metabolite designation
2.0	444.14	C₁₈H₂₅N₃O₈S	S-oxidation	N-glycosidation	282, 240, 208	M1_ABZ
2.5	444.14	C₁₈H₂₅N₃O₈S	S-oxidation	N-glycosidation	282, 240, 208	M2_ABZ
3.4	282.09	C₁₂H₁₅N₃O₃S	S-oxidation	–	240, 208, 191,159	M3_ABZ
4.3	370.14	C₁₆H₂₃N₃O₅S	Hydrolysis	N-glycosidation	208	M4_ABZ
5.2	298.09	C₁₂H₁₅N₃O₄S	2*S-oxidation	–	266, 224, 159	M6_ABZ
5.1	428.15	C₁₈H₂₅N₃O₇S	–	N-glycosidation	266, 234	M7_ABZ
5.1	428.15	C₁₈H₂₅N₃O₇S	+O, hydrolysis	Glycosidation, O-acetylation	208	M11_ABZ
5.3	428.15	C₁₈H₂₅N₃O₇S	+O, hydrolysis	Glycosidation, O-acetylation	208	M12_ABZ
5.6	428.15	C₁₈H₂₅N₃O₇S	+O, hydrolysis	Glycosidation, O-acetylation	208	M13_ABZ
6.1	428.15	C₁₈H₂₅N₃O₇S	+O, hydrolysis	Glycosidation, O-acetylation	208	M10_ABZ
6.1	428.15	C₁₈H₂₅N₃O₇S	–	N-glycosidation	266, 234	M8_ABZ
6.7	428.15	C₁₈H₂₅N₃O₇S	–	N-glycosidation	266, 234	M9_ABZ
7.4	266.10	C₁₂H₁₅N₃O₂S	–	–	234	ABZ (parent drug)

ISSN: 1297-9716