Estimation of nizatidine gastric nitrosatability and product toxicity via an integrated approach combining HILIC, in silico toxicology, and molecular docking

Rania El-Shaheny ^a,b,*, Mohamed Radwan ^c,d,e, Koji Yamada ^f,**, Mahmoud El-Maghrabey ^a,g

a Department of Pharmaceutical Analytical Chemistry, Faculty of Pharmacy, Mansoura University, Mansoura 35516, Egypt

b Department of Hygienic Chemistry and Toxicology, Course of Pharmaceutical Sciences, Graduate School of Biomedical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan

c Department of Drug Discovery, Science Farm Ltd., 1-7-30 Kuhonji, Chuo-ku, Kumamoto 862-0976, Japan

d Department of Bioorganic Medicinal Chemistry, Faculty of Life Sciences, Kumamoto University, 5e1 Oehonmachi, Chuo-ku, Kumamoto 862-0973, Japan

e Chemistry of Natural Compounds Department, Pharmaceutical and Drug Industries Research Division, National

Research Centre, Dokki 12622, Cairo, Egypt

f Medical Plant Laboratory, Course of Pharmaceutical Sciences, Graduate School of Biomedical Sciences, Nagasaki

University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan

g Department of Analytical Chemistry for Pharmaceuticals, Course of Pharmaceutical Sciences, Graduate School of Biomedical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan

The liability of the H2-receptor antagonist nizatidine (NZ) to nitrosation in simulated gastric juice (SGJ) and under WHO-suggested conditions was investigated for the first time. For monitoring the nitrosatability of NZ, a hydrophilic interaction liquid chromatography (HILIC) method was optimized and validated according to FDA guidance. A Cosmosil HILIC® column and a mobile phase composed of acetonitrile: 0.04 M acetate buffer pH 6.0 (92:8, v/v) were used for the separation of NZ and its N-nitroso derivative (NZ-NO) within 6 min with LODs of 0.02 and 0.1 μg/mL, respectively. NZ was found highly susceptible to nitrosation in SGJ reaching 100% nitrosation in 10 min, while only 18% nitrosation was observed after 160 min under the WHO-suggested conditions. The chemical structure of NZ-NO was clarified by ESI+/MS. In silico toxicology study confirmed the mutagenicity and toxicity of NZ-NO. Experiments evidenced that ascorbic acid strongly suppresses the nitrosation of NZ suggesting their co-administration for protection from potential risks. In addition, the impacts of the HILIC method on safety, health, and environment were favorably evaluated by three green analytical chemistry metrics and it was proved that, unlike the popular impression, HILIC methods could be green to the environment.

Keywords: HILIC; In silico toxicity; Nizatidine; Nitrosation; Simulated gastric juice

https://doi.org/10.1016/j.jfda.2019.08.001.

(http://www.sciencedirect.com/science/article/pii/S1021949819300729)