Chiral assay of omeprazole and metabolites and its application to a pharmacokinetics related to CYP2C19 genotypes

Enantioseparation and molecular docking study of selected chiral pharmaceuticals on a commercialized phenylcarbamate-β-cyclodextrin column using polar organic mode

The chiral separation capability of Chiral-CD-Ph column, containing phenylcarbamate-β-cyclodextrin as the chiral selector in polar organic mode was investigated. A total of twenty-five compounds with different structures and acid-base properties were evaluated, and twenty of them were separated using acetonitrile or methanol as eluent. The effects of various chromatographic parameters, such as the type and proportion of organic modifier, flow rate, and column temperature were analyzed in detail in relation to chromatographic performance. A U-shape retention curve was observed when a mixture of acetonitrile and methanol was used as the eluent, indicating different types of interactions in different solvent mixtures. Van 't Hoff analysis was used for calculation of thermodynamic parameters which revealed that the enantioseparation is mainly enthalpy controlled; however, entropic control was also observed. The enantiomer recognition ability at the atomic level was also investigated through a molecular docking study, which revealed surface binding in polar organic mode instead of inclusion complexation. Our work proves that the phenylcarbamate-β-cyclodextrin-based chiral stationary phase can be effectively used in polar organic mode for the chiral separation of structurally diverse compounds. Furthermore, it is important to note that our study demonstrated that surface binding is responsible for the formation of supramolecular complexes in certain cyclodextrin derivatives.

Chiral separation in the class of proton pump inhibitors by chromatographic and electromigration techniques: An overview

Proton pump inhibitors (PPIs) are benzimidazole-derivative chiral sulfoxides, frequently used in the treatment of gastric hyperacidity-related disorders. Due to their stereoselective metabolism, the eutomeric forms of PPIs can present a more advantageous pharmacokinetic profile by comparison with the distomers or racemates. Moreover, two representatives of the class are used in therapy both as racemates and as pure enantiomers (esomeprazole, dexlansoprazole). A relatively large number of enantioseparation methods employed for the stereoselective determination of PPIs from pharmaceutical, biological, and environmental matrices were published in the past three decades. The purpose of the current overview is to provide a systematic survey of the available chiral separation methods published since the introduction of PPIs in the therapy up to the present. Analytical and bioanalytical methods using different chromatographic and electromigration techniques reported for the enantioseparation of omeprazole, lansoprazole, pantoprazole, rabeprazole, ilaprazole, and tenatoprazole are included. The analytical conditions of the presented methods are summarized in three comprehensive tables, while a critical discussion of the applied techniques, possible mechanism of enantiorecognition, and future perspectives on the topic are also presented.

Severe adverse reactions caused by omeprazole: A case report

A 61-year-old female patient was admitted to hospital following development of a whole-body rash for 10 days, diarrhea for 7 days, and unconsciousness and oliguria for 1 day. The patient had developed stomach discomfort following the oral administration of non-steroidal anti-inflammatory drugs, the exact nature of which was unknown, for the treatment of arthritic pain for >1 month. The patient was then prescribed omeprazole enteric-coated tablets (20 mg twice daily) for treatment of this symptom. However, the patient developed a whole-body rash 7 days after administering omeprazole, 10 days prior to admission. This symptom was followed by severe diarrhea with nausea and vomiting after 10 days, then shock. The shock occurred after administering omeprazole for 16 days. The patient developed a whole body rash 7 days after administering omeprazole, then 3 days later (after administering omeprazole for 10 days) severe diarrhea with nausea and vomiting occurred. The shock remained until administering omeprazole on the 16th day, with severe diarrhea with nausea and vomiting occurring 6 days later. The patient's condition did not improve following treatment for allergies, low blood pressure and oliguria in the Intensive Care Unit (ICU) department at Suzhou Municipal Hospital. For further diagnosis and treatment, the patient was admitted to the ICU department of The First Affiliated Hospital of Bengbu Medical College and was given a fluid infusion, antibiotics and phlegm-reducing treatment, a plasma infusion, blood filtration, and anti-diarrheal and anti-allergy treatment. The patient's vital signs were stable, with a normal temperature and hemogram results, and improved kidney function and deflorescence. Genetic screening revealed that the patient poorly metabolized omeprazole. Therefore, severe adverse reactions (allergic shock, rash and diarrhea) experienced by the patient were caused by the accumulation of omeprazole metabolites resulting from its slow metabolism in vivo.

The (R)-omeprazole hydroxylation index reflects CYP2C19 activity in healthy Japanese volunteers

PURPOSE

Omeprazole has (R)- and (S)-enantiomers, which exhibit different pharmacokinetics (PK) among patients with cytochrome P450 (CYP) 2C19 genotype groups. The aim of this study was to investigate whether the 1-point, 4-h postdose (R)-omeprazole hydroxylation index (HI) of racemic omeprazole reflects the three CYP2C19 genotype groups in Japanese individuals.

METHODS

Ninety healthy Japanese individuals were enrolled and classified into the three different CYP2C19 genotype groups: homozygous extensive metabolizers (hmEMs; n = 34), heterozygous EMs (htEMs; n = 44), and poor metabolizers (PMs; n = 12). Blood samples were drawn 4 h after the intake of an oral dose of omeprazole 40 mg, and plasma levels of omeprazole and its metabolites were analyzed by high-performance liquid chromatography (HPLC) using a chiral column.

RESULTS

Mean plasma concentrations of (R)- and (S)-omeprazole in PMs were significantly higher than those in hmEMs and htEMs, and similar results were obtained in the case of omeprazole sulfone. Additionally, there was a significant difference in plasma concentrations of (R)-5-hydroxyomeprazole among CYP2C19 genotype groups, whereas no significant differences were observed in that of (S)-5-hydroxyomeprazole. Similarly, (R)-omeprazole HI in hmEMs, htEMs, and PMs were 5.6, 3.1, and 0.3, respectively, which were significantly different, but no significant difference was present in the (S)-omeprazole HI.

CONCLUSION

Our findings demonstrate that (R)-omeprazole HI correlated better with CYP2C19 genotype groups than racemic-omeprazole HI, and these results may be useful for classification among patients in CYP2C19 genotype groups prior to omeprazole treatment.