Identification of IY81149 and its metabolites in the rat plasma using the on-line HPLC/ESI mass spectrometry

Identification of the New In Vivo Metabolites of Ilaprazole in Rat Plasma after Oral Administration by LC-MS: In Silico Prediction of the H+/K+-ATPase Inhibitor

Ilaprazole is a proton pump inhibitor used to treat digestive diseases. In this study, blood samples were collected after oral administration of ilaprazole and prepared by liquid–liquid extraction. The metabolites of ilaprazole were detected by liquid chromatography–high-resolution mass spectrometry (LC-HRMS) and LC-MSⁿ. A total of twelve in vivo metabolites were detected in rat plasma and six new metabolites of ilaprazole, including one reductive metabolite with sulfide (M3), two hydroxylated metabolites with sulfoxide (M7 and M8), and three oxidative metabolites with sulfone (M9, M11, and M12), were identified. The possible metabolic pathways of ilaprazole and the fragmentation behaviors of its metabolites were elucidated. The result of the in silico prediction indicates that all the new metabolites showed the potential ability to inhibit H⁺/K⁺-ATPase activity.

Biotransformation of Ilaprazole in Human Liver Microsomes and Human: Role of CYP3A4 in Ilaprazole Clearance and Drug-Drug Interaction

Ilaprazole is a new proton pump inhibitor and is currently marketed in China and South Korea for the treatment of gastric and duodenal ulcer. Ilaprazole has a favorable long half-life and minimal pharmacokinetic variability associated with CYP2C19 polymorphism. Sulfoxide oxidation of ilaprazole is catalyzed mainly by CYP3A4. Thus, it has been widely accepted that CYP3A4 plays a major role in the clearance of ilaprazole in humans. However, absorption, distribution, metabolism, and excretion data of radiolabeled ilaprazole in humans are not available. The primary goal of this study was to determine if sulfoxide oxidation is a major metabolic pathway of ilaprazole in humans. Metabolite profiles of ilaprazole, ilaprazole sulfide, and ilaprazole sulfone in human liver microsomes (HLMs) were characterized and quantitively analyzed by liquid chromatography (LC)/UV/high-resolution mass spectrometry (HRMS). Moreover, metabolites of ilaprazole in human urine and feces were detected and identified by LC-HRMS. The results revealed that sulfoxide reduction to ilaprazole sulfide rather than sulfoxide oxidation was the major biotransformation pathway in HLMs. Sulfoxide reduction also occurred in HLMs without NADPH or in deactivated HLMs. Ilaprazole sulfide and its multiple oxidative metabolites were major drug-related components in human urine and feces, where there were no ilaprazole sulfone and its metabolites. A small amount of the parent drug was found in feces. Thus, we propose that nonenzymatic sulfoxide reduction rather than CYP3A4-medidated sulfoxide oxidation is the major metabolic clearance pathway of ilaprazole in humans. Consequently, it is predicted that ilaprazole has no significant drug-drug interaction via CYP3A4 inhibition or induction by a coadministered drug.

Pharmacokinetic drug interaction and safety after coadministration of clarithromycin, amoxicillin, and ilaprazole: a randomised, open-label, one-way crossover, two parallel sequences study

Purpose

Ilaprazole, the latest proton pump inhibitor, can be used with clarithromycin and amoxicillin as a triple therapy regimen for eradicating Helicobacter pylori. The aim of this study was to evaluate pharmacokinetic drug interactions and safety profiles after coadministration of clarithromycin, amoxicillin, and ilaprazole.

Methods

A randomised, open-label, one-way crossover, two parallel sequences study was conducted in 32 healthy subjects. In part 1, the subjects received a single dose of ilaprazole 10 mg in period 1 and clarithromycin 500 mg and amoxicillin 1000 mg twice daily for 6 days in period 2. In part 2, the subjects received clarithromycin 500 mg and amoxicillin 1000 mg once in period 1 and ilaprazole 10 mg twice daily for 6 days in period 2. In both sequences, the three drugs were coadministrated once on day 5 in period 2. Pharmacokinetic evaluations of ilaprazole (part 1), and clarithromycin and amoxicillin (part 2) were conducted.

Results

Twenty-eight subjects completed the study. For ilaprazole, the peak concentration (C_max) slightly decreased from 479 (ilaprazole alone) to 446 ng/mL (triple therapy) [Geometric least square mean ratio (90% confidence interval), 0.93 (0.70–1.22)]. The area under the concentration-time curve from 0 h to the last measurable concentration (AUC_last) slightly increased from 3301 to 3538 μg·h/mL [1.07 (0.85–1.35)]. For clarithromycin, the C_max slightly decreased from 1.87 to 1.72 μg/mL [0.90 (0.70–1.15)], and AUC_last slightly increased from 14.6 to 16.5 μg·h/mL [1.09 (0.87–1.37)]. For amoxicillin, the C_max slightly decreased from 9.37 to 8.14 μg/mL [0.86 (0.74–1.01)], and AUC_last slightly decreased from 27.9 to 26.7 μg·h/mL [0.98 (0.83–1.16)]. These changes in the PK parameters of each drug were not statistically significant.

Conclusions

The coadministration of ilaprazole, clarithromycin, and amoxicillin was tolerable and did not cause a significant PK drug interaction. Thus, a triple therapy regimen comprising ilaprazole, clarithromycin, and amoxicillin may be an option for the eradication of H. pylori.

Clinicaltrials.govnumber: NCT02998437.

Electronic supplementary material

The online version of this article (10.1007/s00228-018-2489-2) contains supplementary material, which is available to authorized users.

Pharmacokinetics and pharmacodynamics of intravenous ilaprazole in healthy subjects after single ascending doses

1. Ilaprazole is a novel proton pump inhibitor and this is the first study to investigate the pharmacokinetics, pharmacodynamics and safety of intravenous ilaprazole in healthy volunteers. 2. In this open-label, single-dose, randomized and four-period crossover study, 16 healthy Chinese subjects received ilaprazole 5, 10 or 20 mg intravenously, or 10 mg orally. Serial blood and urine samples were collected and intragastric pH was recorded within 24 h. The percentage time of intragastric pH > 6 was the major index. Safety was assessed throughout the study. 3. Plasma exposure of intravenous ilaprazole increased proportionally over the dose of 5-20 mg. Clearance and volume of distribution were independent of dose. Ilaprazole was not eliminated through urine and the absolute bioavailability was 55.2%. For the intravenous dose of 5, 10, 20 mg, and oral dose of 10 mg, the mean percentages time of intragastric pH > 6 were 47.3%, 52.8%, 68.2% and 47.5%, respectively. 4. Ilaprazole showed linear pharmacokinetics over the dose of 5-20 mg. Intravenous ilaprazole provided rapid onset of action and the potency of effect were exhibited in a dose-dependent manner. Intravenous ilaprazole was safe and well tolerated except for elevated activated partial thromboplastin time (APTT) and prothrombin time (PT).

The pharmacokinetics of ilaprazole for gastro-esophageal reflux treatment

INTRODUCTION

Approximately 20% of the Western population is affected by gastro-esophageal reflux disease (GERD). To date, proton pump inhibitors (PPIs) represent the mainstay of GERD medical treatment. However, despite their undoubted benefit, about 40% of GERD patients display an inadequate response to these drugs. Recently, a new PPI, ilaprazole , at oral doses of 10 mg has shown higher suppression of gastric acid secretion, more prolonged plasma half-life, and similar safety compared to 20 mg omeprazole.

AREAS COVERED

This review provides an update on the following points: pharmacokinetic profile and metabolism of ilaprazole in relation to its pharmacodynamic properties; comparative data on the pharmacokinetics and pharmacodynamics of ilaprazole with currently available PPIs; and implications for studies on the therapeutic efficacy of ilaprazole in GERD.

EXPERT OPINION

Different studies show that ilaprazole, a benzimidazole derivative, has an extended plasma half-life in comparison with all other approved PPIs. In addition, ilaprazole metabolism is not significantly influenced by CYP2C19, compared to the available PPIs. Furthermore, the pharmacological characteristics of ilaprazole confer theoretical advantages that are expected to translate into an improved acid control, particularly at night time. However, studies comparing the clinical pharmacokinetics and pharmacodynamics of ilaprazole with those of second-generation PPIs are insufficient. Moreover, further investigations assessing the efficacy of ilaprazole in the management of GERD are required. In healthy volunteers, as well as in patients with gastric or duodenal ulcers, ilaprazole has not shown clinically relevant changes in hematology and biochemistry testing, nor significant treatment-related adverse symptoms.

Ilaprazole, a new proton pump inhibitor, is primarily metabolized to ilaprazole sulfone by CYP3A4 and 3A5

Ilaprazole is a new proton pump inhibitor, designed for treatment of gastric ulcers, and developed by Il-Yang Pharmaceutical Co (Seoul, Korea). It is extensively metabolised to the major metabolite ilaprazole sulfone. In the present study, several in vitro approaches were used to identify the cytochrome P450 (CYP) enzymes responsible for ilaprazole sulfone formation. Concentrations of ilaprazole sulfone were determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Incubation of ilaprazole with cDNA-expressed recombinant CYPs indicated that CYP3A was the major enzyme that catalyses ilaprozole to ilaprazole sulfone. This reaction was inhibited significantly by ketoconazole, a CYP3A inhibitor, and azamulin, a mechanism-based inhibitor of CYP3A, while no substantial effect was observed using selective inhibitors for eight other P450s (CYP1A2, CYP2A6, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, and CYP2E1). In addition, the formation of ilaprazole sulfone correlated well with CYP3A-catalysed testosterone 6β-hydroxylation and midazolam 1'-hydroxylation in 20 different human liver microsome panels. The intrinsic clearance of the formation of ilaprazole sulfone by CYP3A4 was 16-fold higher than that by CYP3A5. Collectively, these results indicate that the formation of the major metabolite of ilaprazole, ilaprazole sulfone, is predominantly catalysed by CYP3A4/5.

Investigation on the interaction between ilaprazole and bovine serum albumin without or with different C-ring flavonoids from the viewpoint of food-drug interference

The interaction between ilaprazole and bovine serum albumin (BSA) has been investigated in the absence and presence of four popular flavonoids with different C-ring structures, quercetin, luteolin, taxifolin, and (+)-catechin, by means of fluorescence spectroscopy. The results indicated that ilaprazole had a strong ability to quench the intrinsic fluorescence of BSA, and site marker competitive experiments indicated that the binding of ilaprazole to BSA primarily took place in subdomain IIA. The quenching process of ilaprazole with BSA was easily affected by flavonoids,; however, they did not change the quchenching mechanism of ilaprazole with BSA, whereas all of the fluorescence quenching was initiated by a static quenching procedure combining with nonradiative energy transfer. The presence of flavonoids decreased the quenching constants of ilaprazole with BSA from 2.2 to 23.7% and decreased the binding constants from 73.7 to 98.3%, which depended on the different flavonoids' structures. The decreased binding constants and unchangeable spatial distance of ilaprazole with BSA by the introduction of quercetin, luteolin, and taxifolin may result from the competition of flavonoids and ilaprazole binding to BSA, whereas in the presence of (+)-catichin, decreased binding constants and increased spatial distance possibly resulted from the formation of a ternary ilaprazole-BSA-(+)-catechin complex. All of these results may have relevant consequences in rationalizing the interferences of common food to gastric ulcer treatments.

Effect of CYP2C19 genetic polymorphism on pharmacokinetics and pharmacodynamics of a new proton pump inhibitor, ilaprazole

It is well known that the CYP2C19 genetic polymorphism influences the pharmacokinetics and pharmacodynamics of proton pump inhibitors (PPIs), but no report has addressed the effects on ilaprazole, a newly developed PPI. To investigate the effects of the CYP2C19 genetic polymorphism on the disposition and pharmacodynamics of ilaprazole, multiple doses of once-daily 10 mg ilaprazole were repeatedly administered for 7 days to 27 healthy Korean participants, comprising 9 homozygous CYP2C19 extensive metabolizers (homo EMs), 10 heterozygous EMs (hetero EMs), and 8 homozygous poor metabolizers (PMs). The plasma concentration and pharmacodynamic response were measured in the last dose interval. Each genotype group was matched for gender and thus was composed of 4 male and 4 female participants when the analysis was conducted. The pharmacokinetic parameters estimated from the plasma concentrations of ilaprazole and its metabolite ilaprazole sulfone, the serum gastrin level, and the 24-hour intragastric pH were compared among the CYP2C19 genotype groups. No statistically significant differences in the maximum plasma concentration at steady state(C(ss,max)) and the area under the concentration-time curve from zero to 24 hours (AUC(τ)) of ilaprazole and ilaprazole sulfone were observed among the homo EM, hetero EM, and PM CYP2C19 genotypes. In addition, the mean 24-hour intragastric pH, the percentage of time at pH >4, and the AUC(τ) of serum gastrin showed no significant differences among the CYP2C19 genotype groups. The data suggests that the pharmacokinetics and pharmacodynamics of ilaprazole are not significantly influenced by the CYP2C19 genetic polymorphism in healthy participants.

An improved LC-MS/MS method for quantitative determination of ilaprazole and its metabolites in human plasma and its application to a pharmacokinetic study

AIM

To improve and validate an analytical method based on liquid chromatography and electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) for the quantitative measurement of ilaprazole and its two metablites in human plasma.

METHODS

Separation of analytes and the internal standard (IS), omeprazole, was performed on a Thermo HyPURITY C18 column (150x2.1 mm, 5 microm) with a mobile phase consisting of 10 mmol/L ammonium formate water-acetonitrile solution (50:50, v/v) at a flow rate of 0.25 mL/min. The API4000 triple quadruple mass spectrometer was operated in multiple reactions monitoring mode via positive electrospray ionization interface using the transition m/z 367.2 --> m/z184.0 for ilaprazole, m/z 383.3 --> m/z 184.1 for ilaprazole sulfone, m/z 351.2 --> m/z 168.1 for ilaprazole thiol ether and m/z 346.2 --> m/z 198.0 for omeprazole.

RESULTS

The method was linear over the concentration range of 0.23-2400.00 ng/mL for ilaprazole, 0.05-105.00 ng/mL for ilaprazole thiol ether and 0.06-45.00 ng/mL for ilaprazole sulfone. The intra- and inter-day precisions were all less than 15% in terms of relative standard deviation (RSD), and the accuracy was within 15% in terms of relative error (RE) for ilaprazole, ilaprazole sulfone and ilaprazole thiol ether. The lower limit of quantification (LLOQ) was identifiable and reproducible at 0.23, 0.05 and 0.06 ng/mL with acceptable precision and accuracy for ilaprazole, ilaprazole sulfone and ilaprazole thiol ether, respectively.

CONCLUSION

The validated method offered sensitivity and a wide linear concentration range. This method was successfully applied for the evaluation of the pharmacokinetics of ilaprazole and its two metabolites after single oral doses of 5 mg ilaprazole to 12 healthy Chinese volunteers.

An improved LC-MS/MS method for quantitative determination of ilaprazole and its metabolites in human plasma and its application to a pharmacokinetic study

AIM

To improve and validate an analytical method based on liquid chromatography and electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) for the quantitative measurement of ilaprazole and its two metablites in human plasma.

METHODS

Separation of analytes and the internal standard (IS), omeprazole, was performed on a Thermo HyPURITY C18 column (150x2.1 mm, 5 microm) with a mobile phase consisting of 10 mmol/L ammonium formate water-acetonitrile solution (50:50, v/v) at a flow rate of 0.25 mL/min. The API4000 triple quadruple mass spectrometer was operated in multiple reactions monitoring mode via positive electrospray ionization interface using the transition m/z 367.2 --> m/z184.0 for ilaprazole, m/z 383.3 --> m/z 184.1 for ilaprazole sulfone, m/z 351.2 --> m/z 168.1 for ilaprazole thiol ether and m/z 346.2 --> m/z 198.0 for omeprazole.

RESULTS

The method was linear over the concentration range of 0.23-2400.00 ng/mL for ilaprazole, 0.05-105.00 ng/mL for ilaprazole thiol ether and 0.06-45.00 ng/mL for ilaprazole sulfone. The intra- and inter-day precisions were all less than 15% in terms of relative standard deviation (RSD), and the accuracy was within 15% in terms of relative error (RE) for ilaprazole, ilaprazole sulfone and ilaprazole thiol ether. The lower limit of quantification (LLOQ) was identifiable and reproducible at 0.23, 0.05 and 0.06 ng/mL with acceptable precision and accuracy for ilaprazole, ilaprazole sulfone and ilaprazole thiol ether, respectively.

CONCLUSION

The validated method offered sensitivity and a wide linear concentration range. This method was successfully applied for the evaluation of the pharmacokinetics of ilaprazole and its two metabolites after single oral doses of 5 mg ilaprazole to 12 healthy Chinese volunteers.

Pharmacokinetics of the new proton pump inhibitor ilaprazole in Chinese healthy subjects in relation to CYP3A5 and CYP2C19 genotypes

BACKGROUND

PPIs are widely used in peptic diseases, and this paper is to investigate the kinetic characteristics of a new PPI ilaprazole in Chinese healthy subjects and the association with CYP3A5 and CYP2C19 polymorphisms.

METHODS

21 subjects were selected and treated with 10mg ilaprazole according to their CYP3A5*3 genotypes (including 7 of CYP3A5*1/*1, 7 of *1/*3, and 7 of *3/*3). The plasma concentrations of ilaprazole and its metabolites were monitored by LC-MS/MS method.

RESULTS

The C(max), AUC((0-6)), AUC((0-48)) and AUC((0-infinity)) of ilaprazole were all significantly different across the 3 CYP3A5 genotypes (including 4 of CYP3A5*1/*1, 4 of *1/*3, 3 of *3/*3; P<0.05) in CYP2C19 wild-type subjects (CYP2C19 wt/wts), similar variety of C(max) and AUC((0-6)) among CYP3A5 genotypes (including 3 of CYP3A5*1/*1, 3 of *1/*3, 4 of *3/*3; P<0.05) were also observed in CYP2C19 heterozygous subjects (CYP2C19 wt/mts). The sulfoxidation metabolic index (measure of collective CYP3A activity) indicates that the CYP3A5*1/*1, (high-expressers), *1/*3, (low-expressers), and *3/*3 (no-expressers) groups have medium, lowest and highest activities on ilaprazole metabolism, inconsistent with genotype-based CYP3A5 enzymatic activity. Further analysis showed no correlation between ilaprazole metabolism and CYP2C19 genotypes, evidenced by that the AUC((0-infinity)) of ilaprazole from either CYP3A5*1/*1 or CYP3A5*1/*3 groups was much higher in CYP2C19 wt/wts (n=4) than that in CYP2C19 wt/mts (n=3) (P<0.001), but the C(max) and AUC((0-6)) of ilaprazole from CYP3A5*3/*3 groups, were significantly lower in CYP2C19 wt/wts (n=3) compared to CYP2C19 wt/mts (n=4) (P<0.01).

CONCLUSIONS

There was no demonstrated relationship between ilaprazole metabolism and CYP3A5 polymorphisms.

Comparison of IY81149 with omeprazole in rat reflux oesophagitis

1. This study was aimed at evaluating the effects of IY81149[2-[[(4methoxy-3-methyl)-2-pyridinyl]methylsulfinyl]-5-(1H-pyrrol-1-yl)-1H-benzimidazole], a new proton pump inhibitor, on the development of the surgically induced reflux oesophagitis, on gastric secretion and on lipid peroxidation which is a marker of oxidative stress. Omeprazole was used as a reference drug. We furthermore investigated the influence of quercetin and desferrioxamine (DFO) on the development of the surgically induced reflux oesophagitis in rats on gastric secretion and on lipid peroxidation. 2. IY81149 and omeprazole significantly prevented the development of reflux oesophagitis and gastric secretion in a dose-dependent manner. The ED50 values of IY81149 for inhibition of oesophagitis and volume of gastric secretion were lower than of omeprazole (5.7 vs. 14.2 micromol, 15.3 vs. 24.0 micromol, respectively). IY81149 was also more potent in the acid output inhibition with an ED50 of 6.8 micromol compared with 20.8 micromol of omeprazole. 3. Malonyldialdehyde (MDA) content, the end product of lipid peroxidation, increased significantly in the oesophageal mucosa after the induction of reflux oesophagitis. IY81149 and omeprazole significantly and dose-dependently prevented lipid peroxidation. Quercetin (200 mg kg-1, p.o.) and DFO (800 mg kg-1, i.d.) significantly prevented the development of reflux oesophagitis and inhibited the lipid peroxidation independent of their actions on gastric secretion. 4. This result suggests that IY81149 is comparable with omeprazole in the treatment of reflux oesophagitis.