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Ferlini Agne G, Somogyi AA, Sykes B, Knych H, Franklin S. Identification and kinetics of microsomal and recombinant equine liver cytochrome P450 enzymes responsible for in vitro metabolism of omeprazole. Biochem Pharmacol 2023:115635. [PMID: 37285945 DOI: 10.1016/j.bcp.2023.115635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 05/26/2023] [Accepted: 05/31/2023] [Indexed: 06/09/2023]
Abstract
In humans, omeprazole is metabolised by cytochrome P450 (CYP450) CYP2C19 and CYP3A4 with differences in CYP2C19 genotypes leading to variable response to therapy. Despite a wide use of omeprazole in horses with evidence of variable therapeutic efficiency, information regarding enzymatic metabolism is not currently available. This study aims to describe the in vitro kinetics of omeprazole metabolism and determine which enzyme(s) are responsible for omeprazole metabolism in horses. Omeprazole (0-800 uM) was incubated with liver microsomes and a panel of equine recombinant CYP450s (eq-rCYP). Metabolite concentrations were quantified by LC-MS and the kinetics of metabolites' formation were calculated by non-linear regression analysis. The in vitro liver microsomes formed three metabolites (5-hydroxy-omeprazole, 5-O-desmethyl-omeprazole and omeprazole-sulfone). The 5-O-desmesthyl-omeprazole formation was best fitted to a two enzyme Michaelis-Menten (MM) model with the high affinity site Clint double that of the low affinity site. For 5-hydroxy-omeprazole the best fit was to a 1 enzyme MM model with a Clint higher than for 5-O-desmesthyl-omeprazole (0.12 vs 0.09 pmol/min/pmol P450). The formation of omeprazole-sulfone was negligible. Recombinant CYP3A89 and CYP3A97 produced substantial amounts of 5-hydroxy-omeprazole (1551.72 ng/mL and 1665.33 ng/mL, respectively), while 5-O-desmethyl-omeprazole and omeprazole-sulfone were formed to a much lesser extent by multiple eq-rCYP from the CYP2C and CYP3A family. In vitro metabolism of omeprazole in horses is different to that in humans, with major metabolites produced by the CYP3A family. The current study provides the basis for further investigations of CYP450 single nucleotide polymorphisms that could affect omeprazole metabolism and therapeutic efficacy.
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Affiliation(s)
- Gustavo Ferlini Agne
- School of Animal and Veterinary Sciences, University of Adelaide, Roseworthy, South Australia, Australia.
| | - Andrew A Somogyi
- Discipline of Pharmacology, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, South Australia, Australia
| | - Ben Sykes
- School of Veterinary Medicine, Massey University, Palmerston North, NZ
| | - Heather Knych
- K.L. Maddy Equine Analytical Pharmacology Laboratory, School of Veterinary Medicine, University of California-Davis, Davis, CA, USA
| | - Samantha Franklin
- School of Animal and Veterinary Sciences, University of Adelaide, Roseworthy, South Australia, Australia
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Lehman ML, Bass L, Gustafson DL, Rao S, O’Fallon ES. Clinical efficacy, safety and pharmacokinetics of a novel long‐acting intramuscular omeprazole in performance horses with gastric ulcers. EQUINE VET EDUC 2021. [DOI: 10.1111/eve.13546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- M. L. Lehman
- Department of Clinical Sciences Colorado State University College of Veterinary Medicine and Biomedical Sciences Fort Collins Colorado USA
| | - L. Bass
- Department of Clinical Sciences Colorado State University College of Veterinary Medicine and Biomedical Sciences Fort Collins Colorado USA
| | - D. L. Gustafson
- Department of Clinical Sciences Colorado State University College of Veterinary Medicine and Biomedical Sciences Fort Collins Colorado USA
| | - S. Rao
- Department of Clinical Sciences Colorado State University College of Veterinary Medicine and Biomedical Sciences Fort Collins Colorado USA
| | - E. S. O’Fallon
- Department of Clinical Sciences Colorado State University College of Veterinary Medicine and Biomedical Sciences Fort Collins Colorado USA
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Wise JC, Hughes KJ, Edwards S, Jacobson GA, Narkowicz CK, Raidal SL. Pharmacokinetic and pharmacodynamic effects of 2 registered omeprazole preparations and varying dose rates in horses. J Vet Intern Med 2020; 35:620-631. [PMID: 33340169 PMCID: PMC7848319 DOI: 10.1111/jvim.15971] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 11/02/2020] [Accepted: 11/10/2020] [Indexed: 12/02/2022] Open
Abstract
Background Omeprazole preparations vary in bioavailability in horses. Hypothesis/Objectives To characterize the pharmacokinetics and pharmacodynamics of an existing enteric‐coated oral omeprazole paste (REF) and a novel, in‐feed, enteric‐coated dry granule preparation (NOV). Animals Twelve Standardbred/Thoroughbred mares free from clinical disease. Methods A prospective, blinded randomized interventional study was trial, conducted in 3 parts: (a) bioavailability study, (b) dose titration study, and (c) comparative clinical pharmacodynamic study, each using a blocked crossover design. Results Consistent with the larger dose administered, Cmax (median, 1032 ng/mL; range, 576‐1766) and AUC0‐24 (median, 63.9 μg/mL*min; range, 42.4‐152.4) were greater after single oral administration of NOV than REF (282.7 ng/mL; range, 94.8‐390.2, and 319 23.8 μg/mL*min; range, 8.2‐42.3, respectively; both P = .004). No differences were observed between products for absolute oral bioavailability (NOV 55% range, 15‐88; REF 17% range, 10‐77; P = .25). Treatment with both preparations was associated with reduced gastric squamous ulcer scores and increased pH of gastric fluid. Bioequivalence was demonstrated for pharmacodynamic measures with the exception of % time pH <4, despite differences in dose rate and subsequent plasma omeprazole concentrations. Conclusions and Clinical Importance The findings of this study indicate that the NOV product would be a suitable alternative to the reference product, and confirm that plasma concentrations of omeprazole and omeprazole dose do not predict drug pharmacodynamics in horses.
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Affiliation(s)
- Jessica C Wise
- School of Animal and Veterinary Sciences, Charles Sturt University, Wagga Wagga, New South Wales, Australia
| | - Kristopher J Hughes
- School of Animal and Veterinary Sciences, Charles Sturt University, Wagga Wagga, New South Wales, Australia
| | - Scott Edwards
- School of Animal and Veterinary Sciences, Charles Sturt University, Wagga Wagga, New South Wales, Australia
| | - Glenn A Jacobson
- School of Pharmacy and Pharmacology, University of Tasmania, Hobart, Tasmania, Australia
| | - Christian K Narkowicz
- School of Pharmacy and Pharmacology, University of Tasmania, Hobart, Tasmania, Australia
| | - Sharanne L Raidal
- School of Animal and Veterinary Sciences, Charles Sturt University, Wagga Wagga, New South Wales, Australia
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The Effect of a Seaweed-Derived Calcium Supplement on Gastric Juice pH in the Horse. J Equine Vet Sci 2020; 95:103265. [PMID: 33276919 DOI: 10.1016/j.jevs.2020.103265] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 08/14/2020] [Accepted: 09/09/2020] [Indexed: 11/22/2022]
Abstract
Low gastric pH for extended periods of time can increase the risk of gastric ulceration in horses. Therefore, nutritional interventions that buffer stomach acid may be helpful to decrease ulcer risk. The objective of this trial was to evaluate whether the incorporation of calcified Lithothamnion corallioides and Phymatolithon calcareum (Calmin; Celtic Sea Minerals, Cork, Ireland) into an equine ration would buffer equine gastric juice. Nine mature, Thoroughbred-cross horses, including 6 geldings and 3 mares (524 ± 49 kg) were housed in stalls and fed 2 kg/day of a texturized concentrate (Purina Omolene 100) and 1.5% BW grass hay/day. On testing days 0, 7, and 14, the horses received one of three pelleted dietary treatments (CON, MIN1 ×, MIN2 ×) in a randomized, crossover design. CON contained no added Calmin, MIN1 × provided Calmin at a 1 × concentration, and MIN2 × provided a 2 × dose. All horses underwent gastroscopy (Karl Storz, El Segundo, CA) prior to feeding the treatments, and at 2 and 4 hours postfeeding. Gastric juice was aspirated and pH measured using a benchtop pH meter (ThermoOrion pH Meter Model 410A). Overall, there was a significant time effect (P < .0001) with an increase in gastric juice pH from time 0 (2.31 ± 0.58) to 2 hours (5.52 ± 0.48) and 4 hours (3.59 ± 0.48). Gastric juice pH at 2 hours was higher (P = .0122) in MIN1 × (5.92 ± 0.58) and MIN2 × (5.92 ± 0.57) than CON (5.08 ± 0.58). These results demonstrate that adding Calmin to a meal increases buffering capacity at 2 hours postfeeding.
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Wise JC, Raidal SL, Wilkes EJA, Hughes KJ. Intragastric pH of foals admitted to the intensive care unit. J Vet Intern Med 2020; 34:2719-2726. [PMID: 32990384 PMCID: PMC7694801 DOI: 10.1111/jvim.15888] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 08/11/2020] [Accepted: 08/18/2020] [Indexed: 11/29/2022] Open
Abstract
Background Intragastric pH profiles of neonatal foals admitted to the intensive care unit (ICU) remain poorly characterized. Hypothesis/Objectives To determine intragastric pH profiles and clinical parameters associated with intragastric pH in foals admitted to the ICU. Animals Forty‐two neonatal foals admitted to the ICU and requiring placement of an indwelling nasogastric tube for nutritional management were included. Methods Intragastric pH was measured for 24 hours from the time of admission. Mean pH, % time pH <4, and % time pH >4 were determined for each foal. History, clinical findings, and clinicopathological data recorded at the time of presentation were collected. Results The mean pH of included foals was 5.5 ± 1.8. The median % time pH <4 was 6.3% (range: 0‐99). A history of placentitis was associated with greater mean pH (median 5.3 (range: 0.9‐7.8) versus median 7.2 (5.9‐11.3); P = .002) and less % time pH <4 (median 13 (0‐99.6) versus median 0.1 (0‐7.2); P = .01). Foals with diarrhea had a greater % time pH <4 (median 4.6% (0‐99) versus median 28.8% (1.4‐57.48); P = .02). Foals with a pH >4 for >50% recording time had a lower PaO2 (mean difference 25.0 mm Hg; 95% confidence interval [CI], 14.4‐35.6; P = .03) and higher PaCO2 (mean difference 14.9 mm Hg; 95% CI, 4.7‐25.2; P = .02). Surviving foals had a lower mean median hourly pH (P = .02). Conclusions and Clinical Importance Intragastric pH profiles were unpredictable and mostly >4 for >80% of the recording time. This study does not support the indiscriminate administration of acid suppressive treatment.
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Affiliation(s)
- Jessica C Wise
- Veterinary Clinical Centre, School of Animal and Veterinary Science, Charles Sturt University, Wagga Wagga, New South Wales, Australia
| | - Sharanne L Raidal
- Veterinary Clinical Centre, School of Animal and Veterinary Science, Charles Sturt University, Wagga Wagga, New South Wales, Australia
| | - Edwina J A Wilkes
- Veterinary Clinical Centre, School of Animal and Veterinary Science, Charles Sturt University, Wagga Wagga, New South Wales, Australia
| | - Kristopher J Hughes
- Veterinary Clinical Centre, School of Animal and Veterinary Science, Charles Sturt University, Wagga Wagga, New South Wales, Australia
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Varley G, Bowen IM, Habershon‐Butcher JL, Nicholls V, Hallowell GD. Misoprostol is superior to combined omeprazole‐sucralfate for the treatment of equine gastric glandular disease. Equine Vet J 2019; 51:575-580. [DOI: 10.1111/evj.13087] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 02/23/2019] [Indexed: 12/20/2022]
Affiliation(s)
| | - I. M. Bowen
- School of Veterinary Medicine and Science University of Nottingham Loughborough UK
| | | | - V. Nicholls
- School of Veterinary Science University of Liverpool Leahurst UK
| | - G. D. Hallowell
- School of Veterinary Medicine and Science University of Nottingham Loughborough UK
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Sykes BW. Courses for horses: Rethinking the use of proton pump inhibitors in the treatment of equine gastric ulcer syndrome. EQUINE VET EDUC 2018. [DOI: 10.1111/eve.12894] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- B. W. Sykes
- School of Veterinary Sciences The University of Queensland Gatton Queensland Australia
- Bova Compounding Caringbah New South Wales Australia
- Luoda Pharma Pty Ltd Caringbah New South Wales Australia
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Huxford KE, Dart AJ, Perkins NR, Bell R, Jeffcott LB. A pilot study comparing the effect of orally administered esomeprazole and omeprazole on gastric fluid pH in horses. N Z Vet J 2017; 65:318-321. [PMID: 28738738 DOI: 10.1080/00480169.2017.1359125] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
AIMS To compare the efficacy of an enteric coated esomeprazole paste with an enteric coated omeprazole paste to increase gastric pH after oral administration in horses. METHODS Nine adult Standardbred horses were randomly assigned to three groups, each containing three horses, for a study comprising three phases of 10 days, with an 18-day washout period between each phase. In each phase, three horses received either 0.5 mg/kg esomeprazole, 1 mg/kg omeprazole or a placebo, as an oral paste, once daily for 10 days (Days 0-9). Over the course of study all horses received all three treatments. Gastric fluid samples were collected using a gastroscope on Days 1, 3, 5, 8 and 10, with food and water withheld for 16 hours prior to collection of samples. The pH of all samples was measured immediately after collection. RESULTS Mean pH (3.38; SD 1.75) of the gastric fluid samples in the horses that received the placebo was lower than in the horses that received esomeprazole (6.28; SD 1.75) or omeprazole (6.13; SD 1.75) (p<0.001). There was no difference in the mean pH between horses receiving esomeprazole and those receiving omeprazole (p=0.56). CONCLUSIONS AND CLINICAL RELEVANCE Under these study conditions, esomeprazole paste was equally as effective as omeprazole paste in increasing gastric pH in horses. Enteric coated esomeprazole, may be a therapeutic alternative to omeprazole for the prevention of gastric ulcers in horses.
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Affiliation(s)
- K E Huxford
- a University Veterinary Teaching Hospital Camden , University of Sydney , Camden , NSW 2567 , Australia
| | - A J Dart
- a University Veterinary Teaching Hospital Camden , University of Sydney , Camden , NSW 2567 , Australia
| | - N R Perkins
- b School of Veterinary Science , University of Queensland , Gatton , QLD 4343 , Australia
| | - R Bell
- a University Veterinary Teaching Hospital Camden , University of Sydney , Camden , NSW 2567 , Australia
| | - L B Jeffcott
- a University Veterinary Teaching Hospital Camden , University of Sydney , Camden , NSW 2567 , Australia
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Bush J, van den Boom R, Franklin S. Comparison of aloe vera and omeprazole in the treatment of equine gastric ulcer syndrome. Equine Vet J 2017; 50:34-40. [DOI: 10.1111/evj.12706] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 05/16/2017] [Indexed: 11/30/2022]
Affiliation(s)
- J. Bush
- School of Animal and Veterinary Science; Adelaide South Australia Australia
| | - R. van den Boom
- School of Animal and Veterinary Science; Adelaide South Australia Australia
| | - S. Franklin
- School of Animal and Veterinary Science; Adelaide South Australia Australia
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Sykes BW, Kathawala K, Song Y, Garg S, Page SW, Underwood C, Mills PC. Preliminary investigations into a novel, long-acting, injectable, intramuscular formulation of omeprazole in the horse. Equine Vet J 2017; 49:795-801. [DOI: 10.1111/evj.12688] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 04/04/2017] [Indexed: 12/11/2022]
Affiliation(s)
- B. W. Sykes
- School of Veterinary Science; University of Queensland; Gatton Queensland Australia
- Luoda Pharma Pty Ltd; Caringbah New South Wales Australia
| | - K. Kathawala
- Centre for Pharmaceutical Innovation and Development; University of South Australia; Adelaide South Australia Australia
| | - Y. Song
- Centre for Pharmaceutical Innovation and Development; University of South Australia; Adelaide South Australia Australia
| | - S. Garg
- Centre for Pharmaceutical Innovation and Development; University of South Australia; Adelaide South Australia Australia
| | - S. W. Page
- Luoda Pharma Pty Ltd; Caringbah New South Wales Australia
| | - C. Underwood
- School of Veterinary Science; University of Queensland; Gatton Queensland Australia
| | - P. C. Mills
- School of Veterinary Science; University of Queensland; Gatton Queensland Australia
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Sykes BW, Underwood C, Mills PC. The effects of dose and diet on the pharmacodynamics of esomeprazole in the horse. Equine Vet J 2017; 49:637-642. [PMID: 28117490 DOI: 10.1111/evj.12670] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Accepted: 01/18/2017] [Indexed: 12/13/2022]
Abstract
BACKGROUND Esomeprazole warrants further investigation as a treatment for equine gastric ulcer syndrome. OBJECTIVES To investigate the duration of intraday acid suppression achieved with two doses of esomeprazole under two dietary conditions. STUDY DESIGN A four way crossover design. METHODS Six adult Thoroughbreds instrumented with percutaneous gastrotomy tubes were used. Intragastric pH was measured for continuous 23 h periods (08.00-07.00 h) for 6 consecutive days (Days 0-5). Baseline data was recorded on Day 0 and esomeprazole was administered on Days 1-5. Two doses (0.5 and 2.0 mg/kg bwt/day per os once daily) and two diets (a high grain/low fibre (HG/LF) and ad libitum hay (HAY) diet) were studied. Data for the percentage of time pH was above 4 (%tpH>4) and median intraday pH was reported for two measurement points and analysed using generalised estimating equations. RESULTS An inconsistent effect of both diet and dose was evident with mean %tpH>4 and mean of the median intraday pHs typically higher at the 2.0 mg/kg bwt dose and in HG/LF diet. A cumulative effect of dosing was present with the magnitude of acid suppression observed on Day 5 consistently higher than that observed on Day 1. The magnitude of acid suppression, at measurement point 1, compared favourably with previous reports on omeprazole and exceeded human therapeutic breakpoints for the 0.5 mg/kg bwt dose in the HG/LF diet and 2.0 mg/kg bwt dose in the HAY diet. MAIN LIMITATIONS Instrumentation may have modified gastric function and horses were not fasted or exercised. CONCLUSIONS The findings of the present study suggested that both dose and diet affect the response to esomeprazole in the horse and that a cumulative effect is present over the first 5 days of treatment. Further investigation into the clinical efficacy of esomeprazole and trials directly comparing esomeprazole and omeprazole appear to be warranted.
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Affiliation(s)
- B W Sykes
- School of Veterinary Science, The University of Queensland, Gatton, Queensland, Australia.,Bova Compounding, Caringbah, New South Wales, Australia
| | - C Underwood
- School of Veterinary Science, The University of Queensland, Gatton, Queensland, Australia
| | - P C Mills
- School of Veterinary Science, The University of Queensland, Gatton, Queensland, Australia
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Sykes BW, Underwood C, Greer R, McGowan CM, Mills PC. The effects of dose and diet on the pharmacodynamics of omeprazole in the horse. Equine Vet J 2016; 49:525-531. [DOI: 10.1111/evj.12630] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Accepted: 08/19/2016] [Indexed: 12/13/2022]
Affiliation(s)
- B. W. Sykes
- School of Veterinary Science; The University of Queensland; Gatton Australia
| | - C. Underwood
- School of Veterinary Science; The University of Queensland; Gatton Australia
| | - R. Greer
- School of Veterinary Science; The University of Queensland; Gatton Australia
| | - C. M. McGowan
- Institute of Ageing and Chronic Disease; University of Liverpool; Liverpool UK
| | - P. C. Mills
- School of Veterinary Science; The University of Queensland; Gatton Australia
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