title: Preliminary investigations into a novel, long-acting, injectable, intramuscular formulation of omeprazole in the horse.
abstract: BACKGROUND
  Pilot investigations have suggested that a novel, long-acting, injectable i.m. formulation of omeprazole (LA-OMEP) can induce acid suppression for up to 7 days following a single injection.
  
  
  OBJECTIVE
  To investigate the pharmacodynamics and assess the clinical efficacy of the LA-OMEP formulation.
  
  
  METHODS
  Part A comprised a pharmacodynamic study. Part B consisted of a pilot clinical trial.
  
  
  METHODS
  Part A enrolled six adult Thoroughbred horses with percutaneous gastrotomy tubes. Intragastric pH was measured for continuous 23-h periods (08.00-07.00 h) for eight consecutive days (days 0-7). A single 2.0-g dose of a 100 mg/mL LA-OMEP formulation was administered at 08.00 h on day 1. In Part B, 26 horses with squamous or glandular gastric disease were enrolled based on routine gastroscopic evaluation. Once enrolled, horses received 2.0 g of the 100 mg/mL LA-OMEP formulation by i.m. injection on days 0 and 7. Repeat gastroscopy was performed on days 14 (23 horses) or 16 (one horse).
  
  
  RESULTS
  In Part A, the percentage of time during which pH was above 4 exceeded 66% for days 1-4 in all horses and days 1-7 in four of the six horses studied. In Part B, healing was observed in all 22 (100%, 95% confidence interval [CI] 89-100%) horses with squamous disease and in nine of 12 (75%, 95% CI 47-92%) horses with glandular disease. Improvement, by at least one grade, was observed in all 22 (100%, 95% CI 89-100%) horses with squamous disease and in all 12 (100%, 95% CI 81-100%) horses with glandular disease. No worsening of lesions was observed. Lesion grade decreased over time in both the squamous (P<0.0001) and glandular (P = 0.0024) mucosa.
  
  
  CONCLUSIONS
  Small sample sizes.
  
  
  CONCLUSIONS
  The results of the present study compare favourably with previous reports on the pharmacodynamics of omeprazole and the clinical outcomes of trials reporting response to oral omeprazole therapy.
authors.affiliation: School of Veterinary Science, University of Queensland, Gatton, Queensland, Australia.|Luoda Pharma Pty Ltd, Caringbah, New South Wales, Australia.
authors.forename: B W
authors.identifier: http://orcid.org/0000-0002-0505-6228
authors.initials: BW
authors.lastname: Sykes
authors.affiliation: Centre for Pharmaceutical Innovation and Development, University of South Australia, Adelaide, South Australia, Australia.
authors.forename: K
authors.initials: K
authors.lastname: Kathawala
authors.affiliation: Centre for Pharmaceutical Innovation and Development, University of South Australia, Adelaide, South Australia, Australia.
authors.forename: Y
authors.initials: Y
authors.lastname: Song
authors.affiliation: Centre for Pharmaceutical Innovation and Development, University of South Australia, Adelaide, South Australia, Australia.
authors.forename: S
authors.initials: S
authors.lastname: Garg
authors.affiliation: Luoda Pharma Pty Ltd, Caringbah, New South Wales, Australia.
authors.forename: S W
authors.initials: SW
authors.lastname: Page
authors.affiliation: School of Veterinary Science, University of Queensland, Gatton, Queensland, Australia.
authors.forename: C
authors.initials: C
authors.lastname: Underwood
authors.affiliation: School of Veterinary Science, University of Queensland, Gatton, Queensland, Australia.
authors.forename: P C
authors.initials: PC
authors.lastname: Mills
mesh_terms: D000818:Animals; D000897:Anti-Ulcer Agents / Q000008:administration & dosage / Q000494:pharmacology*; D003692:Delayed-Action Preparations; D004304:Dosage Forms; D005260:Female; D005745:Gastric Acidity Determination; D006734:Horse Diseases / Q000188:drug therapy*; D006736:Horses; D007273:Injections, Intramuscular; D008297:Male; D009853:Omeprazole / Q000008:administration & dosage / Q000494:pharmacology*; D013276:Stomach Ulcer / Q000188:drug therapy / Q000662:veterinary*
chemical_list: D000897:Anti-Ulcer Agents; D003692:Delayed-Action Preparations; D004304:Dosage Forms; D009853:Omeprazole
keywords: gastric; glandular; horse; lesion; proton pump inhibitor; squamous