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Bilateral cannulation of guinea pigs for ototoxicity studies allows multiple assessments and reduction of animals
204
Abstracts
inhibited by nisoxetine (10 mg/kg). This study qualified the double cannulated ovariectomized rat model for evaluating the impact of central and peripheral acting compounds, and suggests that prolactin release may be inhibited both by central acting and peripherallyrestricted D2 agonists, DAT inhibitors, but not by NE uptake inhibitors. doi:10.1016/j.vascn.2012.08.158
Bilateral cannulation of guinea pigs for ototoxicity studies allows multiple assessments and reduction of animals Rachel L. Tapp, Matthew M. Abernathy, Jenifer A. Sweet, Joshua D. Yoder, Andrea A. Koch, David V. Gauvin, Theodore J. Baird MPI Research, Mattawan, MI, United States A normal compliment to the core safety assessment battery for new chemical entities that may have contact with or access to the inner ear requires an assessment of cochlear neurotoxicity. Placement of a middle ear catheter is required for ototoxicity assessment in guinea pigs for direct middle ear administration and repeat dose regimen. Historically, many laboratories utilized unilateral catheters based on the difficulty of the surgical catheterization. However, unilateral catheters allow for assessment of only one ear per animal. Studies where the drug is expected to reach the middle ear require a cytocochleogram and evaluation of relevant otic tissues. As the cytocochleogram requires complete dissection of the middle ear, the contralateral ear may be used for histological evaluation of the relevant otic tissues. Given this limitation, two separate middle ears are required to be treated and collected, which requires twice as many animals to obtain the data required for regulatory review. An evaluation of bilateral catheter placement was completed in male Albino Hartley (Elm Hill) guinea pigs (4 months of age). A cannula was inserted into each bulla of 5 animals and secured using methyl methacrylate and screws. Animals were utilized for a control treatment of 10% neomycin to demonstrate that both catheters were functional. Post-life tissue analysis demonstrated that bilateral catheterization of the middle ears in guinea pigs is a viable and reliable method that optimizes study designs by reducing the number of animals while still satisfying the required endpoints. doi:10.1016/j.vascn.2012.08.159
Gastric secretion in the rat: Influence of analgesics Astrid Jaehnige, Stefanie Hoell, Iris Erni, Silke Schlager-Schaelkle, Brian Guth, Sabine Pestel
Results: Metamizole (up to 300 mg/kg s.c.) reduced gastric volume, without providing adequate analgesia. In contrast, buprenorphine did not affect gastric secretion up to doses of 0.1 mg/kg s.c. or i.p., while analgesia started at 0.03 mg/kg s.c. or i.p. and was judged to be adequate at 0.1 mg/kg s.c. or i.p.. Plasma levels of buprenorphine after s.c. application were higher than after i.p. application despite similar analgesia. Slight effects of buprenorphine on carbachol-, cimetidine-, gastrozepine- or omeprazole-induced changes of gastric secretion were observed, but these did not lead to differences in interpretation of the data. Conclusion: We now assess drug-induced effects on gastric secretion under intraperitoneal buprenorphine analgesia. doi:10.1016/j.vascn.2012.08.160
An evaluation of the non-invasive faecal pellet assessment method as an early development screen for gastrointestinal liability Louise Marks, Des Cobey, Victoria Motyer, Lorna Ewart, Elizabeth Fantham, Nick Moore, Helen Prior, Jean-Pierre Valentin Safety Assessment UK, AstraZeneca R&D, Macclesfield, United Kingdom Gastrointestinal (GI) adverse effects contribute significantly to drug attrition and withdrawal and reduced patient compliance. Determination of GI liability early in a compound's development would be a valuable tool. We evaluated the non-invasive faecal pellet method in the rat and assessed the feasibility of combining this method with other studies. Han Wistar rats received a single dose of vehicle, atropine (0.5, 1, 5 or 25 mg/kg; po) or bethanechol (0.5 or 2 mg/kg; sc) and were pair-housed in metabolism cages. Pellets were removed at intervals out to 10 h post-dose (and at 24 h). Number, weight and appearance of pellets were noted. The method was added to a modified Irwin screen and a whole body plethysmography (WBP) study testing atropine (20 mg/kg; po) and bethanechol (2 mg/kg; sc), respectively. Pellets were collected from home cages out to 4 h in the Irwin or at the end of a 45 min WBP session. Atropine decreased (by 44, 89, 100, 100%) and bethanechol increased (by 11, 100%) pellet number. A decrease (atropine) and increase (bethanechol) in total pellet weight were also observed. Bethanechol produced softer pellets. Compound effects were maximal at the assumed Tmax and were detected in all study environments. Primary data generation was not affected by pellet collection. We have demonstrated that this method can detect the expected reference compound induced changes in pellet transit. The technique optimises data generation and would be a useful non-invasive ‘add-on’ to other study types (particularly WBP) and may flag GI effects earlier in preclinical development. doi:10.1016/j.vascn.2012.08.161
Boehringer-Ingelheim Pharma GmbH & Co. KG, Group General Pharmacology, Biberach an der Riss, Germany Introduction: Measuring drug-induced effects on gastric secretion involves assessment of gastric contents after pylorus ligation in the rat. This model as originally described (Shay) is performed without analgesia, despite signs of discomfort due to the procedure. This study investigated the influence of analgesia on gastric secretion as a refinement measure (one of the 3Rs). Methods: The analgesics metamizole (non-steroidal antiphlogistic) and buprenorphine (opioid) were used in a four hour pylorusligation model. Pain reduction (observational) and gastric secretion (volume, pH, total acidity) were assessed. Additionally, we tested whether buprenorphine use influences the effects of known, gastricsecretion modifying reference compounds. Plasma levels of the analgesics were determined in satellite animals.
Evaluation of gastric emptying in the cynomolgus monkey Abdel-Ilah El Amrani, René Michaud, Stéphane Loriot, Anne-Marie Bétat, Nicolas Aubert, Roy Forster, Jean-Jacques Legrand CiTox-LAB, Evreux, France Gastric emptying is one major parameter that may alter the rate of absorption of orally administered pharmaceuticals. Therefore, bioavailability studies during drug development require a suitable model of gastric emptying. In the present study, cynomolgus monkeys (2 males and 2 females) were given 60 mg of acetaminophen by oral route. Immediately thereafter, all animals received an intravenous injection of 2 mg/kg of the antiemetic and gastroprokinetic agent metoclopramide, or the same volume of the vehicle. Plasma
Abstracts
inhibited by nisoxetine (10 mg/kg). This study qualified the double cannulated ovariectomized rat model for evaluating the impact of central and peripheral acting compounds, and suggests that prolactin release may be inhibited both by central acting and peripherallyrestricted D2 agonists, DAT inhibitors, but not by NE uptake inhibitors. doi:10.1016/j.vascn.2012.08.158
Bilateral cannulation of guinea pigs for ototoxicity studies allows multiple assessments and reduction of animals Rachel L. Tapp, Matthew M. Abernathy, Jenifer A. Sweet, Joshua D. Yoder, Andrea A. Koch, David V. Gauvin, Theodore J. Baird MPI Research, Mattawan, MI, United States A normal compliment to the core safety assessment battery for new chemical entities that may have contact with or access to the inner ear requires an assessment of cochlear neurotoxicity. Placement of a middle ear catheter is required for ototoxicity assessment in guinea pigs for direct middle ear administration and repeat dose regimen. Historically, many laboratories utilized unilateral catheters based on the difficulty of the surgical catheterization. However, unilateral catheters allow for assessment of only one ear per animal. Studies where the drug is expected to reach the middle ear require a cytocochleogram and evaluation of relevant otic tissues. As the cytocochleogram requires complete dissection of the middle ear, the contralateral ear may be used for histological evaluation of the relevant otic tissues. Given this limitation, two separate middle ears are required to be treated and collected, which requires twice as many animals to obtain the data required for regulatory review. An evaluation of bilateral catheter placement was completed in male Albino Hartley (Elm Hill) guinea pigs (4 months of age). A cannula was inserted into each bulla of 5 animals and secured using methyl methacrylate and screws. Animals were utilized for a control treatment of 10% neomycin to demonstrate that both catheters were functional. Post-life tissue analysis demonstrated that bilateral catheterization of the middle ears in guinea pigs is a viable and reliable method that optimizes study designs by reducing the number of animals while still satisfying the required endpoints. doi:10.1016/j.vascn.2012.08.159
Gastric secretion in the rat: Influence of analgesics Astrid Jaehnige, Stefanie Hoell, Iris Erni, Silke Schlager-Schaelkle, Brian Guth, Sabine Pestel
Results: Metamizole (up to 300 mg/kg s.c.) reduced gastric volume, without providing adequate analgesia. In contrast, buprenorphine did not affect gastric secretion up to doses of 0.1 mg/kg s.c. or i.p., while analgesia started at 0.03 mg/kg s.c. or i.p. and was judged to be adequate at 0.1 mg/kg s.c. or i.p.. Plasma levels of buprenorphine after s.c. application were higher than after i.p. application despite similar analgesia. Slight effects of buprenorphine on carbachol-, cimetidine-, gastrozepine- or omeprazole-induced changes of gastric secretion were observed, but these did not lead to differences in interpretation of the data. Conclusion: We now assess drug-induced effects on gastric secretion under intraperitoneal buprenorphine analgesia. doi:10.1016/j.vascn.2012.08.160
An evaluation of the non-invasive faecal pellet assessment method as an early development screen for gastrointestinal liability Louise Marks, Des Cobey, Victoria Motyer, Lorna Ewart, Elizabeth Fantham, Nick Moore, Helen Prior, Jean-Pierre Valentin Safety Assessment UK, AstraZeneca R&D, Macclesfield, United Kingdom Gastrointestinal (GI) adverse effects contribute significantly to drug attrition and withdrawal and reduced patient compliance. Determination of GI liability early in a compound's development would be a valuable tool. We evaluated the non-invasive faecal pellet method in the rat and assessed the feasibility of combining this method with other studies. Han Wistar rats received a single dose of vehicle, atropine (0.5, 1, 5 or 25 mg/kg; po) or bethanechol (0.5 or 2 mg/kg; sc) and were pair-housed in metabolism cages. Pellets were removed at intervals out to 10 h post-dose (and at 24 h). Number, weight and appearance of pellets were noted. The method was added to a modified Irwin screen and a whole body plethysmography (WBP) study testing atropine (20 mg/kg; po) and bethanechol (2 mg/kg; sc), respectively. Pellets were collected from home cages out to 4 h in the Irwin or at the end of a 45 min WBP session. Atropine decreased (by 44, 89, 100, 100%) and bethanechol increased (by 11, 100%) pellet number. A decrease (atropine) and increase (bethanechol) in total pellet weight were also observed. Bethanechol produced softer pellets. Compound effects were maximal at the assumed Tmax and were detected in all study environments. Primary data generation was not affected by pellet collection. We have demonstrated that this method can detect the expected reference compound induced changes in pellet transit. The technique optimises data generation and would be a useful non-invasive ‘add-on’ to other study types (particularly WBP) and may flag GI effects earlier in preclinical development. doi:10.1016/j.vascn.2012.08.161
Boehringer-Ingelheim Pharma GmbH & Co. KG, Group General Pharmacology, Biberach an der Riss, Germany Introduction: Measuring drug-induced effects on gastric secretion involves assessment of gastric contents after pylorus ligation in the rat. This model as originally described (Shay) is performed without analgesia, despite signs of discomfort due to the procedure. This study investigated the influence of analgesia on gastric secretion as a refinement measure (one of the 3Rs). Methods: The analgesics metamizole (non-steroidal antiphlogistic) and buprenorphine (opioid) were used in a four hour pylorusligation model. Pain reduction (observational) and gastric secretion (volume, pH, total acidity) were assessed. Additionally, we tested whether buprenorphine use influences the effects of known, gastricsecretion modifying reference compounds. Plasma levels of the analgesics were determined in satellite animals.
Evaluation of gastric emptying in the cynomolgus monkey Abdel-Ilah El Amrani, René Michaud, Stéphane Loriot, Anne-Marie Bétat, Nicolas Aubert, Roy Forster, Jean-Jacques Legrand CiTox-LAB, Evreux, France Gastric emptying is one major parameter that may alter the rate of absorption of orally administered pharmaceuticals. Therefore, bioavailability studies during drug development require a suitable model of gastric emptying. In the present study, cynomolgus monkeys (2 males and 2 females) were given 60 mg of acetaminophen by oral route. Immediately thereafter, all animals received an intravenous injection of 2 mg/kg of the antiemetic and gastroprokinetic agent metoclopramide, or the same volume of the vehicle. Plasma