Sydney School of Veterinary Science istock photo Research update - medicines for koalas Merran Govendir Associate Professor in Veterinary Pharmacology merran.govendir@sydney.edu.au 1
Introduction Who we are, what we do Analgesics Antimicrobials Future research plans introduction 3-4
Who we are! Who we are! introduction 3-4
publications 1. Griffith JE et al. Absorption of enrofloxacin & marbofloxacin after oral and subcutaneous administration in diseased koalas. J Vet Pharm Ther 2010;33:595-604. 2. Govendir M et al. Plasma concentrations of chloramphenicol after subcutaneous administration to koalas with chlamydiosis. J Vet Pharm Ther 2012;35:147-154. 3. Black LA et al. Pharmacokinetics of chloramphenicol following administration of intravenous & subcutaneous chloramphenicol succinate & chloramphenicol subcutaneous base to koalas. J Vet Pharm Ther 2013: 36; 478-485. 4. Kimble B et al. Quantitation of meloxicam in the plasma of koalas by improved high performance liquid chromatography 2013 J Vet Sci 14 (1) 7-14. 5. Kimble B et al. Pharmacokinetics of meloxicam in koalas after intravenous, subcutaneous & oral administration. J Vet Pharm Ther 2012: 36; 486-493 6. Black LA, et al. Pharmacokinetics of fluconazole following oral and intravenous administration to koalas. J Vet Pharm & Ther (2014) 37; 90-98 7. Black LA et al. Evaluation of enrofloxacin use in koalas using population pharmacokinetics and Monte Carlo simulation. J Vet Pharm & Ther (2014) 37; 301-311 8. Kimble B et al. A comparative study of in vitro metabolism of meloxicam in koalas, brush tail possums, ring tail possums rats and dogs. J Comp Biochem Physio C (2014) 161; 7-14 9. De Kauwe T, et al Analgesic drug regimens used for koalas in Australia and their perceived efficacy. J Zoo and Wildlife Medicine (2014) 45; 350-356 10. Black LA et al In-vitro activities of chloramphenicol, florfenicol and enrofloxacin against Chlamydia pecorum isolated from koalas. Aust Vet J (2015) 93;420-423 11. Govendir M et al., Pharmacokinetic indices of oral fluconazole administration to koalas infected with cryptococcosis. J Vet Pharm & Ther (2016); 39; 412 415 12. Budd C et al., Florfenicol as a possible treatment for chlamydiosis in koalas. Accepted Aust Vet J 13. Gharibi S et al., Pharmacokinetics of posaconazole in koalas after intravenous and oral administration. J Vet Pharm and Ther (2017) DOI:10.1111/jvp.12407 Summary 18
Analgesics Meloxicam (Metacam ) A non-steroidal anti-inflammatory (NSAID) Enrofloxacin 4
In-vivo meloxicam - NSAID Meloxicam plasma half life Hours People 15-20 Dog 24 Koala 1.19 (range 0.71 1.62 ) Meloxicam 0.1mg/kg oral (n= 3) & 0.1mg/kg sub cut (n = 3 both groups) Negligible oral absorption! Meloxicam 7
In-vitro microsome assays 1994 istock photo Microsome assay Microsome s 10
Generalist folivore Specialist folivores Common brushtail possum Common ringtail possum Rate of disappearance of meloxicam when incubated with liver microsomes
Koalas diet - high concentrations of dietary plant secondary metabolites (PSM) such as -terpenes -phenolics -formyphloroglucinols Phenolics 20% mostly undergo Phase 2 conjugation Terpenoids undergo Phase 1 oxidation Lignin 15% Lipids (including essential oils) 16% Non-cellulose carbohydrate 17% Ash 5% Cellulose (requires bacterial fermentation) 19% Protein 8% Benjamin 9
In people & other species metabolism of NSAIDs requires the enzyme: Cytochrome (CYP) 2C or CYP2C Phenolics 20% mostly undergo Phase 2 conjugation Terpenoids undergo Phase 1 oxidation Lignin 15% Lipids (including essential oils) 16% Non-cellulose carbohydrate 17% Ash 5% Cellulose (requires bacterial fermentation) 19% Protein 8% Benjamin 9
Results 350 300 250 200 150 100 50 0 7.8 7.8 11.8 3 144.7 203.6 In-vitro Cl int (µl/min/mg protein) n.d. 128 289.2 92.2 48 30.6 26.8 4.8 n.d. 6.8 18.8 10.4 Rat Koala Ringtail possum Brushtail possum Tolbutamide Fluvastatin Indomethacin Meloxicam Diclofenac Flurbiprofen In-vitro Cl int of CYP2C9 substrates determined from hepatic microsomes of rat (pooled) and E. feeders (n = 1, each species); numbers indicate in-vitro Cl int (µl/min/mg protein) estimated from single time point; n.d. (not determined): as the depletion of substrates was extremely fast, and the in-vitro Cl int (at least > 350 µl/min/mg protein) was not determined. n.d.
Provided by Dr Rebecca Johnson & Koala Genome Group
Tramdol Tramadol What is it? Analgesic Opioid like enhances serotonin action in CNS Why? Port Koala Hospital request introduction 3-4
Tramadol metabolism: rat (black graph) vs koala (pink graph) uv 50000 40000 Baseline t = 0 min 30000 20000 10000 0-10000 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 8.5 9.0 9.5 10.0 10.5 11.0 11.5 12.0 12.5 13.0 13.5 14.0 14.5 15.0 15.5 min uv 45000 40000 35000 30000 25000 t = 30 min 20000 15000 10000 5000 0-5000 -10000 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 8.5 9.0 9.5 10.0 10.5 11.0 11.5 12.0 12.5 13.0 13.5 14.0 14.5 15.0 15.5 min uv 40000 35000 30000 25000 t = 60 min 20000 15000 10000 5000 0-5000 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 8.5 9.0 9.5 10.0 10.5 11.0 11.5 12.0 12.5 13.0 13.5 14.0 14.5 15.0 15.5 min
Cefovecin Convenia - antibacterial Amoxicillin - antibacterial Florfenicol - to date disappointing treatment for chlamydiosis Posaconazole Noxafil antifungal Summary 18
Cefovecin One subcut injection has a duration of action of 10 to 14 days in dogs & cats Due to > 98% plasma protein binding in these species introduction 3-4
protein binding (%) In-vitro cefovecin study In-vivo cefovecin study undertaken at Taronga zoo 100 90 80 70 60 50 40 30 20 10 0 Horse koala 10 25 50 100 200 300 Cefovecin concentration (ug/ml) Cefovecin blood concentration < 1 µg/ml at all time points over 4 days - Does not have a long duration in the koala Absorption 16
Amoxicillin Why not amoxicillin clavulanate? 10 mg/kg subcutaneous injection introduction 3-4
Time AMX concentration (µg/ml) Darwin Freya Mallee* Max* Rubi* Storm* 0 h - - - - - - 0.5 h 0.38 0.41 - - - - 1 h 0.65 0.41 - - - - 2 h 0.57 0.38 - - - - 4 h 0.43 0.31 - - - - 6 h 0.30 0.31 - - - - 8 h 0.27 0.31 - - - - 12 h 0.24 0.32 - - - - 24 h 0.23 0.17 - - - - * All values for koalas Mallee, Max, Rubi and Storm were not detectable. Enrofloxacin 4
Posaconazole Antifungal drug 6 mg/kg oral administration Likely effective to treat cryptococcosis introduction 3-4
Future plans Future plans *tramadol in-vivo study *fentanyl patches (analgesic) study *continue NSAID study *efficacious treatment for chlamydiosis introduction 3-4
Updates on research Facebook: https://www.facebook.com/koalamedicineresearch Twitter: https://twitter.com/koalamedicine Blog: https://animalmedicineresearch.wordpress.com Summary 17
How can you you assist? Need students Donations to support this research introduction 3-4
Thanks to to Cheyne Flanagan & The Port Macquarie Koala Hospital Larry Vogelnest & Taronga Zoo Fumie Tokonami & Currumbin Sanctuary Wildlife hospital Amber Gillett and Australia Zoo Wildlife Hospital Jon Hanger & Jo Loader Endeavour Veterinary Ecology Financial support from Hermon Slade Foundation Boehringer Ingelheim Fin Violet Winifred Scott Foundation Port Macquarie Koala Hospital Sydney School of Veterinary Science Services 7-8