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Liao P, Ravis W, Clark-Price S, Gerken K, Duran S, Elrod S. Volume kinetic analysis of two crystalloid fluid bolus rates in anesthetized cats. Vet Anaesth Analg 2023. [DOI: 10.1016/j.vaa.2022.09.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Mora-Pereira M, Abarca EM, Duran S, Ravis W, McMullen RJ, Fischer BM, Lee YHP, Wooldridge AA. Sustained-release voriconazole-thermogel for subconjunctival injection in horses: ocular toxicity and in-vivo studies. BMC Vet Res 2020; 16:115. [PMID: 32295599 PMCID: PMC7160932 DOI: 10.1186/s12917-020-02331-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 04/05/2020] [Indexed: 12/13/2022] Open
Abstract
Background Keratomycosis is a relatively common, sight threatening condition in horses, where treatment is often prolonged and costly. Subconjunctival (SCo) injections offer less resistance to drug diffusion than the topical route, resulting in better penetration to the ocular anterior segment. Voriconazole, a second generation triazole antifungal, is effective against common fungal organisms causing keratomycosis. If combined with a thermogel biomaterial, voriconazole can be easily injected in the SCo space to provide sustained drug release. The purpose of this study was to evaluate the drug concentrations in the anterior segment and clinical effects after SCo injections of voriconazole-containing thermogel: poly (DL-lactide-co-glycolide-b-ethylene glycol-b-DL-lactide-co-glycolide) (PLGA-PEG-PLGA) in healthy equine eyes. Results Voriconazole aqueous humor (AH) and tear concentrations were compared between 6 horses, receiving 1% voriconazole applied topically (0.2 mL, q4h) (Vori-Top) or 1.7% voriconazole-thermogel (0.3 mL) injected SCo (Vori-Gel). For the Vori-Gel group, voriconazole concentrations were measured in AH and tears at day 2 and then weekly for 23 days, and at day 2 only for the Vori-Top group. Ocular inflammation was assessed weekly (Vori-Gel) using the modified Hackett-McDonald scoring system. Ocular tissue concentrations of voriconazole following SCo 1.7% voriconazole-thermogel (0.3 mL) injections were evaluated post euthanasia in 6 additional horses at 3 different time points. Three horses received bilateral injections at 2 h (n = 3, right eye (OD)) and 48 h (n = 3, left eye (OS)) prior to euthanasia, and 3 horses were injected unilaterally (OS), 7 days prior to euthanasia. Voriconazole-thermogel was easily injected and well tolerated in all cases, with no major adverse effects. On day 2, drug concentrations in tears were higher in the Vori-Top, but not statistically different from Vori-Gel groups. For the Vori-Gel group, voriconazole was non-quantifiable in the AH at any time point. Total voriconazole concentrations in the cornea were above 0.5 μg/g (the target minimum inhibitory concentration (MIC) for Aspergillus sp.) for up to 48 h; however, concentrations were below this MIC at 7 days post treatment. Conclusions Voriconazole-thermogel was easily and safely administered to horses, and provided 48 h of sustained release of voriconazole into the cornea. This drug delivery system warrants further clinical evaluation.
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Affiliation(s)
- Mariano Mora-Pereira
- J. T. Vaughan Large Animal Teaching Hospital, Auburn University, Auburn, AL, USA
| | - Eva M Abarca
- J. T. Vaughan Large Animal Teaching Hospital, Auburn University, Auburn, AL, USA.
| | - Sue Duran
- J. T. Vaughan Large Animal Teaching Hospital, Auburn University, Auburn, AL, USA
| | - William Ravis
- Department of Drug Discovery and Development, Auburn University, Auburn, AL, USA
| | - Richard J McMullen
- J. T. Vaughan Large Animal Teaching Hospital, Auburn University, Auburn, AL, USA
| | - Britta M Fischer
- J. T. Vaughan Large Animal Teaching Hospital, Auburn University, Auburn, AL, USA
| | | | - Anne A Wooldridge
- J. T. Vaughan Large Animal Teaching Hospital, Auburn University, Auburn, AL, USA
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Agne GF, Jung SW, Wooldridge AA, Duran SH, Ravis W, Toribio R. Pharmacokinetic and pharmacodynamic properties of orally administered torsemide in healthy horses. J Vet Intern Med 2018; 32:1428-1435. [PMID: 29770976 PMCID: PMC6060311 DOI: 10.1111/jvim.15213] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 02/05/2018] [Accepted: 04/19/2018] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND Diuretic treatment is the mainstay for management of congestive heart failure in horses, and its use has been restricted to injectable medications because no currently data supports the use of PO administered loop diuretics. OBJECTIVES To determine the pharmacokinetic and pharmacodynamic properties of PO administered torsemide and, determine if PO administered torsemide, could be used as an alternative to injectable diuretics in the horse. ANIMALS Six healthy adult mares. METHODS A 2-phase, prospective study, that consisted of pharmacokinetic profiling of a single dose (6 mg/kg PO) and pharmacodynamic effects of long-term torsemide administration (2 mg/kg PO q12h) for 6 days in healthy horses. RESULTS Pharmacokinetic analysis identified a peak concentration (Cmax ) of 10.14 µg/mL (range, 6.79-14.69 µg/mL) and elimination half-life (T1/2 ) 9.2 hours (range, 8.4-10.4 hours). The area under the plasma drug concentration over time curve (AUC) was 80.7 µg × h/mL (range, 56.5-117.2 µg × h/mL). A statistically significant increase in urine volume and decrease in urine specific gravity were found from day 0 (baseline) to day 6 (P < .0001). Significant alterations in biochemical variables included hyponatremia, hypokalemia, hypochloremia, and increased serum creatinine concentration. Mean arterial blood pressure significantly decreased on day 6 (57.7 ± 8.8 mm Hg, P = .001) as compared with baseline (78 ± 6.1 mm Hg). Serum aldosterone concentrations significantly increased after 6 days of torsemide administration (P = .0006). CONCLUSIONS AND CLINICAL IMPORTANCE PO administered torsemide (4 mg/kg/day) successfully reached therapeutic concentrations in blood, induced clinically relevant diuresis, and resulted in moderate pre-renal azotemia and electrolyte disturbances.
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Affiliation(s)
- Gustavo F Agne
- Department of Clinical Sciences, College of Veterinary Medicine, Auburn University, Auburn, Alabama
| | - Seung Woo Jung
- Department of Clinical Sciences, College of Veterinary Medicine, Auburn University, Auburn, Alabama
| | - Anne A Wooldridge
- Department of Clinical Sciences, College of Veterinary Medicine, Auburn University, Auburn, Alabama
| | - Susan H Duran
- Department of Clinical Sciences, College of Veterinary Medicine, Auburn University, Auburn, Alabama
| | - William Ravis
- Department of Drug Discovery and Development, Harrison School of Pharmacy, Auburn University, Auburn, Alabama
| | - Ramiro Toribio
- Department of Clinical Sciences, College of Veterinary Medicine, The Ohio State University, Columbus, Ohio
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Cuming RS, Abarca EM, Duran S, Wooldridge AA, Stewart AJ, Ravis W, Babu RJ, Lin YJ, Hathcock T. Development of a Sustained-Release Voriconazole-Containing Thermogel for Subconjunctival Injection in Horses. ACTA ACUST UNITED AC 2017; 58:2746-2754. [DOI: 10.1167/iovs.16-20899] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- Rosemary S. Cuming
- J. T. Vaughan Large Animal Teaching Hospital, Auburn University, Auburn, Alabama, United States
| | - Eva M. Abarca
- J. T. Vaughan Large Animal Teaching Hospital, Auburn University, Auburn, Alabama, United States 2Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Sue Duran
- J. T. Vaughan Large Animal Teaching Hospital, Auburn University, Auburn, Alabama, United States
| | - Anne A. Wooldridge
- J. T. Vaughan Large Animal Teaching Hospital, Auburn University, Auburn, Alabama, United States
| | - Allison J. Stewart
- University of Queensland, School of Veterinary Science, Gatton, Queensland, Australia
| | - William Ravis
- Department of Drug Discovery and Development, Auburn University, Auburn, Alabama, United States
| | - R. Jayachandra Babu
- Department of Drug Discovery and Development, Auburn University, Auburn, Alabama, United States
| | - Yuh-Jing Lin
- Department of Drug Discovery and Development, Auburn University, Auburn, Alabama, United States
| | - Terri Hathcock
- Department of Pathobiology, Auburn University, Auburn, Alabama, United States
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Serena A, Schumacher J, Schramme MC, Degraves F, Bell E, Ravis W. Concentration of methylprednisolone in the centrodistal joint after administration of methylprednisolone acetate in the tarsometatarsal joint. Equine Vet J 2010; 37:172-4. [PMID: 15779632 DOI: 10.2746/0425164054223778] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
REASONS FOR PERFORMING STUDY The centrodistal (CD) and tarsometatarsal (TMT) joints are often injected individually with a corticosteroid to resolve lameness caused by osteoarthritis (OA). There are no data available regarding diffusion of methylprednisolone (MP) from the TMT joint to the CD joint. HYPOTHESIS A therapeutic concentration of MP diffuses into the CD joint after methylprednisolone acetate (MPA) is administered into the TMT joint. OBJECTIVE To measure the concentration of MP in the CD joint after MPA was administered into the TMT joint. METHODS MPA was administered into a TMT joint of 16 horses. At different times, the ipsilateral CD joint of these horses was injected with a small amount of saline and recovered saline was measured for concentration of MP using high performance liquid chromatography. RESULTS Six hours after administration of MPA into the TMT joint, a therapeutic concentration of MP was found in all 10 CD joints sampled at this time. CONCLUSIONS Horses with pain arising from the distal 2 joints of the hock can be treated by administering MPA into the TMT joint alone. POTENTIAL RELEVANCE Administering MPA into the TMT joint only, to treat OA of the distal 2 hock joints, reduces the difficulties and risks associated with centesis of the CD joint.
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Affiliation(s)
- A Serena
- Department of Clinical Sciences, College of Veterinary Medicine, Auburn University, Auburn, Alabama, USA
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Abstract
The pharmacokinetics of levamisole was studied in 20 broiler breeder chickens (chickens that give eggs to breed broilers). A single dose of levamisole (40 mg/kg) was administered orally or intravenously to chickens before the onset of egg production, prelay (age = 22 weeks), and repeated at the peak of egg production (age = 32 weeks). A high-pressure liquid chromatographic with ultraviolet detection method (HPLC-UV) was used for quantification of levamisole in plasma. Using compartmental analysis, levamisole followed a three-compartmental open model with mean values of alpha = 0.1224 and 0.4968, beta = 0.01663 and 0.01813, gamma = 0.002 and 0.002/min at the prelay and at the peak of egg production periods, respectively. The mean values for volume of distribution at steady state (V(ss)), determined by compartmental analysis, were significantly different for prelay and peak of egg production (8.358 and 13.581 mL/kg), respectively.
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Affiliation(s)
- H El-Kholy
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, USA
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Ravis W. Pharmacokinetics of eplerenone after single and multiple dosing in subjects with and without renal impairment. Clin Pharmacol Ther 2004. [DOI: 10.1016/j.clpt.2003.11.142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Diskin CJ, Gupta RB, Ravis W, Stokes TJ, Dansby LM, Carter TB, Thomas SG. Edema, oncotic pressure, and free entropy: novel considerations for the treatment of edema through attention to thermodynamics. Nephron Clin Pract 2000; 78:131-8. [PMID: 9496727 DOI: 10.1159/000044900] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Over 170 years after Richard Bright and a century after Ernest H. Starling, the development, location, and severity of edema in patients with renal impairment continue to baffle the predictions of most nephrologists. While much of the phenomenon can be explained by levels of serum proteins, or hydrostatic pressures, there are stunning exceptions well known to any practicing nephrologist. Some of the derangement is undoubtedly due to unmeasured but well-known variables, such as membrane permeability; however, other factors such as free entropy of plasma are also clearly involved. The study of other polyelectrolyte colloids, similar to plasma proteins, for industrial purposes has led to the identification of various phenomena such as counterion condensation that can result in loss of entropy and consequently osmotic pressure. Variables known to result in a loss of free entropy, such as pH, oxidation products and ligand binding, are discussed. Older equations developed by van't Hoff and Donnan might require replacement by newer mathematical models such as the nonlinear Poisson-Boltzmann equation or the Monte Carlo simulator. Attempts to restore free entropy to plasma would be a more physiological treatment of edema than diuretic use. Implications are noted for future drug development to treat edema.
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Affiliation(s)
- C J Diskin
- Hypertension, Nephrology, Dialysis and Transplantation Clinic, Opelika, Ala 36802, USA
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Diskin CJ, Stokes TJ, Thomas SG, Ravis W, Lock S, Thomas J, Panus LW, Dansby L, Carter T. An analysis of the effect of routine medications on hemodialysis vascular access survival. Nephron Clin Pract 2000; 78:365-8. [PMID: 9546712 DOI: 10.1159/000044961] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Abstract
Histamine type II (H2) antagonists inhibit gastric acid secretion and are useful in treating gastric and duodenal ulcer disease. To provide some information on the pharmacokinetics of the H2 antagonist cimetidine, adult horses were given 3.3 mg/kg cimetidine intravenously (iv) or 3.3 and 10 mg/kg orally. Plasma cimetidine concentrations after 3.3 mg/kg orally were too low to measure. Following 3.3 mg/kg iv, cimetidine displayed two-compartment characteristics with a t1/2 of 0.083 +/- 0.039 h and t1/2 of 2.23 +/- 0.64 h. The total body clearance was 0.443 +/- 0.160 litre/h/kg and the mean residence time was 2.74 +/- 1.11 h. This clearance and t1/2 are similar to that in man. The volume of distribution (Vss) and volume of the central compartment (Vc) were 1.138 +/- 0.230 and 0.276 +/- 0.102 litre/kg, respectively. After a single oral dose of 10 mg/kg as crushed tablets, peak plasma concentration of 1.81 +/- 0.82 micrograms/ml occurred at approximately 1.4 h. Oral absorption of cimetidine appeared variable and slow with an extent of absorption of 0.296 +/- 0.183 and a mean residence time for absorption of 1.99 +/- 0.79 h. This was less than in man. Based on a desired average steady state plasma concentration of 1.0 microgram/ml, 11.0 mg/kg/day iv and 48 mg/kg/day orally can be recommended in adult horses.
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Affiliation(s)
- G B Smyth
- Department of Large Animal Surgery and Medicine, College of Veterinary Medicine, Auburn University, Alabama 36849-5522
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