Pharmacokinetics and tissue residue depletion of fenbendazole in healthy and bronchopneumonic calves : a thesis /
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| Format: | Thesis Book |
| Language: | English |
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[College Station, Tex.] :
[Texas A&M University],
[1991]
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| Subjects: |
| Abstract: | ABSTRACT: The objective of this study was to determine the differences in pharmacokinetic parameters and tissue residue profiles between healthy and bronchopneumonic calves for a highly-metabolized, lipid-soluble drug (fenbendazole). Twenty-four cross-breed calves were commercially obtained and determined to be free of clinical disease. Bronchopneumonia was experimentally induced in twelve of the calves. A bronchopneumonic calf was then paired with a healthy calf and both were given an oral dose of 10 mg/kg of a commercial suspension of fenbendazole. Blood samples were taken at regualar intervals for up to seventeen days. Tissue samples were collected from each calf at the time of necropsy. Both plasma and tissue samples were analyzed by HPLC to determine the concentrations of fenbendazole (FBZ), the sulfone (FBZ-SO₂) and sulfoxide (FBZ-SO) derivatives that were present. Significant differences (P<0.05) were observed between the healthy and pneumonic groups for the pharmacokinetic parameters of plasma AUC (area under the concentration vs. time curve) AUMC (area under the first moment curve), and MRT (mean residence time). The MRT of FBZ increased from 34.0 ± 11.6 hours (healthy calves) to 65.9 ± 21.0 hours (pneumonic calves), the FBZ-SO MRT increased from 39.6 ± 10.3 hours (healthy calves) to 78.4 ± 25.7 hours (pneumonic calves), and the MRT of the FBZ-SO₂ increased from 55.4 ± 10.6 hours (healthy calves) to 104 ± 32.7 hours (pneumonic calves). The average concentration of FBZ in liver tissue was below the tolerance level in the healthy calves (732 ng/g) on the day 10, but not in the pneumonic calves (2030 ng/g). The results of this study suggest that tissue concentrations of FBZ in pneumonic calves may be higher than the prescribed tolerance level for a longer time than in healthy calves. |
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| Item Description: | Typescript (photocopy). Vita. "Submitted to the Office of Graduate Studies Texas A&M University in partial fulfillment of the requirements for the degree of Master of Science December 1991." "Major subject: Veterinary Physiology." Approved as to style and content by: S. A. Brown, D. M. Boothe, T. M. Craig, J. G. Anderson, J. F. Hunter. |
| Physical Description: | x, 62 leaves : illustrations ; 29 cm |
| Bibliography: | Includes bibliographical references. |