Bioavailability and Tolerability of Topical and Oral Diclofenac Sodium Administration in Healthy Ponies

• Published in: Journal of equine veterinary science Vol. 33; no. 1; pp. 22 - 26
• Main Authors: Azevedo, Marcos S., De La Côrte, Flavio D., Brass, Karin E., Dalmora, Sergio L., Machado, Francine T., Pompermayer, Endrigo, Dau, Stefano L., Santa'Ana, Laureana A.
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01-01-2013
• Subjects: alkaline phosphatase; bioavailability; coagulation; Concentration; eosinophils; fibrinogen; hematocrit; hemoglobin; High-performance liquid chromatography; Horses; leukocyte count; lymphocytes; Nonsteroidal anti-inflammatory drugs; oral administration; Pharmacokinetics; phenylbutazone; prothrombin; synovial fluid; thromboplastin; topical application; Horses; Nonsteroidal anti-inflammatory drugs; Concentration; Pharmacokinetics; High-performance liquid chromatography
• ISSN: 0737-0806; 1542-7412
• DOI: 10.1016/j.jevs.2012.04.013

Aiming to characterize the bioavailability and assess the safety of topical and oral treatment of diclofenac sodium in healthy ponies, 18 animals were divided in three groups: one treated with topical (group I, n = 6), the second with oral diclofenac (group II, n = 6) at 2.5 mg/kg for 3 days, and the third group received 2.2 mg/kg oral phenylbutazone (group III, n = 6) also for 3 days to serve as positive control. To evaluate bioavailability, blood samples were collected before and at 0, 0.5, 1, 3, 6, 9, 12, 24, 36, 48, 60, 72, 96, 120, and 144 hours after starting treatment. To evaluate diclofenac sodium concentration in the synovial fluid, samples of six ponies (group I, n = 3; group II, n = 3) were collected at 6, 12, and 24 hours after starting the treatment.
Samples collected before and at 0, 24, 48, 72, 96, 120, and 144 hours after starting treatment were also used for complete blood cell count, biochemistry, and coagulation profile. A difference was found between groups I and II regarding prothrombin time, activated partial thromboplastin time, fibrinogen, packed cell volume, hemoglobin, red and white blood cell count, polymorphonuclear cells, band cells, lymphocytes, eosinophils, and alkaline phosphatase. Similar results were found between groups II and III; however, activated partial thromboplastin time did not differ. Plasma concentration of diclofenac sodium in group II was higher than that in group I. Synovial diclofenac concentration was higher than minimal therapeutic levels in groups I and II.