Biodisponibilidade e tolerabilidade do diclofenaco de sódio via tópica ou oral em pôneis sadios

Abstract

Studies on the topical use of diclofenac in horses deal mostly with pharmacokinetics and the clinical effect of the medication, few studies addressed its tolerability or its oral use. The aim of this study was to obtain data related to pharmacokinetics and distribution of diclofenac sodium in synovial fluid after oral or topical administration in healthy ponies as well as to evaluate the tolerability of oral and topical diclofenac sodium administered on a frequency similar to a treatment period. Healthy ponies were divided into three groups and treated with topical (group I, n = 6) or oral (group II, n = 6) diclofenac at a dose of 2.5 mg kg-1 and oral phenylbutazone (group III, n = 3) at a dose of 2.2 mg kg-1. To evaluate the bioavailability blood samples were collected at different times, from 30 minutes to 144 hours and synovial fluid samples 6, 12 and 24 hours, after starting treatment. Blood samples collected 24 hours before and until 144 hours after starting treatment were used for CBC, WBC, biochemical and coagulation profiles. A significant difference was found between group I and group II on prothrombin time, activated partial thromboplastin time, fibrinogen, hematocrit, hemoglobin, erythrocytes, total leukocytes, neutrophils, band cells, lymphocytes, eosinophils, and alkaline phosphatase. Similar results were found between group II and group III, however, the activated partial thromboplastin time did not differ. Even though the plasma concentration of diclofenac sodium was higher in group II than in group I, the synovial concentration tended to be higher in group I. The diclofenac bioavailability and tolerability data obtained in ponies showed that the topic administration delivered therapeutic concentrations of diclofenac and proved to be safer, as the oral administration resulted in blood changes.