الكاتب: Multiple References

The distribution of trimethoprim (TMP) and sulfadiazine (SDZ) into subcutaneously implanted noninfected tissue chambers was studied in healthy adult ponies. Six ponies were given an oral TMP ⁄ SDZ paste formulation at a dose of 5 mg ⁄ kg TMP and 25 mg ⁄ kg SDZ at 12 h intervals for 2 days in order to reach steady-state concentrations. Plasma concentrations and tissue chamber fluid (TCF) concentrations of both drugs were measured at regular intervals during a period commencing 24 h after the last oral administration. The peak concentration of TMP (mean ± SD) was 2.92 ± 0.86 lg ⁄ mL for plasma and 1.09 ± 0.25 lg ⁄ mL for TCF. For SDZ, the mean peak concentration was 40.20 ± 14.74 lg ⁄ mL for plasma and 23.48 ± 5.84 lg ⁄ mL for TCF. TMP peak concentrations in plasma were reached at 3.17 ± 03.48 h and those in TCF at 7.33 ± 03.72 h. SDZ peak concentrations in plasma were reached at 1.83 ± 02.04 h and those in TCF at 8.00 ± 03.10 h. Concentrations of TMP and SDZ in TCF remained above the generally accepted breakpoint for susceptibility (0.5 ⁄ 9.5 for the TMP ⁄ SDZ combination) for 12 h. Therefore, in ponies oral administration of TMP ⁄ SDZ at a dose rate of 30 mg ⁄ kg given twice daily in the form of a paste should be appropriate for effective treatment of infections caused by susceptible bacteria.