Validation of an HPLC assay for determination of Telazol in pregnant pigs: application to placental transfer study

Abstract

Anesthetics utilized for the immobilization of pregnant mammals are prone to crossing the placental barrier and cause adverse effects to the fetuses. In this study, we develop a facile method employing high performance liquid chromatography (HPLC) for the study of Telazol crossing the placental barrier of pregnant pigs. The method mainly relies on the efficient extraction strategy that includes the mobile phase composed of 10 mM ammonium acetate aqueous solution-acetonitrile (1:4, v/v). When the injected dose of Telazol is 10 mg/kg (5 mg/kg of each constituent drug, zolazepem and tiletamine), zolazepam can cross the placental barrier as it is detected in both uterus and umbilical cord with approximately the same content. Conversely, tiletamine is detected in neither uterus nor umbilical cord, indicating the absence of placental transfer of tiletamine. The different absorption rates of the two dosage-equal compounds by pigs are found to be the main cause of their different abilities to cross the placental barrier.

Physiological and Clinical Responses in Pigs in Relation to Plasma Concentrations during Anesthesia with Dexmedetomidine, Tiletamine, Zolazepam, and Butorphanol

“…However, the findings of the current study did not appear to have this difference in t ½ (zolazepam 1.2 h versus tiletamine 1.5 h) after administration IM. Our findings may be a result of the combination of drugs that were similar to those found in a study of pregnant pigs [ 41 ], where the C max for both tiletamine and zolazepam was 50–60 min (compared to 10–12 min in the present study), and where the elimination of zolazepam was slow and tiletamine rapid. The study also showed that zolazepam, but not tiletamine, was detected in the uterus and umbilical cord and thereby probably having an effect on the fetus; this finding must be taken into consideration when used in pregnant sows.…”