Titration of subcutaneously administered eprinomectin against mature and immature nematodes in cattle.

Eprinomectin has been approved for use as a topically applied endectocide for beef and dairy cattle. To determine if eprinomectin has utility as an injectable anthelmintic, it was titrated at 0.05, 0.

Synthesis of 1,19-Aza-1,19-desoxy-avermectin B(1a): The First Avermectin Macrolactam.

The first synthesis of 1,19-aza-1,19-desoxy-avermectin B(1a) (2) is described. This new macrolactam, prepared efficiently from avermectin B(1a) (1a) in seven steps, was designed to form an intramolecular hydrogen bond between the amide carbonyl and the adjacent C7 tertiary hydroxyl via a six-center hydrogen bonding network. The presence of this intramolecular hydrogen bond is anticipated to confer additional conformational rigidity to the 16-membered macrocycle.

Synthesis of gem-difluoro-avermectin derivatives: potent anthelmintic and anticonvulsant agents.

A series of gem-difluoro-avermectin derivatives was synthesized from the corresponding ketones at positions 4", 4', 13, and 23 using diethylaminosulfur trifluoride (DAST). These fluorinated avermectins exhibit potent antiparasitic activity in a new Haemonchus contortus larval assay and are equipotent to ivermectin. In addition, 23-gem-difluoro-ivermectin displays useful anticonvulsant activity in mouse models.

Eprinomectin: a novel avermectin for use as a topical endectocide for cattle.

Eprinomectin (MK-397 or 4"-epi-acetylamino-4"-deoxy-avermectin B1) is a novel avermectin selected for development as a topical endectocide for all cattle, including lactating dairy cows. Herein, we show its anthelmintic, insecticidal and miticidal activity. To determine its anthelmintic capabilities, eprinomectin was tested topically on Jersey calves at 0.

Efficacy in sheep and pharmacokinetics in cattle that led to the selection of eprinomectin as a topical endectocide for cattle.

Eprinomectin (MK-397 or 4"-epi-acetylamino-4"-deoxy-avermectin B1) is a novel avermectin selected for development as a topical endectocide for all cattle, including lactating cows. The initial efficacy assessments were made in sheep to identify subclasses of the avermectin/milbemycins that possessed inherent activity against a spectrum of nematode parasites. This included examination of several hundred analogs each given orally to a single sheep experimentally infected with a range of parasitic nematodes.