Complex sentence: Triazolam self-administration has not been studied in rodents, but five such studies have been conducted in non-human primates, three of which involved in the intravenous (IV) route.
Split into simpler sentences: Triazolam self-administration has not been studied in rodents, but five such studies have been conducted in non-human primates. Three of the studies involved in the intravenous (IV) route.