Nasal absorption of 17 alpha-ethinyloestradiol in the rat

The bioavailability of 17 alpha-ethinyloestradiol was determined after intravenous, nasal, and intraduodenal, administration in the rat. The results showed that the bioavailability of nasally-administered and intraduodenally-administered drug was 80-85, and 15-25%, respectively, of that following intravenous administration. The study demonstrates that the nasal route for the administration of 17 alpha-ethinyloestradiol is superior to the oral route in this species, and may thus provide an alternative for the administration of this drug at lower doses.