Synthesis and antinociceptive activity of orally active opioid peptides: Improvement of oral bioavailability by esterification
To improve the oral bioavailability of a dermorphin tetrapeptide analog, Nα-1-iminoethyl-Tyr-D-MetO-Phe-MeβAla-OH (III), 1) which has a potent analgesic activity after oral administration, various derivatives were synthesized to incr