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 increase lipophilicity by esterification of the C-terminal carboxyl group and/or acylation of the phenolic hydroxyl group on Tyr1. Antinociceptive activity was evaluated after subcutaneous or oral administration using the mouse tail pressure test. As a result, increased antinociceptive activity after oral administration as well as an improved ED50(p.o.)/ED50(s.c.) ratio, which is an indicator of oral bioavailability, were found for some compounds. With regard to the improvement of bioavailability, derivatives with acylation of the phenolic hydroxyl group on Tyr1 showed better results than derivatives with esterification of the C-terminal carboxyl group. In particular, an ED50(p.o.)/ED50(s.c.) ratio equivalent to that of morphine was found for an acetylated derivative, Nα-1-iminoethyl-Tyr(COMe)-D-MetO-Phe-MeβAla-OH (7a), as well as for a methoxycarbonylated derivative, Nα-1-iminoethyl-Tyr(CO2Me)-D-MetO-Phe-MeβAla-OH (7l).
为了提高地莫芬四肽类似物Nα-1-亚
氨乙基-
酪氨酸-
D-甲氧基甲
硫氨酸-苯丙
氨酸-甲基β丙
氨酸-OH(III)的口服
生物利用度,该化合物在口服后具有强大的镇痛活性,通过对其C端羧基和/或
酪氨酸1上的
酚羟基进行酯化或酰化,合成了多种衍
生物以增加其脂溶性。利用小鼠尾部压力测试,通过皮下或口服途径给药后评估其镇痛活性。结果发现,部分化合物在口服给药后显示出增强的镇痛活性,并且ED50(p.o.)/ED50(s.c.)比值有所改善,这一比值是口服
生物利用度的指标。在改善
生物利用度方面,
酪氨酸1上的
酚羟基被酰化的衍
生物比C端羧基被酯化的衍
生物效果更好。特别是,乙酰化衍
生物Nα-1-亚
氨乙基-
酪氨酸(COMe)-
D-甲氧基甲
硫氨酸-苯丙
氨酸-甲基β丙
氨酸-OH(7a)和甲氧基羰基化衍
生物Nα-1-亚
氨乙基-
酪氨酸(CO2Me)-
D-甲氧基甲
硫氨酸-苯丙
氨酸-甲基β丙
氨酸-OH(7l)的ED50(p.o.)/ED50(s.c.)比值与
吗啡相当。