雌酮、雌二醇、雌三醇为治疗绝经综合征的雌激素。口服常用其硫酸盐或轭合物,经体内代谢后才成为活性产物。哌嗪雌酮硫酸盐由于首过效应,需用剂量较大。而雌二醇和雌酮虽可通过非口服途径以低得多的剂量获所需治疗浓度,但雌酮轭合物在阴道给药时,雌二醇或雌酮的血浓并不高。近年来,很多学者致力于新剂型的开发以改进雌激素的体内吸收,经过对鼻腔酶活性作大量研究后发现了前体药物的释放机制,包括给药部位的酶系统作用。用前体药物 Estrone, estradiol, estriol for the treatment of estrogen in menopausal syndrome. Oral use of its sulfate or conjugate, metabolized by the body to become active product. Piperazine estrone sulfate due to the first pass effect, requiring a larger dose. While estradiol and estrone are parenterally delivered to the desired therapeutic concentrations at much lower doses, the serum concentrations of estradiol or estrone are not high when the estrone conjugate is administered vaginally. In recent years, many scholars have devoted themselves to the development of new dosage forms to improve the absorption of estrogen in vivo. After extensive research on nasal enzyme activity, the release mechanism of prodrugs, including the enzyme system of the administration site, has been discovered. With prodrugs