Saxena B B, Singh M, Gospin R M, Chu C C, Ledger W J
Division of Reproductive Endocrinology, Weill Medical College, Cornell University, 515 East 71st Street, S-412, New York, NY 10021, USA.
Contraception. 2004 Sep;70(3):213-9. doi: 10.1016/j.contraception.2004.02.015.
This investigation describes the synthesis of a biodegradable hydrogel composed of a core surrounded by four concentric sheaths containing dextran, copolymers of polylactide and epsilon-caprolactone. The hydrogel was impregnated with iron (II) d-gluconate dihydrate, which causes complete spermiostasis due to lipid peroxidation, ascorbic acid to increase the viscosity of the cervical mucus and mixtures of polyamino and polycarboxylic acids to sustain vaginal pH close to 4.5. The combined effects of the agents in the daily eluates of the hydrogel were efficacious up to 16 days, within 30 s, as shown by sperm penetration tests. For in vivo studies, rabbits were chosen as the experimental model because they are easy to handle and the female is always in estrus. The anterior vagina of estrous female rabbits was instilled with the hydrogel, and then inseminated with the semen from a fertile male. Postinsemination flush from the female rabbits showed that all of the sperm were dead. These observations demonstrate the potential for the development of a biocompatible, nonhormonal, intravaginal contraceptive device.
本研究描述了一种可生物降解水凝胶的合成，该水凝胶由一个核心以及围绕其的四个同心鞘组成，鞘中含有右旋糖酐、聚丙交酯和ε-己内酯的共聚物。水凝胶中浸渍了二水合葡萄糖酸亚铁，其通过脂质过氧化作用导致完全的精子停滞；浸渍了抗坏血酸以增加宫颈黏液的黏度；还浸渍了多氨基和多元羧酸的混合物以维持阴道pH值接近4.5。精子穿透试验表明，水凝胶每日洗脱液中这些药剂的联合作用在30秒内长达16天都是有效的。对于体内研究，选择兔子作为实验模型，因为它们易于操作且雌性兔子总是处于发情期。将水凝胶注入发情期雌性兔子的前阴道，然后用可育雄性的精液进行授精。雌性兔子授精后的冲洗液显示所有精子均已死亡。这些观察结果证明了开发一种生物相容性、非激素的阴道内避孕装置的潜力。
