Spermicidal and antifertility effects of an imbibing and soluble nonoxynol-9 diaphragm (ISND) in rabbits

Abstract

Objective To determine the minimum effective concentration (MEC) of an imbibing and soluble nonoxynol-9 (N-9) diaphragm (ISND) required for immobilisation of all spermatozoa in vitro and in vivo. The speed of semen absorbance, time of ISND to dissolution, and the antifertility effects were also investigated in rabbits.

Methods In vitro spermicidal tests with ISND were conducted using fresh semen from humans and rabbits. Spermicidal and antifertility effects were observed in vivo after the ISND was placed directly into the vagina of rabbits.

Results The MEC of N-9 required in the ISND to totally immobilise sperm within 20 seconds was 0.15 mg/ml for human sperm, and 0.5 mg/ml for rabbit sperm. The human semen was absorbed into the ISND in 45 minutes; the diaphragm dissolved in the vagina 3.5 hours later. In vivo, in rabbits, the MEC of N-9 required to immobilise sperm within five minutes of mating was 1 mg/kg in the ISND, and 10 mg/kg for the nonoxynol-9 film. The median effective dose of N-9 in the ISND was 1.07 mg/kg, whereas for the film it was 3.30 mg/kg.

Conclusion The spermicidal and antifertility activities of a low dose N-9 in the ISND were high, with properties of imbibition and solubility confirmed.

Chinese Abstract

摘要 目的 确定吸液可溶性壬丙醇醚-9(N-9)隔膜(ISND)在体内和体外使所有精子制动所需要的最低有效浓度(MEC)。同时研究了在家兔体内的精液吸收速度，ISND分解速度和避孕效果。

方法 使用了人类和家兔的新鲜精液进行ISND体外杀精试验。将ISND直接置入家兔阴道后观察ISND在体内的杀精和避孕效果。

结果 ISND使人类精液的精子在20秒内完全制动的N-9最低有效浓度为0.15 mg/ml，家兔精液中精子20秒内完全制动的N-9最低有效浓度为0.5 mg/ml。人类精液在45分钟内被吸收进ISND；隔膜于3.5小时后在阴道中分解。在家兔体内，交配5分钟内使精子制动的ISND中N-9最低有效浓度为1 mg/kg，壬丙醇醚-9膜中N-9最低有效浓度为10 mg/kg。ISND中N-9的中位有效剂量为1.07 mg/kg，N-9膜中N-9的中位有效剂量为3.30 mg/kg。

结论 ISND中低剂量N-9具有高杀精和避孕效能，同时具有已被证实的吸液可溶性。

Keywords:

• ISND
• Nonoxynol-9
• Spermicide
• Antifertility
• Diaphragm
• Rabbit

ACKNOWLEDGEMENTS

The authors are most grateful to Zhu Weiwei, MD, of the Peking Union Medical College, for reviewing the manuscript and contributing to its final presentation.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and the writing of the paper.