实验证明:由性交时射入女性阴道的活动精子数降至21%时,卵子的受精率即可降至零,这表明精子活动力降低或停止活动,即可使受孕率降低或使之不能受孕。故安全、有效,方便而易被人们接受的女用阴道内屏障性或抑、杀精子避孕药的研究,仍是当前计划生育研究中的一个重要课题。1981年 Hong 等发现心得安在体外具有抑制人类 Experiments show that: the number of sperm into the female vagina during sexual intercourse dropped to 21%, the fertilization rate of the egg can be reduced to zero, indicating that sperm motility decreased or stopped activity, you can make the pregnancy rate decreased or not Pregnancy. Therefore, it is still an important issue in current research on family planning to study the safe, effective, convenient and easily accepted vaginal barrier or suppression of spermicidal contraceptives in women. In 1981, Hong et al. Found that propranolol can inhibit human beings in vitro