Concentrations Of Nonoxynol-9 Research Articles

Diffusion of Nonoxynol-9 Into Human Semen In Vitro

The diffusion of [ 125I]-nonoxynol-9 into human semen was investigated in vitro before and after liquefaction. No significant difference was found in the distribution of [ 125I]-nonoxynol-9 within columns of preliquefied semen, liquefied semen, seminal plasma, or water after ≤120 minutes of diffusion; however, significantly more nonoxynol-9 entered preliquefied semen. The concentration of nonoxynol-9 that entered semen in vitro was greater than its ED 100 and the bioavailability was confirmed by demonstration of the retention of spermicidal action. These results indicate that the gel state of preliquefied semen does not inhibit the entry or action of nonoxynol-9 and, consequently, sperm would be exposed to it immediately when it is used in vivo as a vaginal spermicide.

Characterization of in-Vitro Spermicidal Activity of Chelating Agent against Human Sperm

The effect of ethylenediaminetetraacetic acid (EDTA), a cationic chelating agent, on sperm motility and sperm penetration through cervical mucus was evaluated. EDTA exerted a relatively mild dose-dependent effect on sperm motility. Total loss of sperm motility (EC100) was achieved at a concentration of about 5.0mg/mL of EDTA, which is much greater than the 200 µg/mL concentration of Nonoxynol-9 (N-9). EDTA salts, such as EDTA-Na2 and EDTA-Na4, showed weak spermicidal activity, while EDTA-K2 and EDTA-Ca had no spermicidal activity at concentrations up to 5.0mg/mL. EDTA appeared to decrease the in vitro percentage of motile sperm as a function of exposure time. EDTA completely impeded the penetration of sperm into cervical mucus at a concentration much lower than that for 100% inhibition of sperm motility in semen. In the presence of 500–3200 µg/mL extra calcium, the first-order rate constant for sperm immobilization, which was derived from the slopes of a relative sperm motility curve, was reduced by 38.9–55.6% of the control and was inversely proportional to calcium concentration. After exposure to EDTA, the calcium ion concentration in semen was reduced as a function of EDTA concentration, which yielded a linear reduction of sperm motility. A decrease of approximately 65% in calcium ion concentration in semen seemed to be the threshold at which total loss of sperm motility occurred. Calcium ion was shown to play an essential role in regulating sperm motility in semen, and EDTA was demonstrated to exert spermicidal activity by modulating calcium ion concentration in semen.

Influence of the spermicidal compound nonoxynol-9 on the adhesion of E. coli to human epithelial cells

Two type I piliated strains of Escherichia coli were cultured in medium supplemented with physiologically used concentrations of the spermicidal compound nonoxynol-9. Their ability to adhere to HeLa cells in tissue culture was found to increase significantly (p<0.05). For strain 12313, there was a 2.3- and 1.9-fold increase when cultured in 5% and 12.5% (w/v) nonoxynol-9 respectively, and adhesion of strain 12269 increased by 1.7 times after growth in 12.5% (w/v) nonoxynol-9. The increased adhesion was accompanied by loss of mannose-sensitive yeast agglutination and hemagglutination. The absence of type I piliation was confirmed by electron miscroscopy and was accompanied by a decrease in cell surface hydrophobicity. The ability of E. coli to grow in high concentrations of nonoxynol-9, combined with increased adhesion to human epithelial cells in vitro, may contribute to the increased incidence of E. coli urinary tract infection seen in women using diaphragms and spermicidal preparations for contraception.

Comparison of the action of nonoxynol-9 and chlorhexidine on sperm

The effect on sperm motility of nonoxynol-9 chlorhexidine diacetate was compared in semen and cervical mucus. Both compounds had similar spermicidal potency in semen, abolishing sperm motility within 3 minutes at 0.5 mg/ml. When these compounds were allowed to diffuse into mucus, the subsequent survival of sperm in the mucus was different. Restricted penetration and loss of motility occurred rapidly after treatment with 0.1 mg/ml chlorhexidine, whereas sperm survived normally in mucus after prolonged contact with 200 mg/ml chlorhexidine. When the compounds were mixed directly with the mucus before sperm penetration was attempted, chlorhexidine still immobilized sperm, but concentrations of nonoxynol-9 that would be spermicidal in semen had no effect in mucus.