EFFECTS OF CHOLIC-ACID AND PROTECTAID FORMULATIONS ON HUMAN SPERM MOTILITY AND ULTRASTRUCTURE

Cholic acid (sodium cholate) and the other active ingredients of F-5 g el preparations in use for the impregnation of a new vaginal sponge (P rotectaid(R)) with contraceptive and anti-sexually transmitted disease properties, were assessed for their effects on human sperm motility a nd ultrastructure. Cholic acid (CA) produced an inhibition of motility which was both dose- and time-dependent. A complete suppression of mo tility was obtained at 30 s by a CA concentration of 1.25%. Nonoxynol- 9 (NX9) compared with benzalkonium chloride (BZC) showed no significan t difference at the concentration required (0.025%) to give a total in hibition of sperm motility after exposure for 30 s. The addition of F- 5A gel containing 0.5% of each one of the spermicide ingredients (CA, NX9 and BZC) produced the total suppression of sperm motility within 3 0 s at a dilution of 1/50. Another preparation, F-5B gel, containing t he spermicide ingredients at different concentrations (1.25% CA, 0.125 % NX9 and 0.05% BZC) produced this same effect with a 1/10 dilution. E xposure of semen to a CA concentration of 1.25% or to 1/10 dilutions o f F-5A gel for 30 s led to profound changes of sperm ultrastructure st udied by scanning (SEM) and transmission (TEM) electron microscopy. SE M and TEM findings indicate that CA acts as a spermicide through its ' natural detergent' properties, damaging the outer plasma membrane of s perm cells. Protectaid formulations affect sperm motility and viabilit y in a similar way.