MEASUREMENT AND MODULATION OF NONOXYNOL-9 DIFFUSION AND BIOACTIVITY AGAINST SPERMATOZOA IN HUMAN CERVICAL-MUCUS

Assays of sperm penetration into cervical mucus, in the configuration of double-ended tests (DETs), are an accepted format for evaluating th e efficacy of sperm-directed contraceptives in mucus. In order to dist inguish relative contributions of compound permeation into, and com po und bioactivity within, cervical mucus with respect to vanguard sperm penetration measured in DETs, direct measurements were made of concent ration profiles of the spermicide nonoxynol-9 (N9) after diffusion int o mucus-filled capillary tubes. N9 was dissolved in two different deli very solutions, deionized water and saline, in an attempt to exploit a Donnan-mediated swelling of mucus for enhanced delivery of the spermi cide. Average diffusion coefficients, 7 and 5 x 10(-7) cm(2)/sec for N 9-water and N9-saline, respectively, indicate that the diffusion of NP , a surfactant material, is governed by the size of the N9 micelle rat her than the molecular size, in the concentration range typically foun d in commercial preparations. Permeation of N9 into mucus was signific antly greater for water versus saline as delivery solution, although t he difference was slight. A more pronounced difference between the two treatments was found in DET results, due to an osmotic and/or pH acti vity of the delivery solution itself against sperm in mucus. (C) 1997 Elsevier Science Inc.