COMPARATIVE SPERMICIDAL PERFORMANCE OF IODINATED AND NON-IODINATED CONTRACEPTIVE FORMULATIONS OF NONOXYNOL-9 CO-PRECIPITATED WITH POLYVINYLPYRROLIDONE

The objective of this study was to evaluate the spermicidal qualities of various combinations of nonoxynol-9 (N-9; whole molecule = oligomer s 1-18) and its isolated fractions (oligomers 8-20, 4-6 and 1-3), co-p recipitated with non-iodinated and/or iodinated (I-o) polyvinylpyrroli done (PVP) as possible vaginal contraceptives. Spermicidal qualities o f known equimolar concentrations of various combinations of PVP/N-9 an d PVP-I-o/N-9 were tested via a modified Sander-Cramer test (SCT) usin g human spermatozoa. Spermicidal agents and semen samples were mixed 1 :1 (v/v) and evaluated for sperm viability. Spermicidal activity was r eported as the minimal concentration (mu g/mL) of spermicide capable o f killing all spermatozoa within 20 sec after exposure to the spermici de. The spermicidal activity of PVP/N-9 and PVP-I-o/N-9 preparations c ontaining N-9 oligomers 1-18 and/or 8-10 was similar, and these prepar ations were more efficient in killing the spermatozoa than the ones co ntaining N-9 oligomers 4-6 and 1-3. Polyvinylpyrrolidone proved to be an effective vehicle for PVP/N-9 and PVP-I-o/N-9 preparations, especia lly those containing N-9 oligomers 4-6 and 1-3. Incorporation of I-o i nto the spermicidal preparations brought about additional efficacy. Th e current findings could be of clinical significance in future studies when preparing and delivering those selected co-precipitates vaginall y.