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02420_1 INTRA-VAGINAL DISTRIBUTION OF CELLULOSE SULFATE Barnhart, K* Introduction: A microbicide formulation of 6% sodium cellulose sulfate (CS) has been demonstrated to be safe for human subjects, although the optimal applied volume of gel is not known. Larger volumes (5 ml) of gel lead to increased leakage, and smaller volumes (2.5 ml) of gel may provide insufficient vaginal epithelial coverage. Given concern that a dose volume of 2.5 ml may not provide sufficient vaginal coverage to prevent sexually transmitted diseases, including HIV, this study was performed to evaluate intravaginal gel spread and gel leakage in patients who used 2.5 ml and 3.5 ml dose volumes of CS. Methods: Blinded crossover study of CS gel delivered in 2.5 ml and 3.5 ml volumes to 6 women, three parous and three nulligravid. Each woman was imaged using three-dimensional MRI with gadolinium chelate contrast added to the gel.. Imaging was performed at baseline, and at 5, 20, 35 and 50 minutes after product insertion. Each woman used both gel volumes twice: once with ambulation following insertion and once without ambulation. The sequence was determined by randomization. Results: Most linear gel spread took place in the first five minutes after insertion, although some continued spread was seen when ambulation took place. Lateral spreading appeared to continue after linear spreading had slowed or stopped. Ambulation also increases gel spread. At times greater than 5 minutes, ambulation had a greater effect on gel distribution than did gel volume. The degree of spreading achieved at 5 and 20 minutes was approximately 60% of both linear distance and surface contact in any group. By 50 minutes, coverage ranged from 53.1% to 84.5% of the linear distance covered and surface contact ranged from between 61.7% - 85.9%. Using a larger volume of gel increased linear spreading but had less consistent effects on lateral spread as measured by surface contact. Within ambulating groups, use of the larger volume increased linear spreading by 4-23% at each time point and increased surface contact by 5-46% at all time points. The greatest linear spreading (49.2 mm) and surface contact (85.9%) 50 minutes after product insertion were in the group of women who used 3.5 ml of gel and ambulated. There was no clear pattern of effect by parity. Most of the women had bare spots in coverage, particularly in the proximal vagina. Leakage was not a severe problem in any of the groups. Conclusions: The spreading of CS in the absence of intercourse did not result in complete vaginal coverage, even when observed 50 minutes after product insertion. The use of 3.5 ml compared with 2.5 ml, and the practice of ambulation, generally increased gel spread. Results are generally consistent with other MRI studies of vaginal products. This research was funded by CONRAD. Dr. Kurt T. Barnhart |
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