Evaluation of a vaginal moisturizer in baboons with decreasing ovarian function

Decrease of estrogen concentrations in postmenopausal women leads to many urogenital problems including vaginal dryness, atrophy, stenosis, itching, and irritation, along with sexual dysfunction. Systemic estrogen replacement is effective in many women but may not be effective in others because estrogen therapy may be contraindicated for medical reasons. The reproductive tract in nonhuman female primates has been used successfully as a model for a variety of research including, but not limited to, anatomy and physiology, reproduction, cancer, infectious disease, and menopause. The baboon is especially valuable because of the similarity of its menstrual cycle to women's, prior research with this animal, and its adaptability to captivity. A nonhormonal, nonsystemic, bio-adhesive vaginal moisturizer was evaluated in baboons as a possible alternative to hormonal therapy for vaginal symptoms due to a decrease in estrogen concentrations. Eight baboons with decreasing ovarian function were used in a two-part study to evaluate vaginal health with pliability, elasticity, mucosal secretion, pH, and histologic features as criteria. The first study involved a single intravaginally administered dose of test product, with evaluation at 20 min and 24 h later. The second study consisted of five doses given at 24-h intervals, with daily evaluations for 9 consecutive days. There was marked improvement in vaginal pliability, elasticity, and secretions, with decreased pH and thickness of the vaginal epithelium. These effects appeared 1 or 2 days after drug administration, reached the maximum on day 4, and mostly decreased by day 8. However, increased secretions, vaginal elasticity, and vacuolization of the epithelium in biopsy specimens persisted to the last day of observation. The study results indicate the efficacy of the test product and the value of the baboon as a model to study decreasing ovarian function and vaginal health.