Assay for establishing whether microbicide applicators have been exposed to the vagina

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Article (peer-reviewed)

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Objectives: To develop an accurate, rapid, and inexpensive method for verifying vaginal applicator use. Goal: To develop a method for assessing compliance in microbicide clinical trials. Study Design: Single use Microlax applicators containing a placebo formulation either were or were not exposed to the vagina. Three assays were developed to determine whether the applicators had been used vaginally. Results: Blinded examiners were able to discern 63% of the time whether or not applicator tips had been exposed to the vagina. Optical density (to measure lactobacilli), increased in media exposed to used applicators but not in media exposed to unused applicators. When tips of applicators were stained with trypan blue, used applicators could be distinguished easily from unused applicators. Conclusion: Staining of applicator is accurate, simple, rapid, and inexpensive. This method could be be used in clinical settings in the developing world. Dying applicator tips could prove useful in excluding non-compliant subjects, analyzing data, or developing social intervention strategies to improve compliance.