The effectiveness of any biomedical prevention technology relies on both biological efficacy and behavioraladherence. Microbicide trials have been hampered by low adherence, limiting the ability to draw meaningfulconclusions about product effectiveness. Central to this problem may be an inadequate conceptualization of howproduct properties themselves impact user experience and adherence. Our goal is to expand the current microbicidedevelopment framework to include product ‘‘perceptibility,’’ the objective measurement of user sensoryperceptions (i.e., sensations) and experiences of formulation performance during use. For vaginal gels, a setof biophysical properties, including rheological properties and measures of spreading and retention, may criticallyimpact user experiences. Project LINK sought to characterize the user experience in this regard, and tovalidate measures of user sensory perceptions and experiences (USPEs) using four prototype topical vaginal gelformulations designed for pericoital use. Perceptibility scales captured a range of USPEs during the productapplication process (five scales), ambulation after product insertion (six scales), and during sexual activity (eightscales). Comparative statistical analyses provided empirical support for hypothesized relationships between gelproperties, spreading performance, and the user experience. Project LINK provides preliminary evidence for theutility of evaluating USPEs, introducing a paradigm shift in the field of microbicide formulation design. Wepropose that these user sensory perceptions and experiences initiate cognitive processes in users resulting inproduct choice and willingness-to-use. By understanding the impact of USPEs on that process, formulationdevelopment can optimize both drug delivery and adherence.
