Enema Use and Acceptability in HIV Negative Men Who Have Sex With Men

Research participants who are deemed eligible after screening will return for a baseline evaluation. The baseline visit includes clinical evaluation and colon tissue collection, as well as a Baseline Behavioral Questionnaire (BBQ). The BBQ will be administered by Computer Assisted Self-Interview (CASI). Participants may complete the web-based CASI in the privacy of their own home. Following the baseline visit, participants will be randomized into one of three groups. Each group will receive enemas of varying osmolality (molecule concentrations) in a different sequence according to study stage. During each stage of enema test product use participants will receive a single inpatient dose followed by three outpatient doses to be used in the context of Receptive Anal Intercourse (RAI). This study will involve 3 stages of enema test product use. Each stage is identical, with the exception of the enema osmolality. Each stage includes an inpatient period and an outpatient period. The time period between stages 1, 2, and 3 will be approximately 2-6 weeks to allow for a recovery period, opportunities for product use, and appointment availability. The participant's inpatient portion of the study will take place as scheduling permits after the at-home enema use is complete. During each stage, the participant is admitted to the inpatient unit for \<48 hours, placed on a clear liquid diet, and has an interval medical history and directed physical exam. The following day the 125ml study enema is radiolabeled and administered to the participant. Over an approximately 25 hour time period, the participant will undergo pharmacokinetic studies involving blood drawing, colon tissue sample collection by flexible sigmoidoscopy, and imaging by Single Photon Emission Computed Tomography/ paired with x-ray Computed Tomography (SPECT/CT). The participant will then be discharged home with 3 doses of study enema. Participants will be instructed to allow for an approximately 72 hour recovery period (to ensure healing of the colon tissue biopsy sites) prior to initiating use of the study product on an outpatient basis, if applicable. Subjects will be encouraged to use the study product on 3 separate occasions in the context of RAI. As with standard HIV counseling, participants will be encouraged to use condoms. After each outpatient use the subject will complete a Brief Acceptability Questionnaire (BAQ). Then at the end of each stage of enema test article use, the subject will complete a Product Acceptability Questionnaire (PAQ). Study Exit Interview At completion of all 3 stages the participant will complete an Overall Product Preference Questionnaire (OPPQ) administered by CASI followed by and in-depth interview.