Short Communication: Bioequivalence of Tenofovir Component of Tenofovir/Rilpivirine/Emtricitabine in Digital Pills.

Digital pills, gelatin capsules with radiofrequency transmitters activated by stomach chloride ions, directly measure antiretroviral therapy adherence. In individuals with substance use disorders and HIV, real-time nonadherence detected by digital pills creates a platform to deliver substance use and adherence interventions. In this study, we determined the bioequivalence of tenofovir (TFV), administered as tenofovir disoproxil fumarate (TDF) in healthy human volunteers administered a commercial drug product and a digital pill formulation. We adhered generally to the US FDA Analytical Procedures and Methods for Validation for Drugs and Biologics guidelines. Ten HIV-uninfected adults without reported allergy to TFV, emtricitabine, or rilpivirine were enrolled. Participants ingested a digital pill containing TDF/emtricitabine/rilpivirine. Peripheral venous blood samples were collected at 0.5, 1, 2, 4, 8, and 24 h postingestion. After a 14-day washout period, the same participants ingested Complera™. Serial venous blood samples were collected using the same protocol as the digital pill. Liquid chromatography/mass spectrometry was used to determine a maximum concentration (Cmax), area under curve from time zero to last measured concentration (AUCo-t), and area under curve from time zero to infinity (AUCoo) of TFV. Ten participants with an average age of 27 and body mass index of 25.4 successfully completed the study. Predose TFV was undetectable before the second administration of Complera confirming adequate washout period after ingestion of the digital pill. The geometric means of AUCo-t, AUCoo, and Cmax for test and reference products were within the 95% confidence intervals and, therefore, bioequivalent. TFV overencapsulated in digital pills are bioequivalent to TFV in commercial formulations.