Usability of STAR Particles in Healthy Volunteers: A Pilot Study

The goal of this study is to identify the most efficacious pressure of administration and the minimum number of rubbing cycles necessary to perforate the stratum corneum (the outermost layer of the skin).

Many medical conditions are treated through the topical application of a therapeutic compound formulated into a gel, cream, ointment, or lotion (e.g., eczema, psoriasis, actinic keratosis, cutaneous warts). This is especially true in dermatology, in which the skin is often the primary site of action. Topicals (i.e., drugs applied to the skin's surface) allow patients to easily self-apply these therapies without the need for painful or difficult-to-use medical technologies (e.g., hypodermic needles) or the risks associated with systemic exposure to a drug (e.g., oral, intravenous, or intramuscular administration).

Despite the advantages associated with topical delivery, the skin serves as a barrier to the transport of most external compounds. There are several techniques to overcome the skin barrier. Several studies have been conducted to increase skin permeability using various methods, including chemical, biochemical, and physical approaches. However, chemical and biochemical methods do not appear to be broadly useful for the delivery of large molecule therapeutics (e.g., peptides, proteins, genetic material) across the skin. STAR particles are millimeter-scale particles with micron-scale projections made of biocompatible materials that painlessly disrupt the stratum corneum. As STAR particles are rubbed on the skin, their microscopic projections create micron-scale pores in the stratum corneum to increase skin permeability to topical compounds independent of physicochemical properties. After the arms of the STAR particle puncture the skin, the elastic forces of the skin push the particles out. The first 10 participants will receive the 8 interventions (different application pressures) plus the control (Site and treatment will not be randomly assigned to the arm) by the investigator. In addition, two applications of STAR particles will be applied to one of the hands. After these participants have completed the study, an interim analysis will be performed. At this point, a decision will be made by the investigator to determine if changes in STAR particle administration will be implemented for the next 10 participants.