Development of a Wearable Injection System for Delivery of Highly Viscous HIV Medication

Current HIV treatment options are effective, yet require strict adherence to the designated regimen. Having to follow a daily pill or monthly injection treatment regimen is a significant barrier to treatment, a fact noted by studies into the efficacy and reach of antiretroviral treatments. HIV disproportionately affects already-marginalized communities, and many of the people in the United States living with HIV experience homelessness, mental health disorders, substance abuse issues, or a combination of those. A large number of these people would greatly benefit from the ability to live symptom-free with just a single yearly dose. However, a dose that will maintain viral suppression for a year requires a very high drug load. Additionally, it must be administered in such a way that it can slowly release into the patient, such as an injection into fatty tissue that allows for incremental release of the drug into the body.
Gilead is developing a highly concentrated HIV medication, and has asked us to explore a wearable injection system for the annual delivery of this medication. We were required to inject 6 milliliters of medication, which has a viscosity of 1200 centipoise, in under two hours. After exploring various options, we found success with a low-speed peristaltic pump. Our final design uses a stepper motor to drive the pump. Keeping in mind that our primary users are patients, we opted for this configuration to have greater flexibility to modify our device’s form factor and make it more user-friendly.
Our testing indicates that our final device is reliable throughout a two hour injection of 1200 centipoise fluid, maintaining a flow rate of 0.052 milliliters per minute through a 25 gauge needle, and that our chosen power source of 4 AAA batteries provides enough charge for two injection cycles. This achievement addresses the challenge of delivering high-viscosity medications, offering a portable, efficient, and patient-friendly solution for long-term treatment regimens.