A Tunable, Biodegradable, Thin-Film Polymer Device as a Long-Acting Implant Delivering Tenofovir Alafenamide Fumarate for HIV Pre-exposure Prophylaxis

Pharm Res. 2016 Jul;33(7):1649-56. doi: 10.1007/s11095-016-1904-6. Epub 2016 Mar 14.


Purpose: The effectiveness of Tenofovir based HIV pre-exposure prophylaxis (PrEP) is proven, but hinges on correct and consistent use. User compliance and therapeutic effectiveness can be improved by long acting drug delivery systems. Here we describe a thin-film polymer device (TFPD) as a biodegradable subcutaneous implant for PrEP.

Methods: A thin-film polycaprolactone (PCL) membrane controls drug release from a reservoir. To achieve membrane controlled release, TAF requires a formulation excipient such as PEG300 to increase the dissolution rate and reservoir solubility. Short-term In vitro release studies are used to develop an empirical design model, which is applied to the production of in vitro prototype devices demonstrating up to 90-days of linear release and TAF chemical stability.

Results: The size and shape of the TFPD are tunable, achieving release rates ranging from 0.5 to 4.4 mg/day in devices no larger than a contraceptive implant. Based on published data for oral TAF, subcutaneous constant-rate release for HIV PrEP is estimated at <2.8 mg/day. Prototype devices demonstrated linear release at 1.2 mg/day for up to 90 days and at 2.2 mg/day for up to 60 days.

Conclusions: We present a biodegradable TFPD for subcutaneous delivery of TAF for HIV PrEP. The size, shape and release rate of the device are tunable over a >8-fold range.

Keywords: HIV pre-exposure prophylaxis; antiretroviral; biodegradable implant; membrane controlled release; polycaprolactone; tenofovir alafenamide fumarate.

MeSH terms

  • Adenine / analogs & derivatives*
  • Adenine / chemistry
  • Adenine / pharmacology
  • Alanine
  • Anti-HIV Agents / chemistry
  • Anti-HIV Agents / pharmacology
  • Biodegradable Plastics / chemistry*
  • Chemistry, Pharmaceutical / methods
  • Delayed-Action Preparations / chemistry
  • Delayed-Action Preparations / pharmacology
  • Drug Delivery Systems / methods
  • Drug Liberation / physiology
  • Fumarates / chemistry*
  • HIV-1 / drug effects*
  • Particle Size
  • Polyesters / chemistry
  • Polymers / chemistry*
  • Pre-Exposure Prophylaxis / methods
  • Solubility
  • Tenofovir / analogs & derivatives


  • Anti-HIV Agents
  • Biodegradable Plastics
  • Delayed-Action Preparations
  • Fumarates
  • Polyesters
  • Polymers
  • polycaprolactone
  • Tenofovir
  • tenofovir alafenamide
  • Adenine
  • Alanine