Intravaginal flux controlled pump for sustained release of macromolecules

Ryan S. Teller, Rachna Rastogi, Todd J. Johnson, Michael J. Blair, Robert W. Hitchcock, Patrick F. Kiser*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


Purpose: To design a flux controlled pump (FCP) capable of 30-day, controlled release of macromolecules to the vaginal mucosa.

Methods: The FCP is composed of a single chamber fabricated from a rigid thermoplastic with orifices and encloses a pellet of water-swellable polymer containing the drug substance. We performed testing both in vitro and in rabbits. To ensure vaginal retention in the rabbit, we designed and attached an oval shape-memory polyether urethane retainer to the FCP allowing for long-term intravaginal evaluation of a solid dosage form without invasive surgical implantation.

Results: The orifices and swelling properties of the polymer pellet control water entry for polymer hydration and expansion, and subsequent extrusion of the drug-containing gel from the orifice. A FCP device containing a pellet composed of hydroxypropyl cellulose compounded with a model macromolecule, achieved controlled in vitro release for 30 days with an average release rate of 24±2 μg/day (mean ± SD) and range of 16 to 42 μg/day. We observed a slightly lower average release rate in vivo of 20±0.6 μg/day (mean±SD).

Conclusions: The size of the orifice and nature of the swelling polymer controls the hydration rate and thereby macromolecule release rate and duration from this FCP.

Original languageEnglish (US)
Pages (from-to)2344-2353
Number of pages10
JournalPharmaceutical Research
Issue number9
StatePublished - May 2 2014


  • in vivo evaluation
  • macromolecules
  • non-surgical implantation
  • vaginal delivery

ASJC Scopus subject areas

  • Biotechnology
  • Molecular Medicine
  • Pharmacology
  • Pharmaceutical Science
  • Organic Chemistry
  • Pharmacology (medical)


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