A Dose Ranging Pharmacokinetic Evaluation of IQP-0528 Released from Intravaginal Rings in Non-Human Primates

Jonathan T. Su, Ryan S. Teller, Priya Srinivasan, Jining Zhang, Amy Martin, Samuel Sung, James M. Smith, Patrick F. Kiser*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


Purpose: Design of intravaginal rings (IVRs) for delivery of antiretrovirals is often guided by in vitro release under sink conditions, based on the assumption that in vivo release will follow a similar release profile. Methods: We conducted a dose-ranging study in the female reproductive tract of pigtail macaques using matrix IVRs containing IQP-0528, a poorly soluble but highly potent antiretroviral drug with an IC90 of 146 ng/mL. These IVRs consisted of drug-loaded segments, 15.6% IQP-0528 in Tecoflex 85A, comprising either all, half, or a quarter of the entire ring. Results: In vitro release under sink conditions demonstrates loading-proportional release, with a cumulative 30-day release of 48.5 ± 2.2 mg for our 100% loaded ring, 24.8 ± .36 mg from our 50% loaded ring, and 13.99 ± 1.58 mg from our 25% loaded ring. In vivo, while drug concentration in vaginal fluid is well in excess of IQP-0528’s EC90, we find no statistical difference between the different ring loadings in either swab drug levels or drug released from our rings. Conclusions: We show that in vitro release may not accurately reflect in vivo release, particularly for poorly soluble drugs. All tested loadings of our IVRs are capable of delivering IQP-0528 well in excess of the IC90.

Original languageEnglish (US)
Pages (from-to)2163-2171
Number of pages9
JournalPharmaceutical Research
Issue number10
StatePublished - Oct 1 2017


  • IQP-0528
  • intravaginal rings
  • macaque
  • pharmacokinetics

ASJC Scopus subject areas

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


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