Novel intravaginal nanomedicine for the targeted delivery of saquinavir to CD4⁺ immune cells

Sidi Yang,^1,2 Yufei Chen,^1,2 Kaien Gu,^1,2 Alicia Dash,^1,2 Casey L Sayre,¹ Neal M Davies,¹ Emmanuel A Ho<sup>1,2

1</sup>Faculty of Pharmacy, ²Laboratory for Drug Delivery and Biomaterials, University of Manitoba, Winnipeg, MB, Canada

Abstract: The goal of this study was to develop and characterize an intravaginal nanomedicine for the active targeted delivery of saquinavir (SQV) to CD4⁺ immune cells as a potential strategy to prevent or reduce HIV infection. The nanomedicine was formulated into a vaginal gel to provide ease in self-administration and to enhance retention within the vaginal tract. SQV-encapsulated nanoparticles (SQV-NPs) were prepared from poly(lactic-co-glycolic acid)(PLGA) and conjugated to antihuman anti-CD4 antibody. Antibody-conjugated SQV-NPs (Ab-SQV-NPs) had an encapsulation efficiency (EE%) of 74.4% ± 3.7% and an antibody conjugation efficiency (ACE%) of 80.95% ± 1.10%. Over 50% of total loaded SQV was released from NPs over 3 days. NPs were rapidly taken up by Sup-T1 cells, with more than a twofold increase in the intracellular levels of SQV when delivered by Ab-SQV-NPs in comparison to controls 1 hour post-treatment. No cytotoxicity was observed when vaginal epithelial cells were treated for 24 hours with drug-free Ab-NPs (1,000 µg/mL), 1% HEC placebo gel (200 mg/mL), or 1% HEC gel loaded with drug-free Ab-NPs (5 mg NPs/g gel, 200 mg/mL of gel mixture). Overall, we described an intravaginal nanomedicine that is nontoxic and can specifically deliver SQV into CD4⁺ immune cells. This platform may demonstrate potential utility in its application as postexposure prophylaxis for the treatment or reduction of HIV infection, but further studies are required.

Keywords: nanoparticles, saquinavir, antibody conjugation, intravaginal gel, HIV/AIDS, microbicide