Augmented Inhibition of CYP3A4 in Human Primary Hepatocytes by Ritonavir Solid Drug Nanoparticles.
Ritonavir is a protease inhibitor utilized primarily as a pharmaco-enhancer with concomitantly administered antiviral drugs including other protease inhibitors. However, poor tolerance, serious side effects, and toxicities associated with drug-drug interactions are common during exposure to ritonavir. The aim of this work was to investigate the impact of nanoformulation on ritonavir pharmacological properties. Emulsion-templated freeze-drying techniques were used to generate ritonavir (10 wt %) solid drug nanoparticle formulations. A total of 68 ritonavir formulations containing various mixtures of excipients were assessed for inhibition of CYP3A4 in baculosomes and primary human hepatocytes. Accumulation and cytotoxicity were assessed in HepG2 (hepatocytes), Caco-2 (intestinal), THP-1 (monocytes), A-THP-1 (macrophage), and CEM (lymphocytes). Transcellular permeation across Caco-2 cells was also assessed. From 68 solid drug nanoparticle formulations tested, 50 (73.5%) for baculosome and 44 (64.7%) for human primary hepatocytes exhibited enhanced CYP3A4 inhibition relative to an aqueous ritonavir solution. Sixty-one (89.7%) and 49 (72%) solid drug nanoformulations had higher apical to basal permeation across Caco-2 cells than aqueous solution of ritonavir after 60 and 120 min, respectively. No significant difference in cellular accumulation was observed for any solid drug nanoparticle for any cell type compared to aqueous ritonavir. However, incubation with the vast majority of solid drug nanoparticle formulations resulted in lower cytotoxicity of ritonavir than detected with an aqueous solution. These data provide in vitro proof of concept for improved inhibition of CYP3A4 by ritonavir through formation of solid drug nanoparticles. Nanodispersions also showed enhanced permeability across Caco-2 cells lower cytotoxicity across hepatic, intestinal, and immune cell types compared to an aqueous solution of ritonavir.
Department of Molecular and Clinical Pharmacology, University of Liverpool , Block H, 70 Pembroke Place, Liverpool L69 3GF, U.K.
Philip
P
Martin
Department of Chemistry, University of Liverpool , Crown Street, Liverpool L69 3BX, U.K.
Marco
M
Giardiello
Department of Chemistry, University of Liverpool , Crown Street, Liverpool L69 3BX, U.K.
Tom O
TO
McDonald
Department of Applied Sciences, University of Northumbria at Newcastle , Ellison Building, Newcastle NE1 8ST, U.K.
Darren
D
Smith
Department of Molecular and Clinical Pharmacology, University of Liverpool , Block H, 70 Pembroke Place, Liverpool L69 3GF, U.K.
Marco
M
Siccardi
Department of Chemistry, University of Liverpool , Crown Street, Liverpool L69 3BX, U.K.
Steven P
SP
Rannard
Department of Molecular and Clinical Pharmacology, University of Liverpool , Block H, 70 Pembroke Place, Liverpool L69 3GF, U.K.
Andrew
A
Owen
D018938:Caco-2 Cells / Q000187:drug effects; D051544:Cytochrome P-450 CYP3A / Q000187:drug effects / Q000378:metabolism; D065692:Cytochrome P-450 CYP3A Inhibitors / Q000008:administration & dosage / Q000494:pharmacology*; D016503:Drug Delivery Systems; D017320:HIV Protease Inhibitors / Q000008:administration & dosage / Q000494:pharmacology*; D056945:Hep G2 Cells / Q000187:drug effects; D022781:Hepatocytes / Q000187:drug effects*; D006801:Humans; D053758:Nanoparticles / Q000008:administration & dosage*; D019438:Ritonavir / Q000008:administration & dosage / Q000494:pharmacology*
D065692:Cytochrome P-450 CYP3A Inhibitors; D017320:HIV Protease Inhibitors; D051544:Cytochrome P-450 CYP3A; C510163:CYP3A4 protein, human; D019438:Ritonavir
CYP3A4; hepatocytes; nanoparticles; pharmaco-enhancer; ritonavir