EIDD-1931 Treatment Tweaks CYP3A4 and CYP2C8 in Arthritic Rats to Expedite Drug Interaction: Implication in Oral Therapy of Molnupiravir

Abstract

EIDD-1931 is the active form of molnupiravir, an orally effective drug approved by the United States Food and Drug Administration (USFDA) against COVID-19. Pharmacokinetic alteration can cause untoward drug interaction (drug-drug/disease-drug), but hardly any information is known about this recently approved drug. Therefore, we first investigated the impact of the arthritis state on the oral pharmacokinetics of EIDD-1931 using a widely accepted complete Freund's adjuvant (CFA)-induced rat model of rheumatoid arthritis (RA) after ascertaining the disease occurrence by paw swelling measurement and X-ray examination. Comparative oral pharmacokinetic assessment of EIDD-1931 (normal state vs arthritis state) showed that overall plasma exposure was augmented (1.7-fold) with reduced clearance (0.54-fold), suggesting its likelihood of dose adjustment in arthritis conditions. In order to elucidate the effect of EIDD-1931 treatment at a therapeutic regime (normal state vs arthritis state) on USFDA-recommended panel of cytochrome P450 (CYP) enzymes (CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, and CYP3A4) for drug interaction using the same disease model, we monitored protein and mRNA expressions (rat homologs) in liver tissue by western blotting (WB) and real time-polymerase chain reaction (RT-PCR), respectively. Results reveal that EIDD-1931 treatment could strongly influence CYP3A4 and CYP2C8 among experimental proteins/mRNAs. Although CYP2C8 regulation upon EIDD-1931 treatment resembles similar behavior under the arthritis state, results dictate a potentially reverse phenomenon for CYP3A4. Moreover, the lack of any CYP inhibitory effect by EIDD-1931 in human/rat liver microsomes (HLM/RLM) helps to ascertain EIDD-1931 treatment-mediated disease-drug interaction and the possibility of drug-drug interaction with disease-modifying antirheumatic drugs (DMARDs) upon coadministration. As elevated proinflammatory cytokine levels are prevalent in RA and nuclear factor-kappa B (NF-kB) and nuclear receptors control CYP expressions, further studies should focus on understanding the regulation of affected CYPs to subside unexpected drug interaction.

Figure 1

Chemical structure of molnupiravir and EIDD-1931.

Figure 2

Assessment of CFA-treated animals for induction of arthritis before pharmacokinetic studies of EIDD-1931. Changes in paw swelling behavior on 9th day (A); representative radiological images of left hind paw for the normal state (B) and the arthritis state (C); H&E-stained images of bone joints in the normal state (D) and the arthritis state (E), where arrow indicators dictate as follows: black—desquamation of epithelial cells, blue—synovial proliferation, and green—pannus formation. Data are represented as mean ± SEM (n = 5). Data were compared between the normal state and arthritis state. Statistical significance: p <*0.05/**0.01/***0.001.

Figure 3

Mean plasma concentration vs time profile (A) and pharmacokinetic parameters (B) of EIDD-1931 after oral administration in rats under the normal state and arthritis state. Data are presented as mean ± SEM (n = 5). Data were compared between the normal state and arthritis state. Statistical significance: *p <0.05.

Figure 4

Western blot analysis with densitometry data for the protein expressions in the hepatic tissues of the animals in the different study groups using β-actin as a loading control: (A) CYP1A2, (B) CYP2B6, (C) CYP2C8, (D) CYP2C11, (E) CYP2C19, (F) CYP2D6, and (G) CYP3A4. G1 represents the control group (normal state), G2 represents the treated group (normal state), G3 represents the control group (arthritis state), and G4 represents the treated group (arthritis state).

Figure 5

RT-PCR analysis for the mRNA expressions in the hepatic tissues of the animals in the different study groups using GAPDH as a loading control: (A) CYP1A2, (B) CYP2B1, (C) CYP2B2, (D) CYP2C11, (E) CYP2C13 (F) CYP2D1, (G) CYP3A1, (H) CYP3A18, and (I) CYP3A9. G1 represents the control group (normal state), G2 represents the treated group (normal state), G3 represents the control group (arthritis state), and G4 represents the treated group (arthritis state).

Figure 6

Pictorial representation of the impact of EIDD-1931 in the arthritis state toward drug interaction.