Development and evaluation of cepharanthine-β-cyclodextrin inclusion complex oral tablets for prevention and treatment of COVID-19 lung injury

Abstract

The symptoms of coronavirus disease 2019 (COVID-19) range from severe lung disease to milder manifestations, such as cough and throat irritation. As a bisbenzylisoquinoline alkaloid, cepharanthine (CEP) has various pharmacological properties, such as antifibrotic, anti-inflammatory, antioxidant, and antiviral effects. However, its poor solubility and low bioavailability hinder subsequent drug development. Inclusion complex technology is a well-established drug delivery method that improves drug bioavailability. Therefore, in our study, we encapsulated CEP with β-cyclodextrin and formulated it into oral tablets. Oral tablets can be absorbed through sublingual and buccal mucosa, improving CEP bioavailability, facilitating convenient dosing, and thereby enhancing its therapeutic efficacy. The cepharanthine-β-cyclodextrin (CEP-β-CD) inclusion complex was prepared using the co-grinding method. It was characterized using scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and differential scanning calorimetry to assess its physicochemical properties. Subsequently, the quality of the CEP-β-CD oral tablets was evaluated according to the relevant requirements of the 2020 edition of the Chinese Pharmacopoeia. Furthermore, the pharmacokinetic characteristics of the oral tablets were assessed in beagles. Finally, the anti-inflammatory effects of the CEP-β-CD oral tablets were evaluated in alveolar macrophage MH-S cells and a mouse pneumonia model. Our results suggest that the formulation of the CEP-β-CD inclusion complex into oral tablets is a promising preventive and therapeutic approach for lung injury caused by COVID-19.

Keywords: Anti-inflammatory; Cepharanthine; Inclusion complex; Oral tablet.

Fig. 1

Phase dissolution diagrams of CEP and β-CD.

Fig. 2

SEM images of (A) CEP, (B) β-CD, (C) Physical mixture of CEP and β-CD, (D) CEP–β-CD inclusion complex (mass ratio 1:1), (E) CEP–β-CD inclusion complex (mass ratio 2:1).

Fig. 3

XRD from different samples. (A) CEP–β-CD inclusion, (B) Physical mixture of CEP and β-CD, (C) β-CD, (D) CEP.

Fig. 4

FT-IR results. (A) Physical mixture of CEP and β-CD, (B) CEP–β-CD inclusion, (C) CEP, (D) β-CD.

Fig. 5

TG-DSC results. (A) CEP, (B) β-CD, (C) physical mixture of CEP and β-CD, (D) CEP–β-CD inclusion complex.

Fig. 6

Characteristics of CEP oral tablets. (A) Weight variation, (B) friability, (C) hardness, (D) disintegration time limit.

Fig. 7

In vitro drug solubility (A) and pharmacokinetics (B,C) of CEP oral tablets.

Fig. 8

Mechanistic evaluation in cells. (A) Cytotoxicity assessment and cell viability of MH-S cells treated with the CEP–β-CD inclusion complex. (B) CEP–-β-CD inclusion complex inhibits the LPS-induced secretion of inflammatory cytokines. n = 5, , **** P < 0.0001, *** P < 0.001 vs. the model group.

Fig. 9

Pharmacodynamics study. (A) Appearance of lung tissue and histologic features of lung sections (H&E staining, 100×). (B) IL-6, TNF-α, and IL-1β levels in mouse plasma. n = 5, : **** P < 0.0001 compared to the model group.

Fig. 10

Expression of lung inflammatory cell markers. (A) Immunohistochemical staining (20×) of the lung hematopoietic cell marker CD45, the macrophage marker CD68, and the neutrophil marker Ly6G. (B) Average optical density of CD45+, CD68+, and Ly6G + cells in the lungs. n = 5, ; * P < 0.05 vs. the model group.