Hypericin emulsomes combined with hollow microneedles as a non-invasive photodynamic platform for rheumatoid arthritis treatment

Rheumatoid arthritis (RA) is a joint-destructive autoimmune disease that severely affects joint function. Despite the variability of treatment protocols, all of them are associated with severe side effects that compromise patient compliance. The main aim of the current study is to prepare localized effective RA treatment with reduced side effects by combining nanoencapsulation, photodynamic therapy (PDT) and hollow microneedles (Ho-MNs) to maximize the pharmacological effects of hypericin (HYP).

To attain this, HYP-loaded emulsomes (EMLs) were prepared, characterized and administered through intradermal injection using AdminPen™ Ho-MNs combined with PDT in rats with an adjuvant-induced RA model. The prepared EMLs had a spherical shape and particle size was about 93.46 nm with an absolute entrapment efficiency. Moreover, confocal imaging indicated the interesting capability of Ho-MNs to deposit the HYP EMLs to a depth reaching 1560 µm into the subcutaneous tissue. In vivo, study results demonstrated that the group treated with HYP EMLs through Ho-MNs combined with PDT had no significant differences in joint diameter, TNF-α, IL1, HO-1, NRF2 and SD levels compared with the negative control group.

Similarly, rats treated with the combination of HYP EMLs, Ho-MNs and PDT showed superior joint healing efficacy compared with the groups treated with HYP EMLs in dark, HYP ointment or HYP in microneedles in histopathological examination. These findings highlight the promising potential of photoactivated HYP EMLs when combined with Ho-MNs technology for RA management. The presented therapeutic EMLs-MNs platform could serve as a powerful game-changer in the development of future localized RA treatments.

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Compritol (Glyceryl dibehenate) and Lipoid S 100 (Phosphatidylcholine, content ≥94.0 %) were provided by Gattefosśe (Saint-Priest, France) and Lipoid AG (Ludwigshafen, Germany), respectively. Cholesterol and complete Freund’s adjuvant (CFA) was purchased from Sigma-Aldrich (Steinem, Germany). Hypericin (Isolated from H. perforatum, purity >99 % HPLC) was obtained from Planta Natural Products GmbH, Erlgasse 48, Austria.

Heba Abd-El-Azim, Haidy Abbas, Nesrine El Sayed, Mohamed R. Mousa, Hadil M. Elbardisy, Mariam Zewail,
Hypericin emulsomes combined with hollow microneedles as a non-invasive photodynamic platform for rheumatoid arthritis treatment, International Journal of Pharmaceutics, Volume 653, 2024, 123876, ISSN 0378-5173, https://doi.org/10.1016/j.ijpharm.2024.123876.

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