Comparison of the Efficacy of Two Novel Antitubercular Agents in Free and Liposome-Encapsulated Formulations

• Main Authors: Nikoletta Kósa, Ádám Zolcsák, István Voszka, Gabriella Csík, Kata Horváti, Lilla Horváth, Szilvia Bősze, Levente Herenyi
• Format: Article
• Language: English
• Published: MDPI AG 2021-02-01
• Series: International Journal of Molecular Sciences
• Subjects: coumaran; 2,3-dihydrobenzofuran; pH-sensitive stealth liposome; monocomponent liposome; dynamic light scattering; absorption spectrometry
• Online Access: https://www.mdpi.com/1422-0067/22/5/2457

Tuberculosis is one of the top ten causes of death worldwide, and due to the appearance of drug-resistant strains, the development of new antituberculotic agents is a pressing challenge. Employing an in silico docking method, two coumaran (2,3-dihydrobenzofuran) derivatives—TB501 and TB515—were determined, with promising in vitro antimycobacterial activity. To enhance their effectiveness and reduce their cytotoxicity, we used liposomal drug carrier systems. Two types of small unilamellar vesicles (SUV) were prepared: multicomponent pH-sensitive stealth liposome (SUV_mixed) and monocomponent conventional liposome. The long-term stability of our vesicles was obtained by the examination of particle size distribution with dynamic light scattering. Encapsulation efficiency (EE) of the two drugs was determined from absorption spectra before and after size exclusion chromatography. Cellular uptake and cytotoxicity were determined on human MonoMac-6 cells by flow cytometry. The antitubercular effect was characterized by the enumeration of colony-forming units on <i>Mycobacterium tuberculosis</i> H₃₇Rv infected MonoMac-6 cultures. We found that SUV_mixed+ TB515 has the best long-term stability. TB515 has much higher EE in both types of SUVs. Cellular uptake for native TB501 is extremely low, but if it is encapsulated in SUV_mixed it appreciably increases; in the case of TB515, quasi total uptake is accessible. It is concluded that SUV_mixed+ TB501 seems to be the most efficacious antitubercular formulation given the presented experiments; to find the most promising antituberculotic formulation for therapy further in vivo investigations are needed.