Charge-transfer chemistry of azithromycin, the antibiotic used worldwide to treat the coronavirus disease (COVID-19). Part I: Complexation with iodine in different solvents

Abstract

Around the world, the antibiotic azithromycin (AZM) is currently being used to treat the coronavirus disease (COVID-19) in conjunction with hydroxychloroquine or chloroquine. Investigating the chemical and physical properties of compounds used alone or in combination to combat the COVID-19 pandemic is of vital and pressing importance. The purpose of this study was to characterize the charge transfer (CT) complexation of AZM with iodine in four different solvents: CH 2 Cl 2 , CHCl 3 , CCl 4 , and C 6 H 5 Cl. AZM reacted with iodine at a 1:1 M ratio (AZM to I 2 ) in the CHCl 3 solvent and a 1:2 M ratio in the other three solvents, as evidenced by data obtained from an elemental analysis of the solid CT products and spectrophotometric titration and Job's continuous variation method for the soluble CT products. Data obtained from UV–visible and Raman spectroscopies indicated that AZM strongly interacted with iodine in the CH 2 Cl 2 , CCl 4 , and C 6 H 5 Cl solvents by a physically potent n→σ* interaction to produce a tri-iodide complex formulated as [AZM·I + ]I 3 − . XRD and TEM analyses revealed that, in all solvents, the AZM-I 2 complex possessed an amorphous structure composed of spherical particles ranging from 80 to 110 nm that tended to aggregate into clusters. The findings described in the present study will hopefully contribute to optimizing the treatment protocols for COVID-19.

Charge-transfer complexation of TCNE with azithromycin, the antibiotic used worldwide to treat the coronavirus disease (COVID-19). Part IV: A comparison between solid and liquid interactions

“…We believe providing new insight into the CT chemistry of AZM will help researchers and physicians alike to improve the treatment protocols for COVID-19. As a continuation of our previous works [67] , [68] , [69] that aim to furnish a big-picture perspective on the CT chemistry of azithromycin by examining its complexation with several acceptors (σ- and π-) and the resultant CTCs, in this work, we examine the CT interaction between AZM (donor) and tetracyanoethylene (TCNE; acceptor) in both the solid-solid and liquid-liquid states. The solid-solid interaction generated a solid CT complex by grinding solid AZM and TCNE powders together without adding any solvents, while the liquid-liquid interaction also resulted in a solid CT complex but by mixing acetonitrile solutions of AZM and TCNE and filtering off the formed precipitate.…”

Increasing the Efficacy of Seproxetine as an Antidepressant Using Charge–Transfer Complexes

“…Charge–transfer (CT) complexation, or electron–donor transfer, is a crucial aspect of biochemical and biological processes such as drug design, enzyme catalysis, and ion sensing [ 9 ]. The pharmacodynamics and thermodynamics of therapeutic substances and biological processes in the human body are studied using charge–transfer complexation interactions [ 10 , 11 , 12 , 13 , 14 ]. In biological systems, charge–transfer complexes may play a crucial function.…”

Charge-transfer chemistry of two corticosteroids used adjunctively to treat COVID-19. Part I: Complexation of hydrocortisone and dexamethasone donors with DDQ acceptor in five organic solvents

“…Reactions that involve the transfer of an electronically charged particle from an electron-rich donor (D) molecule to an electron-deficient acceptor (A) molecule (D → A) are known as charge transfer (CT) complexations or donor–acceptor interactions [20] , [21] , [22] , [23] , [24] , [25] , [26] , [27] . The unique physical, biological, chemical properties of the products resulting from CT interactions have gained the attention of researchers in both basic (physics, chemistry, biochemistry, biology) and applied (engineering, material science, industry, technology, pharmacology, medicine) sciences [28] , [29] , [30] , [31] , [32] , [33] , [34] , [35] , [36] , [37] , [38] , [39] , [40] , [41] , [42] , [43] , [44] , [45] , [46] , [47] , [48] , [49] , [50] , [51] , [52] , [53] , [54] , [55] , [56] , [57] , [58] , [59] , [60] , [61] , [62] , [63] , [64] , [65] , [66] , [67] , [68] , [69] , [70] , [71] , [72] , [73] , [74] , [75] , [76] , [77] , [78] , [79] , [80] , [21] ,…”