Synthesis, spectroscopic, and biological evaluation of some levofloxacin metal complexes

Imipenem-metal complexes: Computational analysis and toxicity studies with wastewater model microorganisms

The occurrence of antibiotic residues in diverse water sources has long been acknowledged as a potential health concern due to the emergence and spread of antibiotic-resistant bacteria and genes. However, there have been limited studies into the presence of antibiotic-metal complexes (AMCs) in real-time wastewater matrices, and their impact on wastewater microbial communities. The present work, in this regard, investigated the stability of Imipenem-metal complexes (Me = Mg (II), Ca (II), Fe (II), Cu (II), and Al (III)) with computational studies, stoichiometry with potentiometric measurements, and their antibacterial activity towards wastewater model microorganisms- Bacillus subtilis (B. subtilis) and Escherichia coli (E. Coli) by Colony Forming Unit (CFU) method. The lower energy of Imipenem-metal complexes than the parent antibiotic- Imipenem, during energy optimization using density functional (DFT) methods, revealed that metal interactions of Imipenem stabilize the drug by minimizing its energy. Further, CFU studies indicated that these complexes display higher antimicrobial activity than parent antibiotics. The electron delocalization over the entire chelated system (AMCs) reduces polarity and increases the lipophilicity of the complexes, thereby facilitating stronger interaction between AMCs and the bacterial cell membrane. Results indicate increased antibacterial activity of Imipenem-metal complexes for both E. coli and B. subtilis. The antibacterial activity, was however, more pronounced in B. subtilis, with >97% growth inhibition for metal complexes of Imipenem (at a Minimum Inhibitory Concentration of 20 nM or 6 ppb (i.e., MIC90)), for both the stoichiometric ratios (metal to ligand) ratios (M: L 1: 1 and 2: 1). All around, with increased stability and toxicity, AMCs are emerging as contaminants of concern and demand immediate attention to devise methods for their removal.

A perception into binary and ternary copper (II) complexes: synthesis, characterization, DFT modeling, antimicrobial activity, protein binding screen, and amino acid interaction

Ensuring healthy lives and promoting well-being for all at all ages is the third goal of the sustainable development plan, so it was necessary to identify the most important problems that threaten health in our world. The World Health Organization declared that antibiotic resistance is one of the uppermost global public health threats facing humanity and searching for new antibiotics is slow. This problem can be approached by improving available drugs to combat various bacterial threats. To circumvent bacterial resistance, three copper(II) complexes based on the pefloxacin drug were prepared and characterized using analytical, spectroscopic, and thermal techniques. The resulting data suggested the formation of one octahedral binary and two distorted square pyramidal ternary complexes. Fluorescence spectra results revealed the formation of a turn-on fluorophore for amino acid detection. Computational calculations investigated quantum and reactivity parameters. Molecular electrostatic potential profiles and noncovalent bond interaction-reduced density gradient analysis indicated the active sites on the complex surface. The complexes were subjected to six microbial species, where the octahedral binary complex provoked its antimicrobial potency in comparison with ternary complexes. The enhanced antimicrobial activity against gram-negative bacterium E-coli compared to gentamicin was exhibited by the three complexes. Docking simulation was performed based on the crystal structure of E. coli and S. pneumoniae receptors using 5I2D and 6O15 codes. The binary complex exhibited a potent fitness score with 5I2D (TBE = - 107 kcal/mol) while ternary complexes displayed the highest docked score of fitness with 6O15.

The Benefits and Challenges of Antibiotics-Non-Steroidal Anti-Inflammatory Drugs Non-Covalent Reaction

Recently, non-covalent reactions have emerged as approaches to improve the physicochemical properties of active pharmaceutical ingredients (API), including antibiotics and non-steroidal anti-inflammatory drugs (NSAIDs). This review aimed to present and discuss the non-covalent reaction products of antibiotics, including salt and neutral multi-component solid forms, by framing their substituents and molar ratios, manufacturing techniques, characterization methods, benefits, potency changes, and toxicity, and is completed with an analysis of the development of computational models used in this field. Based on the data, NSAIDs are the most-developed drugs in multi-component system preparations, followed by antibiotics, i.e., antituberculosis and fluoroquinolones. They have reacted with inorganic elements, excipients, nutraceuticals, natural products, and other drugs. However, in terms of treatments for common infections, fluoroquinolones are more frequently used. Generally, NSAIDs are acquired on an over-the-counter basis, causing inappropriate medication. In addition, the pKa differences between the two groups of medicine offer the potential for them to react non-covalently. Hence, this review highlights fluoroquinolone-NSAID multi-component solid systems, which offer some benefits. These systems can increase patient compliance and promote the appropriate monitoring of drug usage; the dual drug multi-component solids have been proven to improve the physicochemical properties of one or both components, especially in terms of solubility and stability. In addition, some reports show an enhancement of the antibiotic activity of the products. However, it is important to consider the possibility of activity changes, interaction, and toxicity when using drug combinations. Hence, these aspects also are discussed in this review. Finally, we present computational modeling, which has been utilized broadly to support multi-component system designs, including coformer screening, preparation methods, and structural modeling, as well as to predict physicochemical properties, potency, and toxicity. This integrated review is expected to be useful for further antibiotic-NSAID multi-component system development.

Stability and Antibiotic Potency Improvement of Levofloxacin by Producing New Salts with 2,6- and 3,5-Dihydroxybenzoic Acid and Their Comprehensive Structural Study

Recently, solid-state engineering has become a promising approach to improving the stability and potency of antibiotics. Levofloxacin (LF) is a broad-spectrum fluoroquinolone antibiotic marketed in solid and solution dosage forms. However, this substance forms solid hydrates under ambient conditions and degrades due to lighting, which may change its solid properties and dose. In addition, resistance cases have been reported due to long-time antibiotic usage. This research aims to allow LF to react with antioxidant dihydroxybenzoic acid (DHBA), which has low antimicrobial activity, to produce a more stable compound under water and lighting conditions and improve LF's potency. The experiment begins with a screening to select potential DHBA isomers that can react with LF and predict the stoichiometric ratio using phase diagrams, which show that 2,6-DHBA and 3,5-DHBA are prospective antioxidants that can react with LF in a (1:1) molar ratio. Multicomponent systems are prepared by dissolving the LF-DHBA mixture in (1:1) ethanol-methanol (95% grade) and evaporating it. Then, the new solid phase formation is confirmed by thermal analysis and powder X-ray diffractometry. Next, infrared spectrophotometry and neutron magnetic resonance analyses are used to identify the LF-DHBA's interactions. Finally, single-crystal X-ray diffractometry is used to solve the three-dimensional structure of the multicomponent system. We then conduct a hygroscopicity and stability test followed by a lighting and potency test using the microdilution method. Our data reveal that both reactions produce salts, which are named LF-26 and LF-35, respectively. Structurally, LF-26 is found in an anhydrous form with a triclinic crystal packing, while LF-35 is a hemihydrate in a monoclinic system. Afterward, both salts are proven more stable regarding water adsorption and UV lighting than LF. Finally, both multicomponent systems have an approximately two-fold higher antibiotic potency than LF. LF-26 and LF-35 are suitable for further development in solid and liquid dosage formulations, especially LF-35, which has superior stability compared with LF-26.

Computational analysis, Urbach energy and Judd-Ofelt parameter of warm Sm3+ complexes having applications in photovoltaic and display devices

In this work, six reddish orange Sm³⁺ complexes were synthesized using organic ligand (L) and secondary ligands having hetero atoms by a one-step significant liquid-assisted grinding method and were characterized by spectroscopic techniques. The Urbach energy and band gap energy of the complexes were inspected by a linear fit. Using a least square fitting method, the Judd-Ofelt parameter and radiative properties were also determined. Thermal analysis, colorimetric analysis, luminescence decay time and anti-microbial properties of complexes were studied. The luminescence emission spectra of binary and ternary complexes displayed three characteristic peaks at 565, 603 and 650 nm in the powder form and four peaks at 563, 605, 646 and 703 nm in a solution phase due to ⁴G_5/2 → ⁶H_5/2, ⁴G_5/2 → ⁶H_7/2, ⁴G_5/2 → ⁶H_9/2 and ⁴G_5/2 → ⁶H_11/2 transitions respectively. The most intense transition in the solid phase (⁴G_5/2 → ⁶H_7/2) is accountable for orange color, and in the solution form, the highly luminescent peak (⁴G_5/2 → ⁶H_9/2) is responsible for reddish orange color of Sm³⁺ complexes. PXRD and SEM analyses suggested that the complexes possess a nanoparticle grain size with crystalline nature. The decent optoelectrical properties of title complexes in the orangish-red visible domain indicated possible applications in the manufacturing of display and optoelectronic devices.

New Organic Salt from Levofloxacin-Citric Acid: What Is the Impact on the Stability and Antibiotic Potency?

This research dealt with the composition, structure determination, stability, and antibiotic potency of a novel organic salt composed of levofloxacin (LF) and citric acid (CA), named levofloxacin-citrate (LC). After a stoichiometric proportion screening, the antibiotic-antioxidant reaction was conducted by slow and fast evaporation methods. A series of characterizations using thermal analysis, powder X-ray diffractometry, vibrational spectroscopy, and nuclear magnetic resonance confirmed LC formation. The new organic salt showed a distinct thermogram and diffractogram. Next, Fourier transform infrared indicated the change in N-methylamine and carboxylic stretching, confirmed by ¹H nuclear magnetic resonance spectra to elucidate the 2D structure. Finally, single-crystal diffractometry determined LC as a new salt structure three-dimensionally. The attributive improvements were demonstrated on the stability toward the humidity and lighting of LC compared to LF alone. Moreover, the antibiotic potency of LF against Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative) enhanced ~1.5–2-fold by LC. Hereafter, LC is a potential salt antibiotic-antioxidant combination for dosage formulas development.

Antibiotic-metal complexes in wastewaters: fate and treatment trajectory

Unregulated usage, improper disposal, and leakage from pharmaceutical use and manufacturing sites have led to high detection levels of antibiotic residues in wastewater and surface water. The existing water treatment technologies are insufficient for removing trace antibiotics and these residual antibiotics tend to interact with co-existing metal ions and form antibiotic-metal complexes (AMCs) with altered bioactivity profile and physicochemical properties. Typically, antibiotics, including tetracyclines, fluoroquinolones, and sulphonamides, interact with heavy metals such as Fe²⁺, Co²⁺, Cu²⁺, Ni²⁺, to form AMCs which are more persistent and toxic than parent compounds. Although many studies have reported antibiotics detection, determination, distribution and risks associated with their environmental persistence, very few investigations are published on understanding the chemistry of these complexes in the wastewater and sludge matrix. This review, therefore, summarizes the structural features of both antibiotics and metals that facilitate complexation in wastewater. Further, this work critically appraises the treatment methods employed for antibiotic removal, individually and combined with metals, highlights the knowledge gaps, and delineates future perspectives for their treatment.

Synthesis and physicochemical characterizations of coordination between palladium(ii) metal ions with floroquinolone drugs as medicinal model against cancer cells: novel metallopharmaceuticals

Three new complexes of palladium(ii) floroquinolone drugs (levofloxacin (HLVX), pefloxacin mesylate (HPFX) and lomefloxacin (HLMX)) were prepared in alkaline media at pH = 9.

4-Quinolone derivatives and their activities against Gram positive pathogens

Gram-positive bacteria are responsible for a broad range of infectious diseases, and the emergency and wide spread of drug-resistant Gram-positive pathogens including MRSA and MRSE has caused great concern throughout the world. 4-Quinolones which are exemplified by fluoroquinolones are mainstays of chemotherapy against various bacterial infections including Gram-positive pathogen infections, and their value and role in the treatment of bacterial infections continues to expand. However, the resistance of Gram-positive organisms to 4-quinolones develops rapidly and spreads widely, making them more and more ineffective. To overcome the resistance and reduce the toxicity, numerous of 4-quinolone derivatives were synthesized and screened for their in vitro and in vivo activities against Gram-positive pathogens, and some of them exhibited excellent potency. This review aims to outlines the recent advances made towards the discovery of 4-quinolone-based derivatives as anti-Gram-positive pathogens agents and the critical aspects of design as well as the structure-activity relationship of these derivatives. The enriched SAR paves the way to the further rational development of 4-quinolones with a unique mechanism of action different from that of the currently used drugs to overcome the resistance, well-tolerated and low toxic profiles.

The effect of some fluoroquinolone family members on biospeciation of copper(II), nickel(II) and zinc(II) ions in human plasma

The speciation of Cu2+, Ni2+ and Zn2+ ions in the presence of the fluoroquinolones (FQs) moxifloxacin, ofloxacin, levofloxacin and ciprofloxacin, in human blood plasma was studied under physiological conditions by computer simulation. The speciation was calculated using an updated model of human blood plasma including over 6,000 species with the aid of the program Hyss2009. The identity and stability of metal-FQ complexes were determined by potentiometric (310 K, 0.15 mol/L NaCl), spectrophotometric, spectrofluorimetric, ESI-MS and 1H-NMR measurements. In the case of Cu2+ ion the concentration of main low molecular weight (LMW) plasma complex (Cu(Cis)His) is very slightly influenced by all examined FQs. FQs show much higher influence on main plasma Ni2+ and Zn2+ complexes: (Ni(His)2 and Zn(Cys)Cit, respectively. Levofloxacin exhibits the highest influence on the fraction of the main nickel complex, Ni(His)2, even at a concentration level of 3×10⁻⁵ mol/L. The same effect is seen on the main zinc complex, Zn(Cys)Cit. Calculated plasma mobilizing indexes indicate that ciprofloxacin possesses the highest mobilizing power from plasma proteins, toward copper ion, while levofloxacin is the most influential on nickel and zinc ions. The results obtained indicate that the drugs studied are safe in relation to mobilization of essential metal ions under physiological conditions. The observed effects were explained in terms of competitive equilibrium reactions between the FQs and the main LMW complexes of the metal ions.

Metal complexes of quinolone antibiotics and their applications: an update

Quinolones are synthetic broad-spectrum antibiotics with good oral absorption and excellent bioavailability. Due to the chemical functions found on their nucleus (a carboxylic acid function at the 3-position, and in most cases a basic piperazinyl ring (or another N-heterocycle) at the 7-position, and a carbonyl oxygen atom at the 4-position) quinolones bind metal ions forming complexes in which they can act as bidentate, as unidentate and as bridging ligand, respectively. In the polymeric complexes in solid state, multiple modes of coordination are simultaneously possible. In strongly acidic conditions, quinolone molecules possessing a basic side nucleus are protonated and appear as cations in the ionic complexes. Interaction with metal ions has some important consequences for the solubility, pharmacokinetics and bioavailability of quinolones, and is also involved in the mechanism of action of these bactericidal agents. Many metal complexes with equal or enhanced antimicrobial activity compared to the parent quinolones were obtained. New strategies in the design of metal complexes of quinolones have led to compounds with anticancer activity. Analytical applications of complexation with metal ions were oriented toward two main directions: determination of quinolones based on complexation with metal ions or, reversely, determination of metal ions based on complexation with quinolones.