Complexation-based spectrofluorimetric method for besifloxacin determination: Combined experimental and computational insights.

Mohamed, AA; Maklad, RM; Zeid, AM; Mostafa, IM

Complexation-based spectrofluorimetric method for besifloxacin determination: Combined experimental and computational insights.

Mohamed, AA Maklad, RM Zeid, AM Mostafa, IM

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Publisher:: ELSEVIER
Publication Type:: Journal Article
Citation:: Anal Chim Acta, 2025, 1372, pp. 344446
Issue Date:: 2025-10-22

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Field	Value	Language
dc.contributor.author	Mohamed, AA
dc.contributor.author	Maklad, RM
dc.contributor.author	Zeid, AM
dc.contributor.author	Mostafa, IM
dc.date.accessioned	2026-02-16T02:45:45Z
dc.date.available	2025-07-17
dc.date.available	2026-02-16T02:45:45Z
dc.date.issued	2025-10-22
dc.identifier.citation	Anal Chim Acta, 2025, 1372, pp. 344446
dc.identifier.issn	0003-2670
dc.identifier.issn	1873-4324
dc.identifier.uri	http://hdl.handle.net/10453/193521
dc.description.abstract	Fluorescence-based analytical methods offer high sensitivity, cost-effectiveness, and simplicity for pharmaceutical analysis. Besifloxacin hydrochloride (Bfln.HCl), a fluoroquinolone antibiotic used to treat eye infections, exhibits native fluorescence that can be enhanced in acidic media. However, the mechanism of this enhancement has not been fully explored. To address this, we developed a novel spectrofluorimetric method that enhances Bfln.HCl fluorescence using acetate buffer of pH 4.0. A 10 nm redshift in the excitation wavelength and a significant increase in fluorescence intensity at 440 nm were observed upon the addition of acetate buffer. Density Functional Theory (DFT) calculations revealed that the fluorescence enhancement results from the formation of 1:2 cyclic complexes between Bfln+ and acetic acid (AcOH). Thermodynamic analysis indicated that the Bfln+/[2AcOH] complex was the most stable, exhibiting the lowest HOMO-LUMO energy gap, consistent with the observed fluorescence enhancement. The method demonstrated high sensitivity (LOD = 22.6 ng mL-1), selectivity, and a linear range of 100-1000 ng mL-1, and it was successfully applied to ophthalmic preparations and artificial aqueous humor samples, yielding high recoveries. This method provides a cost-effective, sensitive alternative to chromatographic and electrochemical methods for Bfln.HCl determination, eliminating the need for complex derivatization, expensive reagents, or nanomaterials fabrications. Green analytical chemistry assessments (AGREE, BAGI, and RGB models) confirmed the method's environmental sustainability. This study offers both experimental and computational insights into the fluorescence enhancement mechanism of Bfln.HCl, laying the groundwork for extending this approach to other fluoroquinolone antibiotics.
dc.format	Print-Electronic
dc.language	eng
dc.publisher	ELSEVIER
dc.relation.ispartof	Anal Chim Acta
dc.relation.isbasedon	10.1016/j.aca.2025.344446
dc.rights	info:eu-repo/semantics/openAccess
dc.subject	0301 Analytical Chemistry, 0399 Other Chemical Sciences
dc.subject.classification	Analytical Chemistry
dc.subject.classification	3401 Analytical chemistry
dc.subject.classification	4004 Chemical engineering
dc.subject.classification	4018 Nanotechnology
dc.subject.mesh	Fluoroquinolones
dc.subject.mesh	Spectrometry, Fluorescence
dc.subject.mesh	Azepines
dc.subject.mesh	Density Functional Theory
dc.subject.mesh	Anti-Bacterial Agents
dc.subject.mesh	Thermodynamics
dc.subject.mesh	Azepines
dc.subject.mesh	Fluoroquinolones
dc.subject.mesh	Anti-Bacterial Agents
dc.subject.mesh	Spectrometry, Fluorescence
dc.subject.mesh	Thermodynamics
dc.subject.mesh	Density Functional Theory
dc.subject.mesh	Fluoroquinolones
dc.subject.mesh	Spectrometry, Fluorescence
dc.subject.mesh	Azepines
dc.subject.mesh	Density Functional Theory
dc.subject.mesh	Anti-Bacterial Agents
dc.subject.mesh	Thermodynamics
dc.title	Complexation-based spectrofluorimetric method for besifloxacin determination: Combined experimental and computational insights.
dc.type	Journal Article
utslib.citation.volume	1372
utslib.location.activity	Netherlands
utslib.for	0301 Analytical Chemistry
utslib.for	0399 Other Chemical Sciences
pubs.organisational-group	University of Technology Sydney
pubs.organisational-group	University of Technology Sydney/Faculty of Science
pubs.organisational-group	University of Technology Sydney/Faculty of Science/School of Mathematical and Physical Sciences
utslib.copyright.status	open_access	*
dc.rights.license	This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0). To view a copy of this license, visit https://creativecommons.org/licenses/by/4.0/
dc.date.updated	2026-02-16T02:45:43Z
pubs.publication-status	Published
pubs.volume	1372

Abstract:

Fluorescence-based analytical methods offer high sensitivity, cost-effectiveness, and simplicity for pharmaceutical analysis. Besifloxacin hydrochloride (Bfln.HCl), a fluoroquinolone antibiotic used to treat eye infections, exhibits native fluorescence that can be enhanced in acidic media. However, the mechanism of this enhancement has not been fully explored. To address this, we developed a novel spectrofluorimetric method that enhances Bfln.HCl fluorescence using acetate buffer of pH 4.0. A 10 nm redshift in the excitation wavelength and a significant increase in fluorescence intensity at 440 nm were observed upon the addition of acetate buffer. Density Functional Theory (DFT) calculations revealed that the fluorescence enhancement results from the formation of 1:2 cyclic complexes between Bfln+ and acetic acid (AcOH). Thermodynamic analysis indicated that the Bfln+/[2AcOH] complex was the most stable, exhibiting the lowest HOMO-LUMO energy gap, consistent with the observed fluorescence enhancement. The method demonstrated high sensitivity (LOD = 22.6 ng mL-1), selectivity, and a linear range of 100-1000 ng mL-1, and it was successfully applied to ophthalmic preparations and artificial aqueous humor samples, yielding high recoveries. This method provides a cost-effective, sensitive alternative to chromatographic and electrochemical methods for Bfln.HCl determination, eliminating the need for complex derivatization, expensive reagents, or nanomaterials fabrications. Green analytical chemistry assessments (AGREE, BAGI, and RGB models) confirmed the method's environmental sustainability. This study offers both experimental and computational insights into the fluorescence enhancement mechanism of Bfln.HCl, laying the groundwork for extending this approach to other fluoroquinolone antibiotics.

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http://hdl.handle.net/10453/193521