A new fluorescence method for specific determination of tedizolid in real human plasma: Based on twisted intramolecular charge transfer (TICT) blocking

Sustainable and Green Fluorescence Method for the Determination of Cloperastine in Human Plasma: Greenness Assessment

A newly green method for the sensitive quantification of cloperastine, a cough suppressant, in spiked human plasma and its pharmaceutical formulation was designed for the first time. The established method depends on the enhancement of the weak fluorescence of cloperastine using 50 mM sulfuric acid to impair the photoinduced electron transfer produced from the nitrogen atom of piperidine moiety in cloperastine. This full protonation in an acid medium leads to an enhancement in the fluorescence of cloperastine, permitting its linear determination from 0.2 to 5.0 µg/mL with LOD and LOQ of 0.04 and 0.13 µg/mL, respectively. Moreover, the studied drug was estimated in its pharmaceutical market formulations as well as spiked human plasma. Furthermore, the greenness of the described method was evaluated.

Fine-tuning Fluorescence of Amlodipine Adopting on Blocking of Photoinduced Electron Transfer (PET): Application in Human Plasma

Assessing medication adherence through the determination of antihypertensive drugs in biological matrices holds significant importance. Amlodipine (AP), a potent antihypertensive medication extensively prescribed for hypertensive patients, is particularly noteworthy in this context. This article aims to introduce a rapid, simple, improved sensitivity, and reproducibility in detecting AP in its pure form, tablet formulation, and spiked human plasma than the other reported methods. The proposed method utilizes a fluorescence approach, relying on the inhibition of the intramolecular photoinduced electron transfer (PET) effect of the lone pair of the N-atom in the primary amino moiety of AP. This inhibition is achieved by acidifying the surrounding medium using 0.2 M acetic acid. By blocking PET, the target AP drug is sensitively detected, at [Formula: see text] 423 nm over a concentration range 25-500 ng mL- 1 showcasing an exceptionally low quantitation limit of 1.41 ng mL- 1. Notably, this innovative technique was successfully applied to detect AP in its solid dosage form and spiked human plasma. Remarkably, matrix interference was found to be insignificant, underscoring the robustness and applicability of the established approach. The combination of speed, sensitivity, and reproducibility makes this method particularly suitable for assessing medication adherence in patients prescribed AP for hypertension.

Green and inventive fluorescence approach for levodropropizine determination in human plasma

A green, rapid and sensitive fluorimetric method to quantify levodropropizine (LVP) in human plasma was exploited for the first time. The proposed method adopts LVP's intrinsic fluorescence in distilled water at a detecting emission of 345 nm following excitation at 240 nm. LVP displayed linearity across concentrations ranging from 50 to 1000 ng mL-1, with a detection limit of 0.77 ng mL-1 and a quantification limit of 2.33 ng mL-1. Thorough validation confirmed its reliability, successfully determining LVP in tablets with an average recovery of 98.64 ± 1.07 %. Furthermore, the method's applicability extended to estimate the studied drug in spiked human plasma with excellent obtained percentage recoveries (98.68 ± 1.28-100.14 ± 1.23).

Improving fluorescence emission of cyproheptadine by hindering its intramolecular photoinduced electron transfer (PET): Application to content uniformity testing and human plasma

The ability to determine antihistaminic drugs in biological matrices is critical for the medication adherence assessment. Among these antihistaminic medications, cyproheptadine (CPD); that is acting as a potent first-generation antihistaminic drug that has been extensively prescribed for allergic patients. Most of the established approaches for CPD detection are not appropriate for this purpose owing to their weak sensitivity, lack of rapidity, and complicated experimental procedures. Herein, we present a very fast, highly sensitive, and reproducible approach for the detection of CPD in its pure form, tablet formulation, and spiked human plasma. The photoluminescence approach depends on hindering the intramolecular photoinduced electron transfer (PET) effect of the lone pair of the N-atom present on the piperidine ring of CPD by making the surrounding medium acidic using 1.0 M acetic acid. Based on blocking PET, the target CPD drug has been sensitively detected from 5.0 to 500 ng mL-1 with a very low detection and quantitation limit of 7.01 and 21.25 ng mL-1, respectively. Moreover, the established approach was used for checking the tablet content uniformity testing for each tablet and spiked human plasma, and noteworthy, the matrices interference was insignificant.

Photoluminescence detection of nadifloxacin: Adopts switching off photoinduced electron transfer (PET)

A new fluorimetric sensing method for the selective and sensitive quantification of nadifloxacin (antibacterial agent, NDF) was established for the first time. The introduced method relies on blocking the photoinduced electron transfer (PET) effect of the nitrogen atom presented on the piperidine ring in NDF by fine-tuning the pH of the surrounding medium through its protonation using 0.5 M acetic acid. This protonation turns the weak fluorescence of NDF into stronger fluorescence intensity, allowing its selective and sensitive detection in its pure state as well as cream pharmaceutical formulation without any obstruction from the common excipients. The developed method has shown an NDF detection limit of 1.72 ng mL-1 and a quantification limit of 5.20 ng mL-1.

Analytical Methodologies for the Estimation of Oxazolidinone Antibiotics as Key Members of anti-MRSA Arsenal: A Decade in Review

Gram-positive bacterial infections are among the most serious diseases related with high mortality rates and huge healthcare costs especially with the rise of antibiotic-resistant strains that limits treatment options. Thus, development of new antibiotics combating these multi-drug resistant bacteria is crucial. Oxazolidinone antibiotics are the only totally synthetic group of antibiotics that showed activity against multi-drug resistant Gram positive bacteria including MRSA because of their unique mechanism of action in targeting protein synthesis. This group include approved marketed members (tedizolid, linezolid and contezolid) or those under development (delpazlolid, radezolid and sutezolid). Due to the significant impact of this class, larger number of analytical methods were required to meet the needs of both clinical and industrial studies. Analyzing these drugs either alone or with other antimicrobial agents commonly used in ICU, in the presence of pharmaceutical or endogenous biological interferences, or in the presence of matrix impurities as metabolites and degradation products poses a big analytical challenge. This review highlights current analytical approaches published in the last decade (2012-2022) that dealt with the determination of these drugs in different matrices and discusses their advantages and disadvantages. Various techniques have been described for their determination including chromatographic, spectroscopic, capillary electrophoretic and electroanalytical methods. The review comprises six sections (one for each drug) with their related tables that depict critical figures of merit and some experimental conditions for the reviewed methods. Furthermore, future perspectives about the analytical methodologies that can be developed in the near future for determination of these drugs are suggested.

High CT-Fluorophore Featuring a Basic Moiety into D-A Chain as a pKa Probe

The determination of acidity represents a significant challenge within fluorometry, and no effective strategy has been developed successfully yet. It is attributed to the fact that acidity tends to be enhanced upon excitation, giving, in general, an overestimation of the ionization constant, pK_a. Herein, we developed a strategy for pK_a estimation of Brønsted acids in solution through fluorometry by using a convenient pK_a probe, N¹-aryl-7-methoxy-2-(trifluoromethyl)benzo[b][1,8]naphthyridin-4(1H)-one. It allowed us to obtain a linear log K_SV versus pK_a correlation derived from the selective quenching response of the probe by an interaction with different Brønsted acids. The key points of N¹-aryl-7-methoxy-2-(trifluoromethyl)benzo[b][1,8]naphthyridin-4(1H)-one as a pK_a probe were (i) the location of a weak basic moiety in the donor-acceptor chain of the fluorophore, which favors a selective quenching of the intramolecular charge-transfer process according to the acidity of acid, and (ii) the high CT character upon excitation that promotes higher quenching magnitudes and favors a wider pK_a range (19.5pK_a) for the log K_SV versus pK_a correlation. Other key principles were to delimit the study to pure proton transfer and nonfluorescent acids, which allowed restricting the quenching response to a process dependent mainly on the acid-base equilibrium. All these findings open a new perspective as a proof of concept to design effective fluorescent pK_a probes.