Robust HPLC–MS/MS method for levofloxacin and ciprofloxacin determination in human prostate tissue

Portable, intelligent MIECL sensing platform for ciprofloxacin detection using a fast convolutional neural networks-assisted Tb@Lu2O3 nanoemitter

Environmental pollution caused by ciprofloxacin is a major problem of global public health. A machine learning-assisted portable smartphone-based visualized molecularly imprinted electrochemiluminescence (MIECL) sensor was developed for the highly selective and sensitive detection of ciprofloxacin (CFX) in food. To boost the efficiency of electrochemiluminescence (ECL), oxygen vacancies (OVs) enrichment was introduced into the flower-like Tb@Lu2O3 nanoemitter. With the specific recognition reaction between MIP as capture probes and CFX as detection target, the ECL signal significantly decreased. According to, CFX analysis was determined by traditional ECL analyzer detector in the concentration range from 5 × 10-4 to 5 × 102 μmol L-1 with the detection limit (LOD) of 0.095 nmol L-1 (S/N = 3). Analysis of luminescence images using fast electrochemiluminescence judgment network (FEJ-Net) models, achieving portable and intelligent quick analysis of CFX. The proposed MIECL sensor was used for CFX analysis in real meat samples and satisfactory results, as well as efficient selectivity and good stability.

Ratiometric Fluorescence Detection of Levofloxacin Based on a Cube-like Zn(II)-Eu(III) Nanocluster: Functionalized Sodium Alginate Film for the Detection in Serum and Medicine

A cube-like Zn(II)-Eu(III) nanocluster 1 (molecular sizes: 1.8 × 2.0 × 2.0 nm) was constructed by the use of a new long-chain Schiff base ligand. It shows a ratiometric fluorescence response to levofloxacin (LFX) with high sensitivity and selectivity, which can be expressed as I615 nm/I550 nm = A*[LFX]2 + B*[LFX] + C. It is used to quantitatively detect the LFX concentrations in fetal calf serum (FCS) and tablets sold in pharmacy. Filter paper strips bearing 1 can be used to qualitatively detect LFX by a color change to red under a UV lamp. 1 and its hybrid with sodium alginate (SA), 1@SA, display potential applications in the qualitative detection of LFX in FCS and the medicine. The limit of detection of 1 to LFX is as low as 2.1 × 10-2 nM.

Harnessing Graphene-Modified Electrode Sensitivity for Enhanced Ciprofloxacin Detection

Increased evidence has documented a direct association between Ciprofloxacin (CFX) intake and significant disruption to the normal functions of connective tissues, leading to severe health conditions (such as tendonitis, tendon rupture and retinal detachment). Additionally, CFX is recognized as a potential emerging pollutant, as it seems to impact both animal and human food chains, resulting in severe health implications. Consequently, there is a compelling need for the precise, swift and selective detection of this fluoroquinolone-class antibiotic. Herein, we present a novel graphene-based electrochemical sensor designed for Ciprofloxacin (CFX) detection and discuss its practical utility. The graphene material was synthesized using a relatively straightforward and cost-effective approach involving the electrochemical exfoliation of graphite, through a pulsing current, in 0.05 M sodium sulphate (Na2SO4), 0.05 M boric acid (H3BO3) and 0.05 M sodium chloride (NaCl) solution. The resulting material underwent systematic characterization using scanning electron microscopy/energy dispersive X-ray analysis, X-ray powder diffraction and Raman spectroscopy. Subsequently, it was employed in the fabrication of modified glassy carbon surfaces (EGr/GC). Linear Sweep Voltammetry studies revealed that CFX experiences an irreversible oxidation process on the sensor surface at approximately 1.05 V. Under optimal conditions, the limit of quantification was found to be 0.33 × 10-8 M, with a corresponding limit of detection of 0.1 × 10-8 M. Additionally, the developed sensor's practical suitability was assessed using commercially available pharmaceutical products.

Modification of gradient HPLC method for determination of small molecules' affinity to human serum albumin under column safety conditions: Robustness and chemometrics study

In the early stages of drug discovery, beyond the biological activity screening, determining the physicochemical properties that affect the distribution of molecules in the human body is an essential step. Plasma protein binding (PPB) is one of the most important investigated endpoints. Nevertheless, the methodology for measuring %PPB is significantly less popular and standardized than other physicochemical properties, like lipophilicity. Here, we proposed how to modify protocols presented by Valko into column safety conditions and evaluated their robustness using fractional factorial design. For robustness testing, four factors were selected: column temperature, mobile phase flow rate, maximum isopropanol concentration in the mobile phase, and buffer pH. Elaborate methods have been applied for the analysis of HSA affinity for three groups of antibiotic-oriented substances that vary in chemical structure: fluoroquinolones, sulfonamides, and tetrazole derivatives. Furthermore, based on the reversed-phase chromatography the workflow of pilot studies was proposed to select molecules that have high affinity to HSA and can not be eluted from the HSA column using the concentration of organic modifier recommended by the column manufacturer.

Electrochemical Sensor Based on the Hierarchical Carbon Nanocomposite for Highly Sensitive Ciprofloxacin Determination

A new voltammetry method for the highly sensitive antibacterial drug ciprofloxacin (CIP) is presented using glassy carbon electrodes modified with hierarchical electrospun carbon nanofibers with NiCo nanoparticles (eCNF/CNT/NiCo-GCE). The use of a modified glassy carbon electrode in the form of hierarchical electrospun carbon nanofibers with NiCo nanoparticles (eCNF/CNT/NiCo) led to an LOD value as low as 6.0 µmol L-1 with a measurement sensitivity of 3.33 µA µmol L-1. The described procedure was successfully applied for CIP determination in samples with complex matrices, such as urine or plasma, and also in pharmaceutical products and antibiotic discs with satisfactory recovery values ranging between 94-104%. The proposed electrode was characterised by great stability, with the possibility of use for about 4 weeks without any significant change in the CIP peak current. The repeatability of the CIP response on the eCNF/CNT/NiCo/GC is also very good; its value measured and expressed as RSD is equal to 2.4% for a CIP concentration of 0.025 µmol L-1 (for 7 consecutive CIP voltammogram registrations). The procedure for electrode preparation is quick and simple and does not involve the use of expensive apparatus.

Controlled Drug Delivery Device for Cornea Treatment and Novel Method for Its Testing

A new solution for local anesthetic and antibiotic delivery after eye surgery is presented. A contact lens-shaped collagen drug carrier was created and loaded by Levofloxacin and Tetracaine with a riboflavin crosslinked surface layer, thus impeding diffusion. The crosslinking was confirmed by Raman spectroscopy, whereas the drug release was investigated using UV-Vis spectrometry. Due to the surface barrier, the drug gradually releases into the corneal tissue. To test the function of the carrier, a 3D printed device and a new test method for a controlled drug release, which mimics the geometry and physiological lacrimation rate of the human eye, were developed. The experimental setup with simple geometry revealed that the prepared drug delivery device can provide the prolonged release profile of the pseudo-first-order for up to 72 h. The efficiency of the drug delivery was further demonstrated using a dead porcine cornea as a drug recipient, without the need to use live animals for testing. Our drug delivery system significantly surpasses the efficiency of antibiotic and anesthetic eyedrops that would have to be applied approximately 30 times per hour to achieve the same dose as that delivered continuously by our device.

Green Automated Solid Phase Extraction to Measure Levofloxacin in Human Serum via Liquid Chromatography with Fluorescence Detection for Pharmacokinetic Study

A simple, selective, rapid, sensitive and less costly green automated solid phase extraction bio-analytical high-performance liquid chromatographic-based technique with fluorescence detection (Aut-SPE-BA-HPLC-FL) for the quantification of levofloxacin in human serum samples has been developed and validated. The serum samples were loaded into the chromatographic system without prior treatment and then injected into short (20 mm × 4.6 mm, 20 µm) protein-coated (PC) µBondapak CN (µBCN) silica pre-column (PC-µBCN-pre-column). Levofloxacin was retained and pre-concentrated on the head of the PC-µBCN-pre-column, while proteins and other polar components were eliminated using phosphate buffer saline (PBS), pH 7.4, as the first mobile phase in the extraction step. Levofloxacin is then transferred to the analytical column; ZORBAX Eclipse XDB-C18 (150 mm × 46 mm, 5 µm), through the aid of a column-switching valve technique, on-throughs the elution mode using the second mobile phase containing a methanol and phosphate buffer (0.05 M, pH 5) in a ratio of 70:30 (v/v). Levofloxacin signals were detected using a fluorescence detector operated at excitation/emission wavelengths of 295/500 nm. The proposed Aut-SPE-BA-HPLC-FL methodology showed linearity over a levofloxacin concentration range of 10–10,000 ng/mL (r2 = 0.9992), with good recoveries ranging from 87.12 to 97.55%. Because of the validation qualities in terms of linearity, recovery, precision, accuracy, selectivity and robustness, the Aut-SPE-BA-HPLC-FL method has been used in some clinical trials for therapeutic drug monitoring and the pharmacokinetic study of levofloxacin in human serum.

Determination of levofloxacin by HPLC with fluorescence detection in human breast milk

Aim: A new HPLC method with fluorescence detection has been developed and validated for the determination of levofloxacin, one of the fluoroquinolone class antibiotics, in breast milk. Materials & methods: Chromatographic separation was carried out on a reversed phase C18 column with acetonitrile and 10 mM o-phosphoric acid (25:75, v/v) mobile phase composition. Moxifloxacin was used as internal standard and the peaks were detected by fluorescence detection. Results & conclusion: Calibration graph was found linearly within the range of 2.5-500 ng/ml. Limit of detection and limit of quantification were found to be 0.63 and 2.11 ng/ml, respectively. Mean absolute recovery was 96.18%. The developed method has been successfully applied to the determination of levofloxacin in human breast milk taken from two healthy volunteers.

An electrochemical sensor for voltammetric detection of ciprofloxacin using a glassy carbon electrode modified with activated carbon, gold nanoparticles and supramolecular solvent

A highly sensitive and novel electrochemical sensor for ciprofloxacin (CIP) has been developed using gold nanoparticles deposited with waste coffee ground activated carbon on glassy carbon electrode (AuNPs/AC/GCE) and combined with supramolecular solvent (SUPRAS). The fabricated AuNPs/AC/GCE displayed good electrocatalytic activity for AuNPs. The addition of SUPRAS, prepared from cationic surfactants namely didodecyldimethylammonium bromide (DDAB) and dodecyltrimethylammonium bromide (DTAB), increased the electrochemical response of AuNPs. The detection of CIP was based on the decrease of the cathodic current of AuNPs. The electrochemical behavior of the modified electrode was investigated using cyclic voltammetry, differential pulse voltammetry and electrochemical impedance spectroscopy. Under optimum conditions, the calibration plot of CIP exhibited a linear response in the range 0.5-25 nM with a detection limit of 0.20 nM. The fabricated electrochemical sensor was successfully applied to determine CIP in milk samples with achieved recoveries of 78.6-110.2% and relative standard deviations of <8.4%. The developed method was also applied to the analysis of pharmaceutical formulation and the results were compared with high-performance liquid chromatography.Graphical abstract.

Polyvinyl Chloride Modified Carbon Paste Electrodes for Sensitive Determination of Levofloxacin Drug in Serum, Urine, and Pharmaceutical Formulations

Levofloxacin (LF) is a medically important antibiotic drug that is used to treat a variety of bacterial infections. In this study, three highly sensitive and selective carbon paste electrodes (CPEs) were fabricated for potentiometric determination of the LF drug: (i) CPEs filled with carbon paste (referred to as CPE); (ii) CPE coated (drop-casted) with ion-selective PVC membrane (referred to as C-CPE); (iii) CPE filled with carbon paste modified with a plasticizer (PVC/cyclohexanone) (referenced as P-CPE). The CPE was formulated from graphite (Gr, 44.0%) and reduced graphene oxide (rGO, 3.0%) as the carbon source, tricresyl phosphate (TCP, 47.0%) as the plasticizer; sodium tetrakis[3,5-bis(trifluoromethyl)phenyl] borate (St-TFPMB, 1.0%) as the ion exchanger; and levofloxacinium-tetraphenylborate (LF-TPB, 5.0%) as the lipophilic ion pair. It showed a sub-Nernstian slope of 49.3 mV decade⁻¹ within the LF concentration range 1.0 × 10⁻² M to 1.0 × 10⁻⁵ M, with a detection limit of 1.0 × 10⁻⁵ M. The PVC coated electrode (C-CPE) showed improved sensitivity (in terms of slope, equal to 50.2 mV decade⁻¹) compared to CPEs. After the incorporation of PVC paste on the modified CPE (P-CPE), the sensitivity increased at 53.5 mV decade⁻¹, indicating such improvement. The selectivity coefficient (log KLF2+,Fe+3pot.) against different interfering species (Na⁺, K⁺, NH⁴⁺, Ca²⁺, Al³⁺, Fe³⁺, Glycine, Glucose, Maltose, Lactose) were significantly improved by one to three orders of magnitudes in the case of C-CPE and P-CPE, compared to CPEs. The modification with the PVC membrane coating significantly improved the response time and solubility of the LF-TPB within the electrode matrix and increased the lifetime. The constructed sensors were successfully applied for LF determination in pharmaceutical preparation (Levoxin^® 500 mg), spiked urine, and serum samples with high accuracy and precision.

Batch injection analysis with amperometric detection for fluoroquinolone determination in urine, pharmaceutical formulations, and milk samples using a reduced graphene oxide-modified glassy carbon electrode

In this work, the batch injection analysis system with amperometric detection using reduced graphene oxide as a modifier of glassy carbon electrode (GCE) was investigated for the simple, fast, and sensitive monitoring of levofloxacin (LEVO) and ciprofloxacin (CIPRO) in samples of pharmaceutical formulations, synthetic urine, and milk (low- and high-fat content). LEVO and CIPRO were quantified in seven samples using amperometric measurements at +1.10 V vs Ag/AgCl, KCl(sat). The developed methods showed excellent analytical performance with limits of detection of 0.30 and 0.16 μmol L^-1, linear range from 3.0 to 50 μmol L^-1 and 1.0 to 50 μmol L^-1, relative standard deviation below 9.7 and 3.1%, and recovery ranges ranging from 80 to 107% and from 78 to 109% for LEVO and CIPRO, respectively. In addition, the minimum sample preparation (simple dilution) combined with a high analytical frequency (130 to 180 analyses per hour) can be highlighted. Thus, the methods are promising for implementation in routine analysis and quality control to different samples.

Two Cd(ii)-based metal–organic frameworks for the highly effective detection of Fe3+ ions and levofloxacin in aqueous media

Two new Cd(ii)-MOFs are hydrothermally synthesized and can be applied as dual-response sensors to identify Fe3+ and levofloxacin (LVX) with high selectivity, sensitivity and excellent reusability.

Herb-drug interaction: The effect of Polygonum capitatum extract on pharmacokinetics of levofloxacin in rats

Polygonum capitatum is a traditional medicinal plant of the Miao people and has been used to treat a variety of urological disorders in China for many years. Preparations made from water-soluble P. capitatum extracts, Relinqing® granules, are often used in combination with levofloxacin to treat urinary tract infections, and have demonstrated better clinical efficacy than either drug alone. As there is no information on the pharmacokinetics of both drugs after co-administration, a sensitive and reliable ultra-performance liquid chromatography-tandem mass spectrometry method was developed and validated to study the potential herb-drug interactions between P. capitatum and levofloxacin. This analytical method delivered high levels of specificity, recovery, accuracy, precision and preserved sample stability. When applied to study pharmacokinetic interactions after oral co-administration of P. capitatum extract (1.86 g kg^-1) and levofloxacin (42 mg kg^-1) in rats, the results indicated significant reductions in C_max and AUC_0-24h of levofloxacin, and significant increases in MRT, T_max, CLz/F and Vz/F. Moreover, pretreatment with P. capitatum extract orally did not alter the intravenous pharmacokinetics of levofloxacin. Combined and compared oral pharmacokinetic parameters, suggesting that the interacting targets might localized in the intestine during absorption. Overall, the results revealed a potential herb-drug interaction between P. capitatum and levofloxacin.

Spectrophotometric and Multivariate Calibration Techniques for Simultaneous Determination of Different Drugs in Pharmaceutical Formulations and Human Urine: Evaluation of Greenness Profile

Eco-friendly, rapid, and cost-effective two spectrophotometric methods were developed and validated for the determination of atenolol, paracetamol, hydrochlorothiazide, and levofloxacin. The first method is the newly developed extended derivative ratio (EDR) and the second method is multivariate curve resolution-alternating least squares (MCR-ALS). In the EDR method, the extended derivative ratio amplitudes at 281.6, 237.6, 279.2, and 282.8 nm were used for quantification of atenolol, paracetamol, hydrochlorothiazide, and levofloxacin, respectively. In the MCR-ALS method, calibration model was developed and correlation constraint was employed. External validation data set composed of seven mixtures was used, and different figures of merits such as root mean square error of prediction, standard error of prediction, bias, and relative error of prediction were calculated, and satisfactory results were obtained. Both methods provided comparable results. The methods were validated and applied for the determination of the target analytes in dosage forms, spiked and real human urine. Thereafter, the obtained results were statistically compared to the published methods and revealed no significant difference regarding accuracy and precision. Furthermore, the greenness profile of the methods was evaluated using the National Environmental Methods Index "NEMI" and Analytical Eco-Scale. The developed methods can be used as a valid eco-friendly and simple cost-effective alternative to the commonly used chromatographic methods for the routine analysis of the studied drugs in dosage forms and human urine.

Comparison of high-performance liquid chromatography and ultraviolet-visible spectrophotometry to determine the best method to assess Levofloxacin released from mesoporous silica microspheres/nano-hydroxyapatite composite scaffolds

An assessment of Levofloxacin by high-performance liquid chromatography (HPLC) or ultraviolet-visible spectrophotometry (UV-Vis) and its pharmacokinetics in serum or plasma was made in a previous study by the present authors. Levofloxacin-loaded mesoporous silica microspheres/nano-hydroxyapatite (n-HA) composite scaffolds comprise a novel synthetic composite scaffold that may be utilized as a drug-delivery system for clinical usage. However, few studies have been published concerning a comparison of HPLC with UV-Vis, which is the preferred method for determination of Levofloxacin. In the present study, an HPLC method was first established, and subsequently a comparison of HPLC with the UV-Vis method was performed. The standard curve was established, and recovery rate from simulated body fluid was calculated. The linear concentration range for Levofloxacin was 0.05–300 µg/ml. The regression equation for HPLC was y=0.033x+0.010, with R²=0.9991, whereas that for UV-Vis was y=0.065x+0.017, with R²=0.9999. The recovery rates of low, medium and high (5, 25 and 50 µg/ml) concentrations of Levofloxacin determined by HPLC were 96.37±0.50, 110.96±0.23 and 104.79±0.06%, respectively, whereas those for low, medium and high concentrations according to UV-Vis were 96.00±2.00, 99.50±0.00 and 98.67±0.06%, respectively. Taken together, these findings demonstrated that it is not accurate to measure the concentration of drugs loaded on the biodegradable composite composites by UV-Vis. HPLC is the preferred method to evaluate sustained release characteristics of Levofloxacin released from mesoporous silica microspheres/n-HA composite scaffolds. The present study also provides guidance on which methods should be selected for investigating the sustained release properties of drugs in tissue engineering. The accurate determination of drug concentration in the drug delivery system provides guidance for the treatment of infectious diseases.

Microextraction by Packed Molecularly Imprinted Polymer Combined Ultra-High-Performance Liquid Chromatography for the Determination of Levofloxacin in Human Plasma

Fluoroquinolones are considered as gold standard for the prevention of bacterial infections. To improve assessment of antibacterial efficacy, a novel method for determination of levofloxacin was developed and validated. Deep eutectic solvents (DESs) as only green solvent were used as a porogen for preparation of water-compatible molecularly imprinted polymers (MIPs) with a pseudotemplate. The DESs-MIPs were characterized in detail, including scanning electron microscope, nitrogen sorption porosimetry, and Fourier transform-infrared spectra. Clearly, the maximum binding capacity of levofloxacin on DESs-MIPs in water and methanol was 0.216 and 0.077 μmol g−1, respectively. The DESs-MIPs as adsorbing materials were applied in microextraction by packed sorbent (MEPS), and the DESs-MIPs-MEPS conditions were optimized. The DESs-MIPs-MEPS coupled with ultra-high-performance liquid chromatography (UHPLC) was used to determine levofloxacin in human plasma. The method was found linear over 0.05–10 μg mL−1 with coefficient of correlation equal to 0.9988. The limit of detection and limit of quantification were 0.012 and 0.04 μg mL−1, respectively. At three spiked levels, the precision of proposed method was between 95.3% and 99.7% with intraday and interday relative standard deviations ≤8.9%. Finally, the developed method was used to examine levofloxacin from human plasma of 20 hospitalized patients after transrectal ultrasound-guided prostate biopsy, and the average concentration (±SD) of levofloxacin was 2.35 ± 0.99 μg mL−1 in plasma.

Microwave-assisted synthesis of highly luminescent N- and S-co-doped carbon dots as a ratiometric fluorescent probe for levofloxacin

Uniform N- and S-co-doped carbon dots (NSCDs) with fluorescence quantum yields of up to 64% were synthesized via a one-step microwave-assisted method. Ammonium citrate and L-cysteine act as precursors, and synthesis is completed in 2.5 min using a 750 W microwave oven to give a 62% yield. The NSCDs show bright blue fluorescence (with excitation/emission peaks at 353/426 nm) and have narrow size distribution. On exposure to levofloxacin (LEV), the emission maximum shifts to 499 nm. This effect was used to design ratiometric (2-wavelength) assays for LEV. The fluorometric method (based on measurement of the fluorescence intensity ratio at 499 and 426 nm) has a detection limit of 5.1 μg·L^-1 (3σ/k) and a linear range that extends from 0.01 to 70 mg·L^-1. The method was applied to the determination of LEV in three kinds of spiked water samples and has recoveries in the range from 98.6 to 106.8%. The fluorescent probe described here is highly selective and sensitive. Graphical Abstract Highly luminescent N- and S-co-doped carbon dots were synthesized using AC (ammonium citrate) and Cys (L-cysteine) by microwave-assisted method, and were applied to the visual and ratiometric fluorescence determination of LEV (levofloxacin).

Highly-sensitive detection of eight typical fluoroquinolone antibiotics by capillary electrophoresis-mass spectroscopy coupled with immunoaffinity extraction

An off-line procedure, immunoaffinity extraction (IAE), followed by capillary electrophoresis-mass spectroscopy (CE-MS) has been developed for the simultaneous determination of eight typical FQs in environmental water samples.

An overview of experimental designs in HPLC method development and validation

Chemometric approaches have been increasingly viewed as precious complements to high performance liquid chromatographic practices, since a large number of variables can be simultaneously controlled to achieve the desired separations. Moreover, their applications may efficiently identify and optimize the significant factors to accomplish competent results through limited experimental trials. The present manuscript discusses usefulness of various chemometric approaches in high and ultra performance liquid chromatography for (i) methods development from dissolution studies and sample preparation to detection, considering the progressive substitution of traditional detectors with tandem mass spectrometry instruments and the importance of stability indicating assays (ii) method validation through screening and optimization designs. Choice of appropriate types of experimental designs so as to either screen the most influential factors or optimize the selected factors' combination and the mathematical models in chemometry have been briefly recalled and the advantages of chemometric approaches have been emphasized. The evolution of the design of experiments to the Quality by Design paradigm for method development has been reviewed and the Six Sigma practice as a quality indicator in chromatography has been explained. Chemometric applications and various strategies in chromatographic separations have been described.