Spectrofluorimetric Method Research Articles

Development and Validation of a Sensitive Spectrofluorimetric Method for the Determination of Ibrutinib

Development and Validation of a Sensitive Spectrofluorimetric Method for the Determination of Ibrutinib

Utility of Kolliphor RH 40 in micellar sensitized fluorescence of the novel tyrosine kinase inhibitor “Erdafitinib”: Application to human plasma

Erdafitinib is the first treatment targeting susceptible fibroblast growth factor receptor (FGFR) genetic alterations in patients with locally advanced or metastatic urothelial carcinoma. A simple and precise spectrofluorimetric method was developed for its determination depending on fluorescence enhancement using Kolliphor RH 40 micellar medium at pH 10. The fluorescence intensity was measured at 495 nm after excitation at 410 nm. Different experimental parameters affecting the fluorescence intensity, including type of organized medium, diluting solvent, buffer type and pH were studied during optimization phase. Validation according to ICH Q2(R1) guidance was fully fulfilled. The method was linear over the range of 50 – 800 ng/mL. The lower limit of detection (LOD) and lower limit of quantitation (LOQ) were 14.36 and 43.50 ng/mL, respectively. The relative standard deviation values of intraday and interday precisions were less than 1.93 %. The proposed method was successfully applied to laboratory-prepared tablets. Furthermore, the high sensitivity of the method allowed its application on spiked human plasma samples with a high percent of recovery. The greenness of the method was investigated as an Eco-friendly alternative for erdafitinib determination with minimal organic solvent consumption.

A novel spectrofluorimetric method based on a reaction with an azoisoxazoles-benzenesulfonamide derivative for determination of uranium (VI) ions in water samples.

Selective fluorometric detection and determination of uranium ions is provided here using a novel fluorescent reagent, namely (E)-4-([4-hydroxynaphthalen-1-yl]diazenyl)-N-(5-methyleisoxazol-3-yl) benzenesulfonamide (UVI reagent). The UVI reagent offers a selective fluorescence enhancement behaviour at emission wavelength = 557 nm. The parameters affecting fluorometric detection of uranium ions, such as the pH, solvent type, ligand concentration, interaction time, and interfering ions, were investigated and adjusted. The proposed UVI reagent can detect and determine uranium ions even at low concentrations, for which the obtained limit of detection was 0.1 ppm. Additionally, this proposed determination protocol was successfully used to detect, monitor, and determine uranium ions in actual water samples.

Evaluation of the Interaction of Cinacalcet with Calf Thymus dsDNA: Use of Electrochemical, Spectrofluorimetric, and Molecular Docking Methods.

The binding of drugs to DNA plays a critical role in new drug discovery and is important for designing better drugs. In this study, the interaction and binding mode of calf-thymus double-stranded deoxyribonucleic acid (ct-dsDNA) with cinacalcet (CIN) from the calcimimetic drug that mimics the action of calcium on tissues group were investigated. The interaction of CIN with ct-dsDNA was observed by the differential pulse voltammetry (DPV) technique by following the decrease in electrochemical oxidation signals to deoxyguanosine and adenosine. A competitive study was performed on an indicator, methylene blue, to investigate the interaction of the drug with ct-dsDNA by fluorescence spectroscopy. Interaction studies have shown that the binding mode for the interaction of CIN with ct-dsDNA could be groove-binding. According to the results obtained, the binding constant values were found to be 6.30 × 104 M−1 and 3.16 × 105 M−1, respectively, at 25 °C as obtained from the cyclic voltammetry (CV) and spectroscopic techniques. Possible molecular interactions of CIN with dsDNA were explored via molecular docking experiments. The docked structure indicated that CIN could fit well into the minor groove of the DNA through H-bonding and π-π stacking contact with CIN.

A novel high throughput 96-well-based fluorimetric method to measure amikacin in pharmaceutical formulations: development using response surface methodology.

An aminoglycoside antibiotic, amikacin, is used to treat severe and recurring bacterial infections. Due to the absence of a chromophore, however, amikacin must be extensively derivatized before being quantified, both in analytical and bioanalytical samples. In this study, for the first time, we developed a simple and sensitive method for measuring amikacin sulfate using spectrofluorimetry with a 96-well plate reader, based on the design of the experiment's approach. To develop a robust and reproducible spectrofluorimetric method, the influence of essential attributes, namely pH of the buffer, heating temperature, and concentration of reagents, were evaluated using univariate analysis followed by multivariate analysis (central composite design). International Conference of Harmonization guidelines were used to validate the optimized method. The developed technique is linear from 1.9 to 10μg/ml with a regression coefficient of 0.9991. The detection and quantification limits were 0.649 μg/ml and 1.9μg/ml, respectively. For the developed method, both intraday and interday precision (%RSD) were less than 5%. Using the method, amikacin concentrations were quantified in prepared amikacin liposomes and commercial formulations of Amicin®. The developed method greatly reduces sample volume and is a rapid, high throughput microplate-based fluorescence approach for the convenient and cost-effective measurement of amikacin in pharmaceutical formulations. In comparison with previously published approaches, the suggested method allowed for quick analysis of a high number of samples in a short amount of time (96 samples in 125 sec), resulting in an average duration of analysis of 1.3sec per sample.

A highly sensitive spectrofluorimetric method for the determination of bilastine in its pharmaceutical preparations and biological fluids

Allergic rhinitis and urticaria are extremely prevalent among all age groups. From the clinical experience, usually, an essential second-generation non-sedating H1-antihistaminic drug, such as bilastine is given to relieve allergic symptoms. Bilastine is preferred to be used instead of oral corticosteroids and first -generation sedating H1-antihistaminics to avoid their side effects.A highly sensitive and simple spectrofluorometric method was developed and validated for the determination of bilastine in its dosage forms and biological fluids. The quantum yield was calculated and was found to be as high as 0.48. Aqueous water solution of bilastine gives high native fluorescence emission at 298 nm after excitation at 272 nm. A rectilinear calibration plot was obtained over the concentration range of 1.0–50.0 ng mL−1. The limits of quantitation and detection were 1.0 and 0.33 ng mL−1, respectively. The parameters influencing its spectrofluorimetric behavior, viz, type of solvent, pH and organized media were studied.The proposed method was successfully applied for the determination of the drug in pharmaceutical dosage form and the results obtained were in good agreement with those of given by reported method. The high sensitivity of the proposed method enabled the estimation of the drug in biological matrices, including human plasma and urine samples after simple protein precipitation, and the results obtained were satisfactory.

Bio-analytically fluorimetric method for estimation of ertapenem in real human plasma and commercial samples; application to pharmacokinetics study.

Ertapenem (EPM) has been recently approved by the United States Food and Drug Administration (US-FDA) as an antimicrobial drug. EPM has a broad spectrum of action against different bacterial strains and is most commonly prescribed in Egypt for the treatment of Klebsiella pneumonia. In this study, EPM was estimated using a sensitive and selective spectrofluorimetric method for human plasma and pharmaceutical vials. The measured fluorescence (at 540 nm) was obtained from reaction of EPM with 0.05% w/v benzofurazan (NBD-Cl) using 0.1 M borate buffer pH 8.8 after excitation at 460 nm. The fluorometric linear range was stable from 10 to 350 ng ml-1 . The lower limit of detection and the lower limit of quantitation were found to be 2.13 and 6.47 ng ml-1 respectively. Many factors such as pH, temperature, heating time, and NBD-Cl concentration were optimized. The presented work was validated according to International Council for Harmonisation guidelines and bio-analytically validated using FDA recommendations. The significant finding of this study, sensitivity, was successfully applied in Egypt for a pharmacokinetic application and commercial vials. Pharmacokinetic parameters were studied and the result, recorded as Cmax of EPM, was found to be 83.60 μg ml-1 after infusion of 0.5 g of Invanz® for 30 min. AUC0-∞ was found to be 320 ± 30.2 μ.h ml-1 .

Utilization of N,S-doped carbon dots as a fluorescent nanosensor for determination of cromolyn based on inner filter effect: application to aqueous humour.

A simple and eco-friendly hydrothermal technique is used to prepare water soluble N- and S-co-doped carbon quantum dots probes (N,S-CQDs) from thiosemicarbazide and citric acid. Several characterization techniques were performed to ensure the successful synthesis of highly luminescent N,S-CQDs. The prepared probe exhibited analytical potential as an optical nanosensor for the spectrofluorimetric determination of cromolyn sodium (CRO) in its pharmaceutical dosage forms and aqueous humour. The emission intensity of the synthesized N,S-CQDs was measured at 411 nm after excitation at 345 nm. Addition of increasing concentrations of CRO to N,S-CQDs led to quenching of its fluorescence intensity. CRO was investigated within a wide concentration range 10.0-150.0 μM with a limit of detection of 2.0 μM and a limit of quantification of 6.0 μM. The quenching of fluorescent N,S-CQDs occurred through the inner filter effect (IFE). The developed spectrofluorimetric method was successfully optimized and validated according to the International Council of Harmonisation guidelines (ICH). The method greenness is proved through using both Eco-Scale and AGREE approaches.

Chip-Based Spectrofluorimetric Determination of Iodine in a Multi-Syringe Flow Platform with and without In-Line Digestion-Application to Salt, Pharmaceuticals, and Algae Samples.

In this work, a flow-based spectrofluorimetric method for iodine determination was developed. The system consisted of a miniaturized chip-based flow manifold for solutions handling and with integrated spectrofluorimetric detection. A multi-syringe module was used as a liquid driver. Iodide was quantified from its catalytic effect on the redox reaction between Ce(IV) and As(III), based on the Sandell–Kolthoff reaction. The method was applied for the determination of iodine in salt, pharmaceuticals, supplement pills, and seaweed samples without off-line pre-treatment. An in-line oxidation process, aided by UV radiation, was implemented to analyse some samples (supplement pills and seaweed samples) to eliminate interferences and release iodine from organo-iodine compounds. This feature, combined with the fluorometric reaction, makes this method simpler, faster, and more sensitive than the classic approach of the Sandell–Kolthoff reaction. The method allowed iodine to be determined within a range of 0.20–4.0 µmol L−1, with or without the in-line UV digestion, with a limit of detection of 0.028 µmol L−1 and 0.025 µmol L−1, respectively.

An eco- friendly, selective, and sensitive spectrofluorimetric method for the quantification of Dolutegravir in its bulk and tablet dosage form

This study is concerned with assessing the bulk and tablet dosage forms of Dolutegravir (DTG) by means of a novel yet simple environmentally friendly spectrofluorimetric method that features fast response and high sensitivity compared to the time consuming HPLC methods and the lower sensitivity spectrophotometric ones. The method relies mainly on measuring the native fluorescence of Dolutegravir in water at an emission of 415 nm after excitation at 262 nm. The method shows rectilinear fluorescence–concentration relation over Dolutegravir concentration range of 0.2–1.2 µg/mL at the emission maxima, with detection limit of 0.020 µg/mL and quantification limit of 0.061 µg/mL. The results of the proposed method were compared with those obtained by applying the comparison method and the two sets coincided harmoniously. In addition, the method was validated in accordance with ICH guidelines for linearity, accuracy, precision, specificity, and robustness.

Hantzsch condensation reaction as a spectrofluorometric method for determination of alogliptin, an antidiabetic drug, in pure form, tablet form, and human and rat plasma.

To analyze alogliptin in its pharmaceutical dosage forms and human plasma, a sensitive, inexpensive, simple, and precise spectrofluorimetric method was developed and tested. This method was also used to investigate the drug's pharmacokinetic behaviour in the blood of rats. This was based on the Hantzsch reaction, which produces yellowish luminous products that can be detected spectrofluorometrically at 480 and 415 nm for emission and excitation, respectively, when the primary amine group in the examined drug reacts with acetylacetone and formaldehyde. Several experimental parameters that affect the reaction product's development and stability were explored and improved. The curve of fluorescence and concentration for alogliptin was linear in the concentration range 0.05-3.60 μg ml-1 . The proposed approach was validated according to International Council for Harmonization criteria. The method was successfully utilized to evaluate the examined drug in dose formulations and spiked human plasma with high accuracy.

Assay of new combination of tamsulosin and tadalafil using synchronous spectrofluorimetric method coupled with mathematical tools

A fixed-dose combination therapy of tamsulosin andtadalafilis now available for treatmentof lower urinary tract symptoms associated with benign prostatic hyperplasia. The decrease in sexual performance which is a side-effect of tamsulosin can be compensated by using tadalafil. This study is the first to develop and optimize a synchronous spectrofluorimetric method coupled with derivative and derivative ratio mathematical tools for the determination of tamsulosin andtadalafil in their newly released dosage form. The method successed in quantification of tadalafil by measuring the second-order derivative synchronous spectrofluorimetric amplitude at 278 nm (corresponding to zero‐crossing of tamsulosin) using Δƛ=11 nm. On the other hand, first derivative ratio synchronous spectrofluorimetric peak amplitude was measured at 260 nm for determination of tamsulosin, using Δƛ=15 nm and divisor concentration of 0.1 µg mL−1. The method validation was performed using ICH guidelines. The linear responses of tamsulosin andtadalafil were from 0.04 to 0.5 and 0.05–0.5 µg mL−1, respectively. High sensitivity was achieved as represented by slope values of 0.32 and 608.4 for tamsulosin andtadalafil, respectively. The method is sensitive enough to detect concentration as low as 0.024 for both drugs. The proposed integrated spectrofluorimetric method showed good simplicity, selectivity and greenness. It can be successfully applied for analysis of both drugs in dosage form.

Development, Validation and Application of a Spectrofluorimetric Method for the Quantification of Nevirapine in Pharmaceutical Formulations Tablets and Suspensions

The development of the spectrofluorimetric method can be considered a promising alternative that is relatively less expensive and sufficiently reliable. In the current literature, no method for the analysis of nevirapine by spectro-fluorimetric has been reported. The proposed method is based on the transformation of naturally non-fluorescent nevirapine into a fluorescent derivative after chemical synthesis. Maximum excitation and emission wavelengths are 290 nm and 357 nm respectively. The analytical performance of the method demonstrates linearity in the concentration range 1.5 × 10-2 and 13.5 × 10-2 μg/mL with a correlation coefficient (r) greater than 0.999. The detection (LOD) and quantification (LOQ) limits found are 1.97 × 10-3 μg/mL and 5.48 × 10-3 μg/mL respectively. Recovery is achieved with 99.9% and 100.3% trueness, intra-day precision with a coefficient of variation of repeatability (CVr) of 0.99% and inter-day precision with a coefficient of variation of precision (CVR) of 1.7%. The method has been successfully applied in the analysis of 10 batches of nevirapine tablets and suspensions.

A highly selective and sensitive spectrofluorimetric method for the assessment of 3-nitrotyrosine in serum using (Eu(TTA)3Phen) photo probe.

A simple, accurate and fast method was developed for the assessment of 3-nitrotyrosine as a biomarker for the early diagnosis of liver cirrhosis with minimal hepatic encephalopathy (MHE) using a (Eu(TTA)3Phen) photo probe. 3-Nitrotyrosine can remarkably quench the luminescence intensity of the (Eu(TTA)3Phen) complex in DMSO at pH = 9 and λem = 617 nm. The quenching of the luminescence intensity of (Eu(TTA)3Phen) complex particularly the electrical emission band at λem = 617 nm is used for the assessment of 3-nitrotyrosine in different serum samples of patients with liver cirrhosis.

Spectrofluorimetric Determination of Some N. Containing Medicines Using Rhodamine 6G as a Chromogenic Reagent

A sensitive spectrofluorimetric method has been developed for the analysis of some medicines containing primary, secondary, and tertiary amino groups, namely Diclofenac (DIC), Domperidone (DOM), Famotidine (FAM), and Propranolol (PRO), in their pure and medicinal forms. The method is based on the quenching of the fluorescence intensity of rhodamine 6G (R6G) through the formation of ion-pair complexes between the above medicines and the R-6G reagent, which is measured at 552 nm after excitation at 402 nm. The calibration graphs were rectilinear in the concentration ranges of 0.10- 9.00, 0.05-15.00, 0.10-14.0 and 0.05-5.00 µg mL-1 for above medicines respectively. The recovery (%) values were ranged between 99.45%- 100.97%. The detection limits ranged in the concentration of 0.243-0.754 µg/mL, and the limits of quantitation were 0.806- 2.420 µgmL-1 for all drugs. The method was successfully applied for the determination of these drugs in their pharmaceutical preparations.

Benzofurazan -based fluorophore for the spectrofluorimetric determination of 6-Aminocaproic acid: Application to spiked human plasma and urine

6-Aminocaproic acid is one of the most widely used antihemorrhagic and antifibrinolytic agent, therefore, it is essential to create a novel, sensitive, low cost and straightforward spectrofluorimetric method for its determination. The nucleophilic substitution interaction between the primary amine of 6-aminocaproic acid with 4-chloro-7-nitro benzofurazan (NBD-Cl) generated a yellow product. The reaction proceeded in borate buffer (pH 9) and its fluorescence has been measured at 525 nm after excitation at 472 nm. All of the parameters that have impact on the performance of the developed method were investigated and optimized. The range of linearity was 0.1–0.7 μg/mL while, the quantitation limit was down to 0.101 μg/mL and limit of detection was 0.033 μg/mL. This approach was effectively employed to evaluate the content of 6-aminocaproic acid in laboratory prepared dosage form with average percentage recovery of 100.19 ± 0.72% without any interference from basic excipients. Moreover, the proposed method was extended to determine 6-aminocaproic acid in spiked human plasma and urine.

A novel spectrofluorimetric method for determination of lomefloxacin adopting on zinc(II) chelation strategy: Application in human plasma.

A new sensitive and instantaneous spectrofluorimetric method for efficient determination of lomefloxacin (LMX) in its pure, dosage form and human plasma was designed. The developed method depends on formation of a metal-chelation compound of LMX as a ligand with zinc(II) in a buffer of acetate (pH5.5). The following parameters; type of metal, concentration of metal, pH, type of buffer and diluting solvent were optimized. After carefully investigation; 0.2mM zinc, 2.0ml acetate buffer (pH 5.5) and water as diluting solvent were set as optimum reaction conditions. Under these conditions, a large increase in the intensity of the fluorescence of LMX was attained at 450 after excitation at 284 nm. The limits of detection and quantification were 5.8 and 1.9 ng ml-1 , respectively, with linearity range of 10.0 to 500.0ng ml-1 . The binding mode of LMX and zinc(II) ion (Zn2+ ) was found to be 2:1, respectively, and confirmed by Job's plot method. Furthermore, it extended to the analysis of LMX in the spiked plasma of humans with percentage recovery (98.70 ±0.97 to 100.30 ±1.69%, n=3).

Micellar-Enhanced Spectrofluorimetric Method for Quantification of Diclofenac Potassium in Pure Form, in Pharmaceutical Preparations and Human Plasma

Abstract A rapid, simple and economical spectrofluorimetric method for the determination of diclofenac potassium in pure form, in pharmaceutical preparations and in human plasma has been developed. The method is based on the enhancement of the fluorescence signal of diclofenac potassium by the addition of sodium dodecyl sulphate in McIvaine buffer with a pH of 5. Different experimental conditions such as buffer type, pH, type and concentration of surfactants were investigated. The fluorescence intensity of the solution was recorded at 361 nm after excitation at 243 nm. The method shows linearity in the concentration range of 0.2 μg mL–1–10 μg mL–1 with a good correlation coefficient of 0.997. The relative standard deviation value was 3.62 (n = 7). The limit of detection and limit of quantification were calculated to be 2.84 × 10–3 μg mL–1 and 9.47 × 10–3 μg mL-1, respectively. The effect of excipients and co-administrated drugs was investigated and no interference was observed. The method was successfully applied for the determination of diclofenac potassium in pure form, in pharmaceutical products and in human plasma. The percentage recoveries obtained ranged from 100.25% to 102.16% for pure form and 97.50% to 102.00% for pharmaceutical products and from 98.50% to 101.67% for human plasma.

Orthophthaldehyde as a fluorescent probe for the feasible and sensitive assay of heptaminol: application to dosage forms and real human plasma.

The antihypotensive drug heptaminol was determined using a spectrofluorimetric method and ortho-phthaladehyde as a fluorescence probe. The drug was mixed with the reagent in the presence of 2-mercaptoethanol and the reaction was carried out in slightly alkaline aqueous solution containing 0.1 M sodium hydroxide. The resulting product exhibited high fluorescence activity that was measured at 451 nm after excitation at 334 nm. The linearity range of the method was 5-100 ng ml-1 with a lower detection limit of 1.8 ng ml-1 . The procedure was evaluated according to the International Council of Harmonization guidelines. The proposed method was applied to analyze the drug in pharmaceutical tablets and oral drops. In addition, the present study represents the first spectrofluorimetric method for the determination of the cited drug in real human plasma. The method provided high recovery percentages without any interference from coexisting pharmaceutical excipients or the components of human plasma.

Reactions of water-soluble binuclear tetranitrosyl iron complexes of the μ-S structural type with adenosine triphosphoric acid: Kinetics and reaction mechanism

The reactions of adenosine triphosphoric acid (ATP) with water-soluble binuclear tetranitrosyl iron complexes of the μ-S structural type with functional sulfur-containing ligands (thiosulfate (1) cysteamine (2), and penicillamine (3)) afford products of close structures. The hydrolysis products of the complexes (1–3) in aqueous aerobic solutions are studied by amperometry and mass electrospectrometry. The kinetic regularities of the reactions of the complexes (1–3) with ATP are studied by the spectrofluorimetric method. A generalized kinetic model describing the experimental data of three reactions is proposed for the process. From the qualitative point of view, the reactions of ATP with the studied complexes occur similarly in spite of the difference in the ligands. The rates of particular steps of the process depend on the nature of the ligands. The values determined for the kinetic parameters quantitatively characterize the influence of the ligand nature in complexes 1–3 on the reactivity toward ATP and increase in the order: cysteamine < penicillamine < thiosulfate.