Sensitive Spectrofluorimetric Method Research Articles

Eco-friendly second derivative synchronous fluorescence spectroscopic method for simultaneous determination of rosuvastatin and ezetimibe in pharmaceutical capsules

The fixed dose combination of Rosuvastatin and ezetimibe has recently received approval from the FDA for the treatment of elevated levels of low-density lipoprotein cholesterol in adults. Herein, an eco-friendly and highly sensitive spectrofluorimetric method was developed and validated for simultaneous determination of rosuvastatin and ezetimibe in commercial capsules. The developed method involved synchronous fluorescence spectroscopy combined with second derivative spectroscopy to resolve the overlapping fluorescence spectra of rosuvastatin and ezetimibe. The studied drugs were measured in synchronous mode at Δλ of 40 and their recorded synchronous fluorescence spectra were derivatized into second-order spectra, enabling the selective quantification of rosuvastatin and ezetimibe at 370 nm and 312 nm, respectively. Optimization studies regarding to the influence of buffer pH, incorporation of surfactant, choice of diluting solvent, and synchronous Δλ were carried out. The method was validated using the validation characteristics listed in ICH Q2(R1). The calibration curves displayed satisfactory linear relationships across the calibration range of 0.1–2 µg/mL for rosuvastatin and 0.05–3 µg/mL for ezetimibe. The methodology demonstrated robustness to minor modifications in the procedural parameters and selectivity in quantifying the studied drugs in synthetic mixed solutions and commercial capsules without interference. Furthermore, the level of environmental friendliness and sustainability of the suggested spectrofluorimetric approach was assessed in relation to two previously documented methodologies utilizing the AGREE metric. The findings indicated that the suggested method demonstrated a notably superior level of sustainability in comparison to the documented methods.

Eco-friendly spectrofluorimetric determination of peramapanel; application in pharmaceutical dosage forms and spiked human plasma

A rapid and sensitive spectrofluorimetric method has been developed for the determination of perampanel in pharmaceutical preparations (assay method) and human plasma (bioanalytical method). The fluorescent product was measured at an excitation wavelength (λex) 294 nm and emission wavelength (λem) 430 nm. The assay method was validated as per the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) Q2(R1) guidelines. For the assay method, the fluorescence intensity versus concentration plot was found to be linear over the concentration range 25–175 ng/mL.In case of bioanalytical method, for the extraction of drug from human plasma, a lucid liquid-liquid extraction method using ethyl acetate was employed. The bioanalytical method was validated according to the United States Food and Drug Administration (USFDA) guidelines and it was applied for the quantification of the drug in human plasma with reasonable accuracy and precision. For the bioanalytical method, the fluorescence intensity versus concentration plot was found to be linear over the concentration range 5–150 ng/mL. The impact of endogenous compounds of the plasma matrix on drug fluorescence was also assessed. To assess the greenness of the developed method, Green Analytical Procedure Index (GAPI) and Analytical GREEnness (AGREE) tools were applied and it was inferred that the developed method adheres closely to the principles of green analytical chemistry.

A highly sensitive spectrofluorimetric method for the determination of bilastine in human plasma: Application of content uniformity testing.

Bilastine, a new second generation antihistaminic drug, has been widely used for relieving symptoms of allergic rhinitis and urticaria without a sedative effect. A simple, cost-effective, and highly sensitive fluorimetric method was developed for the estimation of bilastine in human plasma, in addition to its pure state and tablets. The suggested method depended on binary complex formation of eosin with bilastine in a buffered medium at pH 4.2. The formed complex resulted in quantitative quenching of eosin emission at 538 nm after excitation at 335 nm. This method demonstrates a broad range of linearity, spanning from 200 to 1000 ng/mL, and exhibits exceptional sensitivity, with a limit of detection and quantitation of 30.85 and 93.48 ng/mL, respectively. In addition, this spectrofluorimetric method may be employed to determine the amount of bilastine in human plasma and tablets with satisfactory accuracy and excellent precision. Furthermore, the content uniformity of bilastine in commercially available tablets was successfully tested by this approach. Compared with the reference method, there were no significant variations in terms of precision or accuracy. In conclusion, the proposed protocol is highly recommended to quantitatively estimate bilastine in different quality control settings.

In-vivo pharmacokinetic study of ibrutinib-loaded nanostructured lipid carriers in rat plasma by sensitive spectrofluorimetric method using harmonized approach of quality by design and white analytical chemistry

Ibrutinib, an antineoplastic agent tackling chronic lymphocytic leukemia, mantle cell lymphoma, and Waldenstrom’s Macroglobulinemia, falls under the category of BCS class II drugs, characterized by a puzzling combination of low solubility and high permeability. Its oral bioavailability remains a perplexing challenge, merely reaching 2.9 % due to formidable first-pass metabolism hurdles. In a bid to surmount this obstacle, researchers embarked on a journey to develop ibrutinib-loaded NLCs (Nanostructured Lipid Carriers) using a methodology steeped in complexity: a Design of Experiments (DoE)-based hot melted ultrasonication approach. Despite a plethora of methods for analyzing ibrutinib in various matrices, the absence of a spectrofluorimetric method for assessing it in rat plasma added to the enigma. Thus emerged a spectrofluorimetric method, embodying principles of white analytical chemistry and analytical quality by design, employing a Placket-Burman design for initial method exploration and a central composite design for subsequent refinement. This method underwent rigorous validation in accordance with ICH guidelines, paving the way for its application in scrutinizing the in-vivo pharmacokinetics of ibrutinib-loaded NLCs, juxtaposed against commercially available formulations. Surprisingly, the optimized NLCs exhibited a striking 1.82-fold boost in oral bioavailability, shedding light on their potential efficacy. The environmental impact of this method was scrutinized using analytical greenness tools, affirming its eco-friendly attributes. In essence, the culmination of these efforts has not only propelled advancements in drug bioavailability but also heralded the dawn of a streamlined and environmentally conscious analytical paradigm.

Diaryl pyrrolone fluorescent probing strategy for Mirabegron determination through condensation with ninhydrin and phenylacetaldehyde: Application to dosage forms, human urine and plasma

Mirabegron (MRB) is a β3-adrenoceptor agonist used for managing overactive bladder syndrome. A cost-effective, environmentally friendly, and highly sensitive spectrofluorimetric method was suggested to serve the purpose of quantifying MRB in its pure state, pharmaceutical tablets, spiked human plasma and urine, and testing content uniformity. In the present study, ninhydrin and phenylacetaldehyde react with the amino group moiety of MRB in Teorell-Stenhagen buffer (pH 7.5) to generate a strongly fluorescent diaryl pyrrolone compound that emits fluorescence at a wavelength of 477 nm upon excitation at 385 nm. The obtained calibration curve showed a linear relationship with a high correlation coefficient (r = 0.9997) in the concentration range of 0.25 to 5.0 µg mL−1. Limits of detection (LOD) and quantitation (LOQ) were 0.082 and 0.248 µg mL−1 respectively. The procedure was verified in accordance with the ICH guidelines. The suggested approach could be utilized for the selective analysis of MRB in its pharmaceuticals, either containing a single drug or co-formulated with solifenacin succinate. The greenness of the suggested method was confirmed using different green analytical metrics.

Integrated approach of white analytical chemistry and design of experiments to microwave-assisted sensitive and eco-friendly spectrofluorimetric estimation of mirabegron using 4-chloro-7-nitrobezofuran as biosensing fluorescent probe

The USFDA recently approved mirabegron, a novel once-daily β-3 adrenoceptor agonist for oral administration, as a transformative treatment for overactive bladder. Despite the existence of numerous analytical methods for the assay and bioanalysis of mirabegron, it’s perplexing that none have explored the domain of microwave-assisted sensitive spectrofluorimetric method for mirabegron estimation, even after extensive literature review. Adding to the enigma is the insistence of current analytical methods on using expensive and harmful organic solvents, posing a threat to marine life and the broader environment. Recently, the white analytical chemistry approach has been introduced to develop analytical methods that are cost-effective, environmentally friendly, and user-friendly. Consequently, a white analytical chemistry-based, sensitive, and eco-friendly spectrofluorimetric estimation of mirabegron has been initiated, using 4-Chloro-7-nitrobenzofurazan as a fluorescent biosensing probe. The development of this robust method involved a series of experiments designed to minimize solvent and time wastage. Through a combination of fractional factorial and Box-Behnken designs, researchers identified the critical variables and optimized the method to perfection. This method was validated according to the stringent ICH Q2 (R2) and USFDA guidelines, ensuring its reliability and accuracy. Once approved, this sensitive spectrofluorimetric method was tested, accurately estimating mirabegron levels in commercial formulations and rat plasma samples. To further enrich the study, a comprehensive evaluation of existing analytical methods was conducted alongside the proposed spectrofluorimetric method, using advanced tools like the AGREE calculator, GAPI software, and RGB model to assess their eco-friendliness and effectiveness in mirabegron estimation.

Green spectrophotometric and spectrofluorimetric determination of biperiden hydrochloride using erythrosine B sensing probe.

Erythrosine B (EB) is a food colorant antiviral xanthene dye that has many applications as a color additive in pharmaceuticals and cosmetics. Its use as a sensor for spectrofluorimetric and spectrophotometric analysis of amine-based pharmaceuticals renders many advantages because of its availability, low cost, rapid labeling, and high sensitivity. Herein, two fast and sensitive spectrofluorimetric and spectrophotometric methods were established for the estimation of the anti-Parkinson drug, biperiden (BIP) hydrochloride (HCl), in its raw material and tablet forms. The proposed methods depended on the interaction between the phenolic group of EB and the tertiary amino group of the studied analyte to form an ion-pair complex at pH4 using the Britton Robinson buffer. The spectrofluorimetric method is based on the measurement of the quenching power of BIP HCl on the fluorescence intensity of EB at λex/em= 527.0/550.9nm. This method was rectilinear over the concentration range of 0.1-1.0μg/mL with a limit of detection (LOD) = 0.017 μg/mL and a limit of quantification (LOQ) = 0.05 μg/mL. Meanwhile, the colorimetric method involved monitoring the absorbance of the formed ion-pair complex at 555 nm, showing a linearity range of 0.4-5.0μg/mL with LOD = 0.106 μg/mL and LOQ = 0.322 μg/mL. The proposed methods were assessed for the greenness, indicating the greenness of the developed methods.

Derivatization-free CTAB-induced fluorescence sensing strategy for determination of daptomycin in environmental, pharmaceutical, and biological samples

A simple, economical, green, and sensitive spectrofluorimetric method was developed for the determination of the cyclic lipopeptide antibiotic daptomycin (DPT). The method is based on the sensitizing effect of the cationic surfactant cetyltrimethylammonium bromide (CTAB) on the weak fluorescent signal of DPT. After excitation at 373 nm, DPT-CTAB fluoresces at a maximum intensity of 458 nm. Under the optimized conditions, the method exhibits linearity over the concentration range of 0.50–10.0 μg/mL with a detection limit down to 0.11 μg/mL. The study revealed excellent selectivity towards DPT in the presence of the co-administered drugs. The proposed method was able to determine DPT in its commercial vials, and the results were comparable to those obtained by the reported method. The high sensitivity of the developed method allowed its estimation in water and biological fluids (spiked plasma and urine samples) with high % recoveries (95.89–105.99%). DPT was successfully determined in rat plasma after intra-peritoneal administration, and the method was applied for the calculation of its pharmacokinetic parameters (Cmax, t1/2, tmax, and AUC) in rat plasma. Comparison with the reported methods reveals many benefits of the proposed spectrofluorimetric method, such as greenness, simplicity, sensitivity, and reliability. Finally, different recent assessment tools confirmed the greenness and whiteness of the proposed method.

Comprehensive strategy of white analytical chemistry and analytical quality by design to sensitive spectrofluorimetric method for in-vitro drug release kinetic study of Ibrutinib-loaded nanostructured lipid carriers for leukemia via lymphatic targeting

Ibrutinib (IBR) is a drug classified as BCS class II, characterized by low solubility and high permeability. However, its oral bioavailability is limited to a mere 2.9% due to significant first-pass metabolism. To address this challenge, researchers developed IBR-NLCs (Nanostructured Lipid Carriers) using a DoE-based hot melted ultrasonication method to enhance its bioavailability and drug release profile. While various methods exist for IBR analysis in pharmaceutical formulations, human plasma, and rat plasma, a sensitive spectrofluorimetric method has not been reported for estimating IBR. To facilitate in-vitro drug release kinetic studies of IBR-NLCs, a sensitive and green spectrofluorimetric method was developed, combining principles of white analytical chemistry and analytical quality by design. This approach included a fractional factorial design for screening of method variables and a Box-Behnken design for method optimization. The developed method underwent rigorous validation following ICH guidelines. The developed method was applied to assess the in-vitro drug release kinetic study of IBR-NLCs in comparison to marketed formulations. Remarkably, the optimized IBR-NLCs exhibited sustained release of IBR which helps to decrease dose and dose frequency. The whiteness and greenness profiles of published and proposed method have been assessed using analytical greenness calculator, green analytical procedure index software, national environmental method index standards, and eco-scale assessment tool. The results confirmed that the proposed method is sensitive, eco-friendly, cost-effective, speedy, and user-friendly, making it an excellent choice for IBR estimation in NLCs. In summary, the developed method for drug release kinetic study of BR-NLCs, utilizing principles of white analytical chemistry and analytical quality by design, has not only improved drug release profile but also resulted in an efficient and environmentally friendly analytical approach.

Application of a nucleophilic substitution reaction for spectrofluorimetric determination of aripiprazole in pharmaceutical dosage form and plasma matrix; greenness assessment

Aripiprazole is an antipsychotic medicine used to treat a variety of mental disorders, including irritability linked with autism disorder in children. Herein, a green and highly sensitive spectrofluorimetric method was developed for the determination of aripiprazole in pharmaceutical dosage form and plasma matrix. The method based on the formation of a fluorescent adduct from the nucleophilic substitution reaction of 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole (NBD-chloride) with aripiprazole, which can be detected at 542 nm following excitation at 481 nm. Factors that affect the development and fluorescence sensitivity of the reaction product were investigated and optimized. The reaction yielded the most optimal fluorescence responses when it was performed using 1.5 mL of 0.2 % w/v NBD-chloride, 1.5 mL of borate buffer pH 9, heating at 80 °C for 20 min, and ethanol as a diluting solvent. The method was validated as per ICH guidelines for analytical and bioanalytical procedures. Good linearity was established between the fluorescence responses of the reaction product and aripiprazole concentrations in the range of 100–1200 ng/mL with adequate accuracy and precision results. The applied method was very sensitive and selectively determined aripiprazole in pharmaceutical and plasma matrices with no interferences. Furthermore, the compliance of the proposed method with the principles of green analytical chemistry was evaluated in comparison with the reported method using analytical eco-scale and AGREE metrics. The outputs proved that the proposed method complied more with the principles of green analytical chemistry than the reported method.

Validated spectrofluorimetric assay of two co-administered drug mixtures containing hydroxychloroquine with either moxifloxacin or ofloxacin as a drug regimen for hospital-acquired pneumonia in covid-19 patients.

Moxifloxacin and ofloxacin are two broad-spectrum quinolone antibiotics. They are among the most widely used antibiotics nowadays in controlling the covid-19 pandemic. Hydroxychloroquine is an FDA-approved drug for the treatment of covid-19. This work describes a simple, green, selective, and sensitive spectrofluorimetric method for the assay of moxifloxacin and ofloxacin in presence of hydroxychloroquine as two co-administered mixtures used in the treatment of hospital-acquired pneumonia in the covid-19 patients. Simultaneous assay of hydroxychloroquine and moxifloxacin was carried out in methanol by direct spectrofluorimetric method (method I) at 375 nm and 550 nm respectively after excitation at 300 nm. The direct spectrofluorimetric assay was rectilinear over concentration range of (50.0-400.0) and (300.0-2500.0) ng/ml for hydroxychloroquine and moxifloxacin with LOD of 6.4 and 33.64 ng/ml and LOQ of 19.4 and 102.6 ng/ml for the two drugs respectively. While the assay of hydroxychloroquine and ofloxacin was carried out by measuring the first derivative synchronous amplitude for hydroxychloroquine at the zero crossing point of ofloxacin and vice versa at Δ λ = 140 nm (method II). Hydroxychloroquine was measured at 266 nm while ofloxacin at 340 nm over concentration range of (4.0-40.0 ng/ml) for hydroxychloroquine and (200.0-2000.0 ng/ml) for ofloxacin with LOD of 0.467 ng/ml and 25.3 ng/ml and LOQ of 1.42 ng/ml and 76.6 ng/ml for the two drugs respectively. the two methods were validated following ICH guidelines and were applied to the analysis of the two drugs in plasma with good percent recoveries (109.73-93.17 %).

Procalcitonin assessment by using optical sensor terbium hydrochlorothiazide complex for early diagnosis of lung cancer

A simple, selective and sensitive spectrofluorimetric method has been reported in this paper for the assessment of procalcitonin (PCT) as a biomarker in serum samples of cancer patients by using optical sensor Tb3+-hydrochlorothiazide (Tb3+-HCTZ) complex. The method based on the quenching of the luminescence intensity of Tb3+-HCTZ complex by addition of different concentrations of PCT. The optical sensor was synthesized and characterized by absorption and fluorescence measurements. The performance of the designed sensor is determined through monitoring the quenching of the fluorescence intensity at 545 nm by (PCT) after excitation at 320 nm and pH = 7 in DMSO. The calibration of this method was performed in the concentration range of (3.37–100.62 ng/mL) with a limit of detection (LOD) and quantitation limit of detection (LOQ) are (0.038 and 0.114) ng/mL, respectively and a correlation coefficient of (0.98). This method was practical, simple and relatively free from interference effect. It was successfully applied to measure PCT in samples of human serum and from this method we can assess some biomarkers of cancer related diseases in human body.

Green synthesized nitrogen-doped carbon quantum dots for the sensitive determination of larotrectinib in biological fluids and dosage forms: Evaluation of method greenness and selectivity

Recently, the kinase receptor inhibitor drug larotrectinib has been approved as a monotherapy for the treatment of patients with solid tumors containing the neurotrophic receptor tyrosine kinase gene fusion. In this paper, a novel sensitive spectrofluorimetric method was proposed for the determination of larotrectinib based on nitrogen-doped carbon quantum dots (N-CQDs) fluorescent probes. The proposed method is the first spectroscopic method for analysis of the cited drug, which is simple to implement and involves no pre-treatment steps or complicated techniques. The N-CQDs synthesis was performed by adopting a straightforward, fast, and environmentally friendly approach. It was achieved by means of a standard domestic microwave with inexpensive and readily available starting materials: orange juice (carbon source) and urea (nitrogen source). The synthesized N-CQDs were subjected to microscopic and spectroscopic characterization procedures. They were found to be stable with a sufficiently high fluorescence quantum yield (25.3%) and a small particle size distribution (2–5 nm). The motivation for the use of N-CQDs in this study arose from their excellent fluorescence intensities at 417 nm when excited at 325 nm. Larotrectinib was found to have a quantitative and selective quenching effect on the QDs fluorescence allowing for its sensitive determination. The drug’s quenching mechanism was investigated and found to be of the static type. Under optimal conditions, the proposed approach permitted the determination of larotrectinib over the concentration interval of 5.0–28.0 µg/mL. The method showed sufficient sensitivity with a detection limit of 0.19 µg/mL and a quantitation limit of 0.57 µg/mL, enabling the determination of LARO in spiked human plasma samples. The approach’s recovery percentage was found to be in the range of 99.09–100.73% for pure samples and 97.35–102.59% for plasma samples. The study also successfully applied the proposed approach to the commercial oral solution form of larotrectinib (Vitrakvi®) with high selectivity. Method greenness was further evaluated by adopting two metric tools, including the complementary green analytical procedure index (ComplexGAPI) and Analytical GREENNESS metric approach (AGREE), and it was confirmed to be excellent green. The proposed method was validated in accordance with the ICHQ2 (R1) recommendations and is considered an excellent candidate for potential application in the therapeutic monitoring of larotrectinib.

Determination of doxepin hydrochloride in spiked human plasma and capsule after derivatization with eosin Y using resonance Rayleigh scattering, second-order scattering and frequency doubling scattering methods.

Doxepin hydrochloride (DOX) is a tricyclic antidepressant drug. Three sensitive spectrofluorimetric methods, namely resonance Rayleigh scattering (RRS), frequency doubling scattering (FDS) and second-order scattering (SOS), were developed and validated for their estimation of doxepin in spiked human plasma and formulation using liquid-liquid extraction method through the formation of an ion pair complex with eosin Y at a pH of4.5. Various factors affecting fluorescence intensity were optimized, and the reaction kinetics was determined using the Arrhenius equation method. Different scattering methods such as RRS, FDS and SOS were developed at maximum scattering wavelengths λex /λem = 567/567 nm for RRS, 720/360 nm for SOS and 260/520 nm for FDS, respectively. The methods exhibited high sensitivities, and the detection limits for DOX were found to be 0.82, 1.20 and 1.03 ng/ml for RRS, FDS and SOS methods, respectively. The FDS method exhibited the highest sensitivity. The methods were validated using the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use guidelines and applied to determine DOX in capsule and spiked human plasma samples.

Highly sensitive spectrofluorimetric method for the determination of the genotoxic methylglyoxal in glycerol-containing pharmaceuticals and dietary supplements.

Methylglyoxal (MGO) is a genotoxic α-dicarbonyl compound. Recently, it was found to be formed in glycerol preparations during storage through auto-oxidation. A simple fluorimetric determination of the carcinogenic degradation product of glycerol, MGO, was developed and validated. The proposed method is based on the derivatization of MGO with 4-carbomethoxybenzaldehyde (CMBA) and ammonium acetate to yield a fluorescent imidazole derivative that can be measured at 415 nm after excitation at 322 nm. The optimized conditions were determined to be 0.2M CMBA, 1.0M ammonium acetate and a reaction time of 40 min at 90°C using ethanol as diluting solvent. The linear range was 10.0-200.0ng/ml. Detection and quantification limits were 2.22 and 6.72 ng/ml, respectively. The proposed method was validated according to International Council for Harmonisation (ICH) guidelines and compared with the reported method and no significant difference was found. It was successfully applied for the determination of MGO in six different glycerol-containing pharmaceutical preparations and dietary supplements.

Novel sensing probe using Terbium-sensitized luminescence and 8-hydroxyquinoline for determination of prucalopride succinate: green assessment with Complex-GAPI and analytical Eco-Scale

A highly sensitive spectrofluorimetric method is developed for the determination of prucalopride succinate (PRU). The method depends on lanthanide-sensitized luminescence due to complex formation between the drug and terbium chloride (Tb+3) which is enhanced by the addition of 8 hydroxyquinoline (8HQ) and phosphate buffer (0.02 M, pH 3.2). The calibration curve was constructed over the linear range 10–300 ng/mL after excitation at 226 nm and measuring the emission of the ternary complex at 544 nm. The method was validated according to ICH Q2 (R1) guidelines and showed a good recovery ± RSD of 100.41% ± 1.26, the limits of detection and quantitation were found to be 2.81 and 8.53 ng/mL, respectively. The proposed method was successfully applied for the determination of the drug marketed tablet dosage form and the results were in good agreement with the reference method. Also, the method greenness was evaluated according to Complex-GAPI and analytical Eco-Scale.

Highly selective and sensitive spectrofluorimetric method for determination of cypermethrin in different environmental samples.

A sensitive, selective, and simple spectrofluorimetric method for the detection and determination of cypermethrin (CYP) in various samples based on thioglycolic acid-caped Mn-doped ZnS quantum dots (TGA@Mn-ZnS-QDs)is reported. These quantum dots were synthesized using the Gonzalez method. The synthesized quantum dots were structurally characterized with the help of different spectroscopic techniques including X-ray diffraction (XRD) and energy dispersive X-ray (EDX) techniques and fluorescence spectroscopy. The quantum dots were used for spectrofluorimetric detection and determination of CYP. The emission peak of these quantum dots at 632nm showed a linear quenching with increasing the concentration of CYP, noticing an excellent linear relationship between F°/F values and CYP in the range of 0.5-12µgmL-1 with a correlation coefficient (R2) of 0.992. The influence of different physiochemical parameters such as time, pH, the concentration of quantum dots, and other pesticides interference on the fluorescence quenching was investigated. The detection limit was calculated to be 0.132µgmL-1. The developed method was successfully applied for the detection and determination of CYP in various spiked samples (tomato, okra, pea, spinach, soil, and water) using the spike and recovery methods. The percent recoveries of CYP from these samples were found to be 77 ± 0.05% to 95 ± 0.12%at various levels.

Green & Sensitive pH-dependent Spectrofluorimetric Assay of Tamsulosin Hydrochloride and Tadalafil in their New Combined Formulation for Benign Prostatic Hyperplasia: Application to Spiked Human Plasma

Sensitive and green spectrofluorimetric methods were utilized for Tamsulosin Hydrochloride (TAM) and Tadalafil (TDL) assessment in bulk and their newly available combined mixture for benign prostatic hyperplasia and erectile dysfunction. The technique relies on measuring native fluorescence of TAM in 0.1 N HCl at 324 nm and TDL in 0.1 N NaOH at 348 nm due to their different fluorimetric behavior in acidic and basic media where TAM has no fluorescence in basic medium and vice versa. To achieve better regression, the spectra were derivatized allowing determination of TAM at 314 nm and TDL at 320 and 380 nm (peak to peak) by applying third and first derivative, respectively. In addition, pH-dependent “constant-wavelength synchronous” spectrofluorimetry was applied where TAM and TDL were determined at 218 nm in acidic medium and at 268 nm in basic medium, respectively. Finally, derivatizing the latter emission spectra allowed determination of TAM and TDL at 232 nm and at 262 and 278 nm (peak to peak), respectively. Acidic and basic emission spectra where scanned at λexc = 225 nm (for TAM assay) and at λexc = 247 nm (for TDL assay), respectively. Fluorescence–concentration plots were linear and the proposed methods were used for analysis of TAM and TDL combined laboratory prepared formulation. These procedures are green, sensitive and of low cost which make them suitable for quality control analysis of the two drugs. In addition, the high selectivity of the proposed methods was tested by successfully applying them for TAM and TDL assay in plasma samples.

Determination of Omeprazole, Esomeprazole and Pantoprazole by Quenching the fluorescence of Eosin Y

A non-extractive, simple and sensitive spectrofluorimetric method with good selectivity has been described for the determination of the proton pump inhibitors namely; Omeprazole, Esomeprazole magnesium and Pantoprazole sodium that are used for the treatment of peptic ulcer disease. The method is based on the quenching the fluorescence intensity of the eosin Y dye, as the result of the ion-pair complex formation of the studied drugs with the dye in the presence of acetate buffer solution of pH 3.5. The quenching of the eosin Y fluorescence intensity was measured spectrofluorimetrically at 540 nm after excitation at 352 nm. At the optimum reaction conditions, the quenching values of fluorescence (∆F) and concentrations were rectilinear over the concentration ranges of 0.5–13.0, 0.7-15 and 0.3-15 µg/mL for Omeprazole, Esomeprazole magnesium and Pantoprazole sodium respectively. The recovery % values were in the range 99.92-100.56% and relative standard deviation values range was0.430-2.521 for all the studied drugs. The method was applied successfully for determination of above drugs in their pharmaceutical formulations as capsule, tablet and injectables. The method was free from interferences of common excipients.

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