Determination of febuxostat in human plasma using ultra-performance liquid chromatography tandem mass spectrometry

Rapid Screening of Emergent Febuxostat Adulteration in Functional Foods Based on a Simulation-Inspired High-Quality Antibody

Due to the potential health risks of adulterated febuxostat in uric-acid-lowering foods, it is urgent to develop rapid detection methods. However, there are no fast analytical techniques for febuxostat yet. Herein, an efficient hapten simulation strategy was proposed to successfully produce a highly sensitive and selective monoclonal antibody toward febuxostat. Based on such a robust recognition element, easy colorimetric and ultrasensitive fluorescent lateral flow immunochromatographic immunoassays were first established, which can detect febuxostat as low as 60 μg/kg by the naked eye or 1.01 μg/kg by a commercial test strip reader with acceptable stability. Furthermore, in the recovery test and blind sample analysis, consistent results between our methods and the authorized liquid chromatography-tandem mass spectrometry method suggested the high accuracy and practicality of this work. The present work not only proposes a rational hapten design idea but also provides favorable tools for the rapid screening of febuxostat in functional foods.

Optimization and validation of a UPLC-MS/MS assay for simultaneous quantification of 2,8-dihydroxyadenine, adenine, allopurinol, oxypurinol and febuxostat in human plasma

Adenine phosphoribosyltransferase (APRT) deficiency is a rare , hereditary disorder characterized by renal excretion of 2,8-dihydroxyadenine (DHA), leading to kidney stone formation and chronic kidney disease (CKD). Treatment with a xanthine oxidoreductase inhibitor, allopurinol or febuxostat, reduces urinary DHA excretion and slows the progression of CKD. The method currently used for therapeutic monitoring of APRT deficiency lacks specificity and thus, a more reliable measurement technique is needed. In this study, an ultra-performance liquid chromatography-tandem mass spectrometry method for simultaneous quantification of DHA, adenine, allopurinol, oxypurinol and febuxostat in human plasma was optimized and validated. Plasma samples were prepared with protein precipitation using acetonitrile followed by evaporation. The chemometric approach design of experiments was implemented to optimize gradient steepness, amount of organic solvent, flow rate, column temperature, cone voltage, desolvation temperature and desolvation flow rate. Experimental screening was conducted using fractional factorial design with addition of complementary experiments at the axial points for optimization of peak area, peak resolution and peak width. The assay was validated according to the US Food and Drug Administration guidelines for bioanalytical method validation over the concentration range of 50 to 5000 ng/mL for DHA, allopurinol and febuxostat, 100 to 5000 ng/mL for adenine and 50 to 12,000 ng/mL for oxypurinol, with r2 ≥ 0.99. The analytical assay achieved acceptable performance of accuracy (-10.8 to 8.3 %) and precision (CV < 15 %). DHA, adenine, allopurinol, oxypurinol and febuxostat were stable in plasma samples after five freeze-thaw cycles at -80 °C and after storage at -80 °C for 12 months. The assay was evaluated for quantification of the five analytes in clinical plasma samples from six APRT deficiency patients and proved to be both efficient and accurate. The proposed assay will be valuable for guiding pharmacotherapy and thereby contribute to improved and more personalized care for patients with APRT deficiency.

Febuxostat alleviates Arsenic Trioxide-Induced renal injury in Rats: Insights on the crosstalk between NLRP3/TLR4, Sirt-1/NF-κB/TGF-β signaling Pathways, and miR-23b-3p, miR-181a-5b expression

Febuxostat (FBX), a xanthine oxidase inhibitor, is known to improve renal function and can show promise as a therapeutic agent for preventing drug-induced nephrotoxicity. This study aimed to explore the protective effect of FBX in preventing renal damage caused by arsenic trioxide (ATO) toxicity and uncover the underlying mechanisms. The researchers examined how FBX (10 mg/kg, orally) affected ATO-induced kidney injury (5 mg/kg, intraperitoneally) in rats. Kidney function and toxicity parameters in serum and oxidative stress biomarkers and inflammatory cytokine levels in renal tissue were measured. H&E staining was used to detect histopathological changes in the kidney. Network the molecular mechanisms of FBX in improving kidney injury were investigated using Western blotting and PCR techniques. The findings showed that FBX improved kidney function by inhibiting the pathological changes seen in H&E staining, decreasing levels of probed kidney function and toxicity measures in serum and tissue, and exhibiting antioxidant and anti-inflammatory effects. FBX decreased MDA, MPO, TNF-α, IL-1β, IL-6, COX-II, and NADPH oxidase levels, while increased GSH, GPx, SOD, and IL-10 levels. FBX also reduced the expression of NLRP3, ASC, TLR4, and micro-RNA 181a-5b while increased the expression of IKBα, Sirt-1, and micro-RNA 23b-3p, according to Western blotting and PCR results. In conclusion, FBX can play a vital role in reducing kidney injury in cases of ATO-induced nephrotoxicity, though more clinical research needs to be conducted.

Improved oral bioavailability of febuxostat by liquid self-micro emulsifying drug delivery system in capsule shells

PURPOSE

Febuxostat is a non-purine xanthine oxidase inhibitor which belongs to the BCS class II. Main aim of this study is to enhance dissolution and bioavailability of a drug by formulating a liquid self-micro emulsifying drug delivery system (SMEDDS) in different capsule shells.

METHOD

Compatability of gelatin and cellulose capsule shells was checked with different oils, surfactants and co-surfactants. Solubility studies were then carried out in selected excipients. Capryol 90, labrasol, and PEG 400 were used in a liquid SMEDDS formulation based on phase diagram and the drug loading. Further SMEDDS was characterized for zeta potential, globule size and shape, thermal stability and in vitro release. Based on the in vitro release, pharmacokinetic study was carried out using SMEDDS in gelatin capsule shells.

RESULT

The diluted SMEDDS had globule size of 157.9±1.5d.nm, zeta potential of -16.2±0.4mV and they were thermodynamically stable. The formulation was found stable for 12 months in capsule shells. When tested in different media (0.1N HCl and pH 4.5 acetate buffer), the in vitro release of newly produced formulations differed substantially from that of commercially available tablets, while the release rate in alkaline medium (pH 6.8) was comparable and the highest. According to in vivo findings in rats, a threefold increase in plasma concentration, a fourfold increase in AUC0-t, and a reduction in oral clearance increased fuxostat's oral bioavailability.

CONCLUSION

This investigation revealed that the novel liquid SMEDDS formulation sealed in capsules has considerable potential as a vehicle for enhancing the bioavailability of febuxostat.

Multi-spectroscopic assay methods for concurrent determination of recent anti-gout combination, a comparative study

Recently, Chemometric calibration methods in spectrophotometric analysis are achieving significant attention in the quality control of resolving drug mixtures and pharmaceutical formulations containing two or more drugs with overlapping spectra. The simple univariate methods have been used over the last few decades and has proven to be highly efficient and easy to apply. In this study, a comparative study was performed between some univariate and multivariate methods to determine if chemometric methods can substitute univariate methods in pharmaceutical analysis. In this study, three chemometric techniques were compared to seven univariate techniques to resolve a mixture of mefenamic acid and febuxostat in their raw materials, dosage forms and spiked human plasma. Mefenamic acid and febuxostat were used together for treatment of gout. The applied chemometric methods are partial least squares (PLS), artificial neural network (ANN) and genetic algorithm partial least squares (GA-PLS), while the used univariate methods include first derivative, second derivative, ratio spectra, derivative ratio spectra, ratio subtraction, Q-Absorbance ratio and mean centering spectrophotometric methods. The ten proposed methods were found to be green, sensitive, and rapid. They are simple and did not require any pre-separation steps. The results of both univariate and multivariate approaches were statistically compared with the reported spectrophotometric methods using student's t test and ratio variance F-test. They were also compared with each other, using one-way analysis of variance (ANOVA). These methods were assessed and validated according to ICH guidelines. The studied drugs were analyzed in their pharmaceutical dosage forms and spiked human plasma with good recoveries using the developed methods, which qualify them for routine quality control of the studied drugs.

Identification and characterization of stress degradation products of febuxostat employing ultra-performance liquid chromatography-ultraviolet/photodiode array and liquid chromatography-mass spectrometry/time-of-flight studies

RATIONALE

Febuxostat (FEB) is a xanthine oxidase inhibitor approved by the U.S. Food and Drug Administration for long-term treatment of gout and hyperuricemia. There were no reports on identification and characterization of stress degradation products of the drug.

METHODS

FEB was subjected to forced decomposition conditions such as hydrolysis (neutral, acidic, and alkaline), oxidation, photolysis, and thermal stress, per the ICH guideline Q1A(R2). The degradation products formed were subjected to ultra-performance liquid chromatography (UPLC) on a C18 Kinetex column (100 × 4.6 mm, 2.6 μm) using isocratic elution method. Detection wavelength was 317 nm. The developed method was extended to UPLC-mass spectrometry/time of flight (MS/TOF) studies to identify and characterize the degradation products.

RESULTS

The drug exhibited significant degradation under alkaline/neutral hydrolytic, alkaline/acidic photolytic, and oxidative conditions, whereas it remained stable under acid hydrolytic, neutral photolytic, and thermal conditions. In total, eight degradation products (I-VIII) were formed, which could be adequately determined from the drug using the developed UPLC method. Of the eight degradation products identified from the liquid chromatography-ultraviolet (LC-UV) chromatogram, five (III and IV and VI-VIII) could be characterized using their MS/TOF spectral data. The degradation pathway leading to the formation of the products was postulated, and this is not reported so far.

CONCLUSIONS

Forced degradation studies were conducted on FEB, and the degradation products produced were identified by their mass spectral data obtained using LC-MS studies.

Two different synchronous spectrofluorimetric approaches for simultaneous determination of febuxostat and ibuprofen

Two green, simple and sensitive synchronous spectrofluorimetric methods were developed for the first time for the simultaneous estimation of febuxostat (FEB) and ibuprofen (IBU). Method I is constant-wavelength synchronous spectrofluorimetry where FEB and IBU were recorded at 329 and 258 nm, respectively, using Δλ of 40 nm. Method II is constant-energy synchronous spectrofluorimetry using a wavenumber interval of -4000 cm-1. All measurements were carried out in a borate buffer of pH 7 and distilled water for dilution which increased the methods' greenness. The two methods were rectilinear over concentration ranges of 30.0-700.0 ng ml-1 and 0.5-9.0 µg ml-1 in the first method and 20.0-500.0 ng ml-1 and 0.1-8.0 µg ml-1 in the second method for FEB and IBU, respectively. High sensitivity was attained for the two drugs with limits of quantitations (LODs) down to 0.41 and 5.51 ng ml-1 in the first method and 0.25 and 3.32 ng ml-1 in the second method for FEB and IBU, respectively. Recovery percentages were in the range of 97.3-101.9% after extraction from spiked human plasma samples, demonstrating high bioanalytical applicability. The two methods were further applied to tablet dosage forms with good recovery results. The methods' greenness was assessed according to the analytical Eco-Scale and Green Analytical Procedure Index guidelines.

A novel quality by design approach for development and validation of a green reversed-phase HPLC method with fluorescence detection for the simultaneous determination of lesinurad, febuxostat, and diflunisal: Application to human plasma

A novel and eco-friendly reversed-phase HPLC method with fluorescence detection was developed for simultaneous estimation of two co-administered antigout drugs (lesinurad and febuxostat) with diflunisal as a nonsteroidal anti-inflammatory drug. Unlike routine methodology, the developed method was optimized using analytical quality by design approach. A full factorial design was applied to optimize the effect of variable factors on chromatographic responses. The chromatographic separation was performed using isocratic elution on the Hypersil BDS C18 column at 40°C. The mobile phase consisted of acetonitrile:potassium phosphate buffer (30.0 mM; pH 5.5, 32.2:67.8% v/v) pumped at a flow rate of 1.0 mL/min and injection volume of 20.0 μL was employed. The proposed method was able to separate the ternary mixture in <10 min. The calibration curves of diflunisal, lesinurad, and febuxostat were linear over concentration ranges of 50.0-500.0, 50.0-700.0, and 20.0-700.0 ng/mL, respectively. Recovery percentages ranging from 98.1 to 101.3% with % relative standard deviation of <2% were obtained upon spiking to human plasma samples, indicating high bioanalytical applicability. Furthermore, the method was found to be excellent green when it was assessed according to Green Analytical Procedure Index and analytical Eco-Scale guidelines.

Micelle-Enhanced conventional and synchronous spectrofluorimetric methods for the simultaneous determination of lesinurad and febuxostat: Application to human plasma

A simple synchronous spectrofluorimetric method was developed for simultaneous determination of lesinurad and febuxostat. The investigated drugs were measured at 294 and 329 nm, respectively in the presence of each other without interference at Δλ of 50 nm (Method I). The different experimental parameters affecting the fluorescence intensities were carefully studied and optimized. The maximum synchronous fluorescence intensities were obtained at pH 6.5 using borate buffer and distilled water was used as a diluting solvent. Excellent linearity ranges were obtained using 20.0-500.0 ng mL^-1 and 1.0-80.0 ng mL^-1 for lesinurad and febuxostat, respectively. The method exhibited high sensitivity with detection limits down to 4.0 ng mL^-1 and 0.01 ng mL^-1 and quantitation limits down to 12.12 ng mL^-1 and 0.02 ng mL^-1, respectively. Recovery percentages ranged from 97.68 to 103.37% were obtained upon spiking of human plasma samples, indicating high bioanalytical applicability. Concerning Method II, methanolic solution of lesinurad was measured spectroflourimetrically with λ_excitation at 290 nm and λ_emission at 341 nm with high sensitivity using borate buffer of pH 6.5 and methanol as a diluting solvent. A considerable enhancement of the fluorescence intensity was achieved by using 1.0% w/v cetremide as a micellar system. The method was rectilinear over the concentration range of 3.0-80.0 ng mL^-1 with detection and quantitation limits down to 0.47 and 1.42 ng mL^-1, respectively. The developed method was efficiently applied for the estimation of the cited drug in spiked human plasma with high recovery percentages (98.58-101.64%). The methods were validated according to the ICH guidelines and further applied to commercial tablets with good results.

Development of LC-MS/MS determination method and backpropagation artificial neural networks pharmacokinetic model of febuxostat in healthy subjects

WHAT IS KNOWN AND OBJECTIVE

Febuxostat is a well-known drug for treating hyperuricemia and gout. The published methods for determination of febuxostat in human plasma might be unsuitable for high-throughput determination and widespread application. We need to develop a highly selective, sensitive and rapid liquid chromatography-tandem mass spectrometry method.

METHODS

The chromatographic separation was achieved on a Hypersil Gold-C18 (2.1 mm × 100 mm, 1.9 μm) column with mobile phase A (Water containing 0.1% formic acid) and mobile phase B (acetonitrile containing 0.1% formic acid). Multiple reaction monitoring (MRM) mode was used for quantification using target ions at m/z 315.3 → m/z 271.3 for febuxostat and m/z 324.3 → m/z 280.3 for Febuxostat-d₉ (IS). A backpropagation artificial neural network (BPANN) pharmacokinetic model was constructed by the data of bioequivalence study.

RESULTS AND DISCUSSION

After the LC-MS/MS method validated, it was successfully applied to the bioequivalence study of 30 human volunteers under fed condition. The predicted concentrations generated by BPANN model had a high correlation coefficient with experimental values.

WHAT IS NEW AND CONCLUSION

A sensitive LC-MS/MS method had been developed and validated for determination of febuxostat in healthy subjects under fed condition, and a BPANN model was developed that can be used to predict the plasma concentration of febuxostat.

Formulation and Characterization of Nanosized Ethosomal Formulations of Antigout Model Drug (Febuxostat) Prepared by Cold Method: In Vitro/Ex Vivo and In Vivo Assessment

Febuxostat (FXT) is a xanthine oxidase (XO) drug which indicated for the treatment of gout. FXT loaded nanosized ethosomes were prepared using cold method with varied concentrations of ethyl alcohol and soya lecithin (SL). The prepared ethosomes were characterized by size, entrapment efficiency (DEE), FT-IR, in vitro release, kinetic studies of in vitro release profile, in vitro skin permeation and deposition, and stability study. The selected ethosomal formulation was incorporated in HPMC gel and characterized for drug content, ex vivo diffusion study through rat skin, and in vivo study and determination of pharmacokinetic parameters using HPLC technique. The results of size analysis showed that minimum size was 124.2 ± 16.77 nm with PDI values between 0.2 and 0.6. The zeta potential was from - 43.5 ± 3.0 to - 20.6 ± 1.42 mV. DEE ranged from 48 to 86%. The results of in vitro skin permeation showed that the amount FXT permeated ranged from 43.33 ± 5.3 to 82.14 ± 5.8%, flux ranged from 14.85 to 28.02. The results of ex vivo study showed that the amount of FXT permeated from unprocessed FXT gel was 49.42 ± 3.29% which was lesser than from FXT ethosomal gel. The results of in vivo study showed that C_max and t_max were significantly different and higher for transdermal administration of FXT than oral administration. The developed FXT nanosized selected ethosome-based transdermal drug delivery gel system would provide a promising method for better management of gout.

A novel HPLC-DAD method for simultaneous determination of febuxostat and diclofenac in biological samples: pharmacokinetic outcomes

Aim: To develop a simple HPLC-DAD method for simultaneous determination of febuxostat (FEB) and diclofenac (DIC) in biological samples to assess pharmacokinetic outcomes of their coadministration. Methodology & results: Sample preparation was performed by liquid–liquid extraction. Drugs analysis was done on C18 column using methanol-formic acid pH 2.1 (76:24, v/v) as mobile phase and time-programmed UV detection. Lower limits of quantitation for FEB and DIC were 10 and 20 ng/ml, respectively. Baseline pharmacokinetics were similar to published data on either drug alone. Coadministration led to more than twofold increase in FEB Cmax and AUC together with a reduced hepatic uptake in rats. Conclusion: DIC interfered with initial distribution and terminal clearance of FEB potentially due to reduced FEB hepatic uptake.

Innovative HPTLC method with fluorescence detection for assessment of febuxostat–montelukast combination and study of their protective effects against gouty arthritis

This study was designed to evaluate the potential protective effects of montelukast, febuxostat and their combination on a model of acute gouty arthritis, and to establish a HPTLC method for determination of both drugs simultaneously.

Salting-Out Assisted Liquid-Liquid Extraction for Quantification of Febuxostat in Plasma Using RP-HPLC and Its Pharmacokinetic Application

A rapid and sensitive reversed-phase high-performance liquid chromatography (HPLC) method using novel salting-out assisted liquid-liquid extraction technique has been developed for the quantitative determination of febuxostat (FEB), used for the treatment of gout, in rat plasma. The method was validated according to US FDA guideline. Separation was achieved using a Phenomenex Luna-C₁₈ (250 × 4.60 mm, 5 µm) column and mobile phase composed of potassium dihydrogen orthophosphate buffer 25 mM, adjusted to pH 6.8 with triethylamine:methanol in a ratio of 35:65 (v/v) showing retention time 5.56 and 8.86 min for FEB and internal standard, respectively. The optimal salting-out parameters; 1 mL of acetonitrile and 200 µL of 2 M ammonium acetate salt showed extraction recovery >90% for FEB from plasma. This extraction procedure afforded clear samples resulting in convenient and cost-saving procedure and showed good linear relationship (r > 0.9997) between peak area ratio and concentration from 0.3 to 20 µg/mL. The results of pharmacokinetic study showed that absorption profile of spherical agglomerate of FEB compared to marketed formulation was higher indicating greater systemic absorption. In conclusion, the developed SALLE-HPLC method with simple ultraviolet detection offered a number of advantages including good quantitative ability, wide linear range, high recovery, short analysis time as well as low cost.

Specific and highly sensitive spectrofluorimetric method for determination of febuxostat in its tablets and real human plasma. Application to stability studies

A simple, rapid, specific and highly sensitive spectrofluorimetric method has been developed for determination of febuxostat (FEB) in its tablets and real human plasma.

Method Development and Validation for Determination of Febuxostat from Spiked Human Plasma Using RP-HPLC with UV Detection

A rapid, simple, selective, and specific reverse phase high performance liquid chromatography (RP-HPLC) method with UV detection (315 nm) was developed and validated for estimation of febuxostat from spiked human plasma. The analyte and internal standard (diclofenac) were extracted using LLE with diethyl ether. The chromatographic separation was performed on Shodex C-18-4E (5 μm; 250×4.6 mm) with a mobile phase comprised of methanol : acetate buffer pH 4, 20 mM (90 : 10 v/v), at a flow rate of 1 mL/min. Febuxostat was well resolved from plasma constituents and internal standard. The calibration curve was linear in the range of 250–8000 ng/mL. The heteroscedasticity was minimized by using weighted least square regression with weighing factor of 1/x. The intraday and interday %RSD was less than 15. Results of recovery studies prove the extraction efficiency. Stability data indicated that febuxostat was stable in plasma after three freeze thaw cycles and upon storage at −20°C for 30 days.

Bioequivalance and pharmacokinetic study of febuxostat in human plasma by using LC-MS/MS with liquid liquid extraction method

A bioequivalence study was proved of generic Febuxostat 80 mg tablets (T) in healthy volunteers.For this purpose, Authors developed a simple, sensitive, selective, rapid, rugged and reproducible liquid chromatography-tandem mass spectrometry method for the quantification of Febuxostat (FB) in human plasma using Febuxostat D7 (FBD7) as an internal standard (IS) was used. Chromatographic separation was performed on Ascentis Express C18 (50x4.6 mm, 3.5 μ) column. Mobile phase composed of 10 mM Ammonium formate: Acetonitrile (20:80 v/v), with 0.8 mL/min flow-rate. Drug and IS were extracted by Liquid- liquid extraction. FB and FBD7 were detected with proton adducts at m/z 317.1→261.1 and 324.2→262.1 in multiple reaction monitoring (MRM) positive mode respectively. The method was validated with the correlation coefficients of (r(2)) ≥ 0.9850 over a linear concentration range of 1.00-8000.00 ng/mL. This method demonstrated intra and inter-day precision within 2.64 to 3.88 and 2.76 to 8.44% and accuracy within 97.33 to 99.05 and 100.30 to 103.19% for FB. This method is successfully applied in the Bioequivalence study of 9 human volunteers.