Simultaneous determination of colchicine and febuxostat in rat plasma: Application in a rat pharmacokinetic study

Evaluation of the pharmacokinetics, chylomicron inhibition, and toxicity of colchicine in rats given low doses

Colchicine (COL) is known for its ability to inhibit the formation of intestinal chylomicrons and has been utilized as a non-surgical tool to explore drug absorption via the intestinal lymphatics. However, there is limited understanding of its pharmacokinetics and its relationship to effect and toxicity with the doses used. This study aimed to provide comprehensive COL pharmacokinetic data and correlate it with the lymphatic-blocking and toxicological effects of low-doses. Male Sprague-Dawley rats with jugular-vein cannulation (JVC) received 0.1 to 0.5 mg/kg COL via oral, 0.25 mg/kg intraperitoneal, and 0.1 mg/kg intravenous routes, followed by blood and urine sampling for LC-MS/MS analysis. Effects on lipid absorption were assessed in another eight JVC rats receiving peanut oil with and without COL, followed by blood pharmacokinetic and plasma biochemistry analysis. The results revealed that COL exhibited high total body clearance and volume of distribution, with low oral bioavailability (<8%). About 20 % was recovered in the urine after parenteral dosing. Modest but significant reductions in cholesterol absorption was observed after oral doses of 0.5 mg/kg, accompanied by signs of inflammation and increased liver enzymes persisting for a week. The effect of COL on triglycerides formation was not significant. Despite its use as a non-surgical tool in rats to investigate drug absorption via the lymphatic pathway, COL demonstrated increased levels of liver function enzymes, emphasizing the need for caution and dose optimization in its utilization.

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.

In-syringe dispersive solid phase filter extraction cleanup followed by liquid chromatography-triple quadrupole mass spectrometry for fast determination of colchicine in plasma/urine

As an effective treatment for acute gouty arthritis and cardiovascular disease, colchicine is also a toxic alkaloid and may cause poisoning or even death in overdose. The study of colchicine elimination and the diagnosis of poisoning etiology need the rapid and accurate quantitative analysis method in biological matrix. An analytical method was developed for colchicine in plasma and urine by in-syringe dispersive solid phase extraction (DSPE) followed by liquid chromatography-triple quadrupole mass spectrometry (LC-MS/MS). Sample extraction and protein precipitation were proceeded with acetonitrile. The extract was cleaned by in-syringe DSPE. An XBridge™ BEH C₁₈ column（100 mm × 2.1 mm, 2.5 µm）was used to separate colchicine by gradient elution with mobile phase of 0.01% (v/v) ammonia-methanol. The amount and filling sequence of magnesium sulfate (MgSO₄) and primary secondary amine (PSA) suitable for in-syringe DSPE were studied. Scopolamine was screened as the quantitative internal standard (IS) for colchicine analysis according to the consistency of recovery rate, chromatographic retention time and matrix effects. The limits of detection for colchicine in plasma and urine were both 0.06 ng mL^-1 and the limits of quantitation were both 0.2 ng mL^-1. The linear range was 0.04 - 20 ng mL^-1 (Equivalent to 0.2-100 ng mL^-1 in plasma or urine) with a correlation coefficient r > 0.999. By IS calibration, the average recoveries at three spiking levels in plasma and urine were 95.3-102.68% and 93.9-94.8% with the relative standard deviations (RSDs) of 2.9-5.7% and 2.3-3.4%, respectively. The matrix effects, stability, dilution effects and carryover for determination of colchicine in plasma and urine were also evaluated. The elimination of colchicine within 72-384 h post-ingestion was studied for a poisoning patient with the doses of 1 mg d^-1 for 39 days and then 3 mg d^-1 for 15 days).

Development, validation, and clinical application of a rapid UPLC-MS/MS method for detection of colchicine in human whole blood and urine

A rapid, simple, and economical method has been developed to determine colchicine in both human whole blood and urine using UPLC-MS/MS. Colchicine and isotope-labeled internal standard were extracted from the matrix by liquid-liquid extraction with saturated borax and ethyl acetate, and separated by a reversed-phase chromatography C18 column. Gradient elution was carried out using acetonitrile and water spiked with 0.01% formic acid. Multiple reaction monitoring was performed at positive ion mode. The quantitative transitions were m/z 400.27 → 310.28 for colchicine and m/z 406.16 → 313.18 for colchicine-D6. The method has good linearity in the range of 0.5-200 ng/mL for blood and 2-2000 ng/mL for urine. The sensitivity, accuracy, and matrix effect were all in line with the guidelines of Food and Drug Administration and European Medicines Agency. The extraction recovery was above 63.94%. The samples were stable under various storage conditions. Six deuterium-substituted isotopic internal standard was used to demonstrate a different mode of colchicine cleavage from the existing literature. This method has been successfully used in the diagnosis of patients with colchicine poisoning. Blood is recommended as the optimal sample compared with urine.

Smart spectrophotometric methods for stability assessment of two co-formulated antigout drugs

Simple, sensitive and accurate stability indicating spectrophotometric methods have been developed for the simultaneous determination of probenecid, colchicine as well as colchicine degradation product in their ternary mixture. Probenecid was firstly assayed using the double divisor ratio spectra derivative method. On the other hand, three spectrophotometric methods, namely: ratio difference, derivative ratio and mean centering of ratio spectra, have been suggested for the simultaneous quantification of colchicine and its degradation product. The obtained calibration curves were linear at 2.5-30.0 μg/mL, 0.5-25.0 μg/mL and 1.0-13.0 μg/mL for probenecid, colchicine and colchicine degradation product, respectively. The investigated methods were validated in accordance with the International Council for Harmonisation guidelines and were effectively used for quantification of probenecid and colchicine in their bulk powders and combined pharmaceutical dosage form.

Simultaneous determination of febuxostat and montelukast in human plasma using fabric phase sorptive extraction and high performance liquid chromatography-fluorimetric detection

In the present work, a new sensitive and selective high-performance liquid chromatography-fluorimetric detection (HPLC-FLD) method was developed and validated to quantify febuxostat (FBX) and montelukast (MON) in human plasma. The developed procedure was successfully applied to a study aimed at evaluating the pharmacokinetic profiles of febuxostat and montelukast in human plasma. A sol-gel poly (caprolactone)-block-poly(dimethylsiloxane)-block-poly(caprolactone) (sol-gel PCAP-PDMS-PCAP) extraction sorbent coated fabric phase sorptive extraction membrane was used in the extraction process. The entire chromatographic analysis was performed with isocratic elution of the composition of the mobile phase (acetonitrile:water, 60:40, v:v, 0.032% glacial acetic acid) on the C18 column. The flow rate is varied during the analysis, particularly from 0.5 mL min^-1 at the start and linearly increased to 1.5 mL min^-1 in 7 min. The detection and quantification of the analytes was carried out by means of a fluorimetric detector at 320 nm and 350 nm as absorption wavelengths and at 380 and 400 nm as emission wavelengths for FBX and MON, respectively. The calibration curves demonstrated linearity in the range 0.3-10 ng mL^-1 and 5-100 ng mL^-1 for FBX and MON, respectively, while the LOD and LOQ values were 0.1 and 0.3 ng mL^-1 for FBX and 1.5 and 5 ng mL^-1 for MON. Intraday and interday RSD% values were found lower than 5.79%. As reported, the method was applied to real plasma samples obtained from a volunteer who was co-administered both the drugs. Pharmacokinetic data reveal that the concentration of both the drugs reaches the plateau approximately at the same time, but exhibits an elimination phase at different rates. This study demonstrated the usefulness of the new method and its applicability in therapeutic drug monitoring (TDM).

Liquid Chromatography Tandem Mass Spectrometric Analytical Method for Study of Colchicine in Rats Given Low Doses

A selective and sensitive assay was developed for colchicine in rat specimens. Colchicine and its deuterated analog (as internal standard, IS) were extracted from rat specimens (minimal 0.1 mL plasma, whole blood, or urine) using liquid-liquid extraction with n-hexane:dichloromethane:isopropanol. The mobile phase (formic acid: ammonium acetate: methanol) was pumped with uniform flow through an octadecylsilane analytical column. Detection was carried out by electrospray positive ionization in the multiple-reaction monitoring mode. The assay (total run time <3 min) had excellent linearity over a wide (400–800-fold) concentration range. The mean absolute recovery was >96.8%. The intra- and inter-day coefficients of variation were ˂15%, with lower limits of quantitation of 0.5 ng/mL in 0.1 mL of rat plasma. The method also provided the same lower limits of quantitation in urine and whole blood with 0.1 mL volumes, and 0.1 ng/mL using 0.5 mL of rat plasma. The blood-to-plasma ratio was >1. Rats had measurable colchicine blood concentrations for at least 24 h after intravenous doses of 0.1 mg/kg. The method possessed suitable measures of sensitivity and selectivity for detecting colchicine in several specimen types in rats given low doses.

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.

Stability-Indicating Chromatographic Methods for the Simultaneous Determination of Probenecid and Colchicine in Their Combined Tablet

Two stability-indicating chromatographic methods have been established and validated for concurrent determination of probenecid (PRO), colchicine (COL) along with the degradation product of colchicine (COL deg). PRO and COL were exposed to a stress stability study, which includes acidic, alkaline, oxidative, photolytic and thermal degradations. Chromatographic methods included the use of thin layer chromatography (TLC-densitometry) and high performance liquid chromatography (HPLC). In the first method, separation was achieved by using aluminum TLC plates that were precoated with silica gel G.F254 as the stationary phase and ethyl acetate-methanol-33%ammonia (8:1:1, by volume) as a mobile phase. The obtained chromatograms were scanned at 254 nm. The second method was based on HPLC using a RP- C18 column with isocratic elution. Good separation was obtained through a mobile phase comprised of phosphate buffer pH 5-acetonitrile (70:30, v/v) at a flow rate of 1.0 mL min-1 and ultraviolet detection at 254 nm. Different parameters affecting efficiency of the two methods were studied accurately for optimum separation of the three cited components. The suggested methods were validated according to the International Conference on Harmonization (ICH) guidelines and were applied for bulk powder and commercial tablets.

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.