Development of high performance liquid chromatography-ultraviolet detection method for screening mebendazole, clorsulon, diaveridine, and tolfenamic acid in animal-based food samples

Identification of major degradation products of Clorsulon drug substance including its degradation pathways by high resolution mass spectrometry and NMR

Clorsulon is an effective anthelmintic drug substance extensively used in the treatment of parasitic infestations in both cattle and sheep. An in-depth investigation of Clorsulon's degradation products (DPs) was carried out through forced degradation study to comprehend its degradation path. A total of eight degradation products were separated under various stress degradation conditions. Structural elucidation of these DPs was conducted using ultra-high performance liquid chromatography-high resolution mass spectrometry (UHPLC-HRMS), and their fragmentation patterns were compared to that of the parent compound. Adequate amount of DP-4 was isolated and purified by semi-preparative high-performance liquid chromatography (HPLC) methods. Subsequently, it was examined in detail using both 1D and 2D NMR (nuclear magnetic resonance spectroscopy). Most probable mechanistic pathways for the formation of degradation products under various stress degradation conditions were proposed to better understand the degradation profile. Based on the results of the stress study, Clorsulon drug substance was found to be unstable under photolytic and oxidative conditions. Understanding Clorsulon's degradation pathway is essential for determining shelf-life prediction of the finished product, safety and efficacy assurance, and guiding the development of stable, high-quality formulations.

Determination of Clorsulon and its related substances in commercial bulk drug substance batches by a rapid ion-pair UPLC method

Clorsulon is a potent anthelmintic agent and is widely used for the treatment and control of parasites including adult liver flukes in cattle and sheep. A rapid ion-paired reversed phase ultraperformance liquid chromatography (IP-UPLC) method has been developed and validated for determination of Clorsulon and its related substances in bulk drug substance batches of Clorsulon with a short octadecyl column. Analytes were eluted by a gradient elution on a Acquity UPLC® BEH C18 column (50 mm × 2.1 mm i.d., 1.7 µm particle size). Column temperature was maintained at 55 °C and all analytes were monitored by UV detection at 268 nm. Mobile phase-A constitutes 3 mM tetrabutylammonium hydroxide in H2O and mobile phase-B constitutes acetonitrile/methanol (50/50, v/v), respectively. All analytes of interest were adequately separated within 5 min. The analytes were quantitated against an external reference standard of Clorsulon. The chemical structures of degradation products of Clorsulon were proposed based on two-dimensional UPLC-MS data. The IP-UPLC method has been successfully validated and demonstrated to be accurate, sensitive, robust, and specific.

Analysis of Tolfenamic Acid using a Simple, Rapid, and Stability-indicating Validated HPLC Method

BACKGROUND

Tolfenamic acid (TA) belongs to the fenamates class of nonsteroidal anti-inflammatory drugs. Insufficient information is available regarding the availability of a reliable and validated stability-indicating method for the assay of TA.

OBJECTIVE

A relatively simple, rapid, accurate, precise, economical, robust, and stabilityindicating RP-HPLC method has been developed to determine TA in pure and tablet dosage forms.

METHODS

The method was validated according to the ICH guideline, and parameters like linearity, range, selectivity, accuracy, precision, robustness, specificity, and solution stability were determined. TLC and FTIR spectrometry were used to ascertain the purity of TA. The specificity was determined with known impurities and after performing forced degradation, while the robustness was established by Plackett-Burman's experimental design. The mobile phase used for the analysis was acetonitrile and water (90:10, v/v) at pH 2.5. The detection of the active drug was made at 280 nm using a C18 column (tR = 4.3 min.). The method's applicability was also checked for the yellow polymorphic form of TA.

RESULTS

The results indicated that the method is highly accurate (99.39-100.80%), precise (<1.5% RSD), robust (<2% RSD), and statistically comparable to the British Pharmacopoeia method with better sensitivity and specificity.

CONCLUSION

It was observed that the stress degradation studies do not affect the method's accuracy and specificity. Hence the proposed method can be used to assay TA and its tablet dosage form.

Pharmacokinetics of mebendazole in plasma and cerebrospinal fluid following a single oral dose in healthy dogs

Novel therapies are needed for treatment of gliomas. Mebendazole previously demonstrated anti-neoplastic effects on canine glioma cell lines at in vitro mean inhibitory concentrations (IC50) of 10 ng/mL. Our study aimed to titrate the oral dose of mebendazole necessary to achieve concentrations ≥10 ng/mL in cerebrospinal fluid (CSF) of healthy dogs. We hypothesized that an oral dose up to 200 mg/kg would be necessary. Phase one was a dose titration study using a total of 6 mixed breed dogs that described dose vs. plasma concentrations for 72 h after single oral dosing of either 50 mg/kg (n = 2), 100 mg/kg (n = 2), or 200 mg/kg (n = 2). Based on phase one, phase two dogs (total of 9) received 100 mg/kg (n = 4) or 200 mg/kg (n = 5) orally and blood samples were collected intermittently for 60 h with CSF samples collected intermittently for 24 h. Mebendazole was quantitated in plasma and CSF using high performance liquid chromatography. Median peak plasma concentrations (Cmax) were reached at 7 ± 2 h (100 mg/kg) of 220 ng/mL (81, 283) and at 15 ± 4 h (200 mg/kg) of 147 ng/ml (112, 298). The respective area under the curve (AUC: ng/ml/h) reported as a median was 2,119 (1,876, 3,288) vs. 3,115 (1,559, 4,972). Median plasma concentrations (ng/ml) for 100 vs. 200 mg/kg were 47 (32, 52) vs. 65 (35, 104), respectively. For CSF, the median value for Cmax (at 100 mg/kg vs. 200 mg/kg) was 8 (2, 28) vs. 21 (12, 27) and AUC was 87 (22, 157) vs. 345 (92, 372), respectively. Relative bioavailability in CSF vs. plasma was 4 to 10%. Although several animals demonstrated clinical signs indicative of gastrointestinal upset [i.e., vomiting (n = 2), diarrhea (n = 2), or both (n = 1)], these events were not considered serious. The in vitro IC50 for gliomas can be reached in CSF at 100 mg/kg (n = 1), however a 200 mg/kg dose yielded more consistent concentrations.

Simultaneous Determination of Levamisole, Mebendazole, and the Two Metabolite Residues of Mebendazole in Poultry Eggs by High-Performance Liquid Chromatography–Tandem Mass Spectrometry

The quantitative determination of levamisole (LMS), mebendazole (MBZ), and the two metabolites of MBZ, 5-hydroxymebendazole (HMBZ) and 2-amino-5-benzoylbenzimidazole (AMBZ), in poultry eggs (hen, duck, and goose) was achieved with high-performance liquid chromatography–tandem triple quadrupole mass spectrometry (HPLC–MS/MS). Samples were pretreated by liquid–liquid extraction and solid-phase extraction (LLE–SPE) to extract the target compounds, and an Oasis MCX SPE column was used for purification. Determination was performed on an Xbridge C18 column with 0.1% formic acid aqueous solution and acetonitrile as mobile phases. LMS, MBZ, HMBZ, and AMBZ were detected in a triple-quadrupole mass spectrometer with ESI in positive mode and quantified with an external standard. In blank eggs, the target analyte concentrations were within the limits of quantification (LOQs)—25 μg/kg (LMS) and 150 μg/kg (MBZ, HMBZ, and AMBZ)—and the matrix-matched calibration curves had good linearity (R2 ≥ 0.9990). In the same concentration range, the average recoveries of the target analytes were 85.98–97.38% (n = 6); the relative standard deviation (RSD), intraday RSD, and interday RSD ranged from 2.06 to 4.22%, 1.40 to 5.85%, and 2.34 to 6.32%, respectively. The limits of detection (LODs) ranged from 0.03 to 0.33 µg/kg, and the LOQs ranged from 0.08 to 1.00 µg/kg. Experimental verification showed that the HPLC–MS/MS method exhibited high specificity and sensitivity for quantitative analyses of egg samples. This study provides a rapid, efficient, and sensitive method for the simultaneous detection of LMS, MBZ, HMBZ, and AMBZ residues in foods of animal origin.

Metabolite Identification and Pharmacokinetic Behavior of Diaveridine in the Plasma of Pigs and Chickens Based on Radioactive Tracing Coupled With LC/MS-IT-TOF Assay

Diaveridine (DVD) is widely used for the prevention and treatment of coccidiosis and leucocytozoonosis infections in food-producing animals. To gain a better understanding of DVD metabolism and pharmacokinetics in healthy Landrace/Doric Cross castrated male pigs and both female and male Cobb 500 broiler chickens, a method involving radioactive tracing coupled with LC/MS-IT-TOF was developed for the identification and quantitation of DVD and its metabolites in pig and chicken plasma, and then was applied to investigate DVD pharmacokinetics. A simple MCX solid phase extraction procedure was adopted for sample preparation. After a single oral administration of 3H-DVD (10 mg/kg BW), three radioactive compounds (D0: DVD; D1: 3'-desmethyl-DVD; and D2: monoglucuronide of 3'-desmethyl-DVD) were identified in pig plasma, while only two radioactive compounds (D0 and D2) were identified in chicken plasma. In both species, the C max values for all detected compounds were reached at 2 h after dosing. The C max order was D2 (1.38 μg/ml) > D0 (0.49 μg/ml) > D1 (0.24 μg/ml) in pigs and D0 (1.55 μg/ml) > D2 (0.27 μg/ml) in chickens. The longer t 1/2 (elimination half-life) of D0 contributed to the slow elimination of DVD-related compounds. The t 1/2β of D0 in pigs (66.41 h) was significantly longer than that in chickens (48.30 h), but the t 1/2 of total DVD-related metabolites in pigs (42.86 h) was lower than that in chickens (56.11 h). These findings suggested that the metabolism and pharmacokinetics of DVD in pigs and chickens were significantly different, and that this would affect its effectiveness, toxicology, and food safety in these animals.

Simultaneous determination of ivermectin, clorsulon and their related substances in an injectable finished product by a stability-indicating RP-HPLC method

A reversed-phase high performance liquid chromatography (RP-HPLC) method has been developed for the determination of ivermectin and clorsulon, including the identification and estimation of their related impurities in an ivermectin and clorsulon injectable finished product. Chromatographic separation was achieved using a gradient elution on a Supelco Ascentis® Express C18 column (150 mm × 4.6 mm i.d., 5 µm particle size) maintained at 55 °C. Mobile phase-A is composed of water and mobile phase-B is composed of acetonitrile/methanol (65/35, v/v). Analytes were monitored by UV detection at 245 nm. The stability-indicating capability of this method has been demonstrated by the adequate separation of all the process related impurities and degradation products of ivermectin and clorsulon from the stress degraded samples of the injectable product. This method was also successfully validated as per the current ICH guidelines with respect to specificity, linearity (R²> 0.999), limit of detection (0.3 μg/mL), limit of quantitation (1.0 μg/mL), accuracy, precision, and robustness for both APIs. This proposed method can significantly benefit the end-users in QC laboratories with laboratory efficiency and throughput during routine analysis and stability monitoring of the injectable product.

Screening and Analysis of Multiclass Veterinary Drug Residues in Animal Source Foods using UPLC-Q-Exactive Orbitrap/MS

A rapid, simple, and sensitive method of detecting veterinary drug residues in animal food sources, including poultry and pork, was developed and validated. The method was optimized for over 155 veterinary drugs of 21 different classes. Sample pretreatment included a simple solid-liquid extraction step with 0.2% formic acid-acetonitrile-water and a purification step with a PRiME HLB (hydrophile-lipophile balance) solid-phase extraction cartridge. Data were collected using ultra-high-performance liquid chromatography coupled to Quadrupole-Exactive Orbitrap mass spectrometry. The limits of detection of 155 veterinary drugs ranged from 0.1 µg/kg to 10 µg/kg. The recovery rates were between 79.2 and 118.5 % in all matrices studied, with relative standard deviation values less than 15% (n = 6). The evaluated method allows the reliable screening, quantification, and identification of 155 veterinary drug residues in animal source food and has been successfully applied in authentic samples.

A Thorough HPLC Assay of Quaternary Veterinary Formulation coupled with Environmental Assessment Tool

A new and accurate reversed phase HPLC method with UV detection has been established for any veterinarian analyst for simultaneous determination of a veterinary quaternary mixture of sulphadimidine sodium (SDS), sulphaquinoxaline sodium (SQS), diaveridine (DVD) and vitamin K3 (VTK3) in their formulation. The stationary phase was SEA C18 column (250 × 4.6 mm i.d., 5 μm particle size) at 25°C with an isocratic mode, using a mobile phase containing a mixture of methanol:acetonitrile:distilled water in the ratio of (20:20:60, by volume). The flow rate was 0.8 mL min-1, and UV detection was performed at 230 nm. The HPLC assay was coupled with Environmental Assessment Tool (EAT), which represents a simple and proficient approach for profiling the greenness of the method. This takes into consideration the environmental, health and safety issues for all solvents that involved in the chromatographic method and calculates a total score that can be used for comparison of the greenness of different methods. The method was found to be linear over (0.5-30) μg/mL for all cited drugs with mean percentage recoveries (99.56 ± 1.141) for VTK3, (99.56 ± 1.056) for DVD, (99.62 ± 1.482) for SDS and (99.52 ± 1.205) for SQS. The results were statistically compared with those of the official and reported methods; using Student's t-test and F-test, showing no significant difference with respect to accuracy. Specificity of the applied method was assessed by analyzing the laboratory-prepared mixtures. The developed method was validated according to ICH guidelines. The proposed methodology can be applied for rapid routine assay of this combination.

Comprehensive comparative study of eco-friendly Univariate and multivariate methodological approaches on processing multi-component formulation quality

This study presents comprehensive comparative study of different eco-friendly spectrophotometric approaches without any sample treatment on processing quaternary mixture of sulphadimidine sodium (SDS), sulphaquinoxaline sodium (SQS), diaveridine (DVD) and vitamin K₃ (VTK₃). The different univariate complementary resolutions according to the response used for the assay of the cited drugs after applying the processing steps were implemented using successive ratio subtraction coupled with constant multiplication (SRS-CM), absorbance subtraction (AS) and amplitude modulation (AM). On the other hand, multivariate spectrophotometric models were developed and validated for simultaneous determination of the cited mixture. Resolution was accomplished by using two multivariate calibration greener models, including principal component regression (PCR) and partial least-squares (PLS). The proposed approaches are considered environmentally friendly since they use only water as reagent, which is cheap and safe for the operator. The calibration graphs are linear over the range of (4.0-13.0) μg/mL for (SDS), (1.0-10.0) μg/mL for (SQS), (1.0-11.0) μg/mL for (DVD) and (1.0-8.0) μg/mL for (VTK₃). Specificity of the applied procedures was assessed by analyzing the laboratory-prepared mixtures and their combined dosage form. The outcomes of the developed methods were statistically compared with those of the official and reported methods; using Student's t-test and F-test, showing no significant difference. The proposed methodologies can be used for the routine analysis of the cited drugs in quality control laboratories.

Use of Micellar Liquid Chromatography to Determine Mebendazole in Dairy Products and Breeding Waste from Bovine Animals

Mebendazole is an anthelmintic drug used in cattle production. However, residues may occur in produced food and in excretions, jeopardizing population health. A method based on micellar liquid chromatography (MLC) was developed to determine mebendazole in dairy products (milk, cheese, butter, and curd) and nitrogenous waste (urine and dung) from bovine animals. Sample treatment was expedited to simple dilution or solid-to-liquid extraction, followed by filtration and direct injection of the obtained solution. The analyte was resolved from matrix compounds in less than 8 min, using a C18 column and a mobile phase made up of 0.15 M sodium dodecyl sulfate (SDS)–6% 1-pentanol phosphate buffered at pH 7, and running at 1 mL/min under isocratic mode. Detection was performed by absorbance at 292 nm. The procedure was validated according to the guidelines of the EU Commission Decision 2002/657/EC in terms of: specificity, method calibration range (from the limit of quantification to 25–50 ppm), sensitivity (limit of detection 0.1–0.2 ppm; limit of quantification, 0.3–0.6 ppm), trueness (92.5–102.3%), precision (<7.5%, expressed at RSD), robustness, and stability. The method is reliable, sensitive, easy-to-handle, eco-friendly, safe, inexpensive, and provides a high sample-throughput. Therefore, it is useful for routine analysis as a screening or quantification method in a laboratory for drug-residue control.

Tolfenamic Acid

Tolfenamic acid (TA) is a nonsteroidal antiinflammatory drug and belongs to the group of fenamates. It is used as a potent pain reliever in the treatment of acute migraine attacks, and disorders like dysmenorrhea, rheumatoid, and osteoarthritis. TA has shown excellent in vitro antibacterial activity against certain ATCC strains of bacteria when complexed with bismuth(III). It has also been reported to block pathological processes associated with Alzheimer's disease. In the recent past, TA has also been used as a novel anticancer agent for the treatment of various cancers. In view of the clinical importance of TA, a comprehensive review of the physical and pharmaceutical properties and details of the various analytical methods used for the assay of the drug in pharmaceutical and biological systems has been made. The methods reviewed include identification tests and titrimetric, spectrophotometric, chromatographic, electrochemical, thermal, microscopic, enzymatic, and solid-state techniques. Along with the analytical profile, the stability and degradation of TA, its pharmacology and pharmacokinetics, dosage forms and dose, adverse effects and toxicity, and interactions have been discussed.

Simultaneous detection of flumethasone, dl-methylephedrine, and 2-hydroxy-4,6-dimethylpyrimidine in porcine muscle and pasteurized cow milk using liquid chromatography coupled with triple-quadrupole mass spectrometry

A simple analytical method based on liquid chromatography coupled with triple-quadrupole mass spectrometry was developed for detection of the veterinary drugs flumethasone, dl-methylephedrine, and 2-hydroxy-4,6-dimethylpyrimidine in porcine muscle and pasteurized cow milk. The target drugs were extracted from samples using 10mM ammonium formate in acetonitrile followed by clean-up with n-hexane and primary secondary amine sorbent (PSA). The analytes were separated on an XBridge™ hydrophilic interaction liquid chromatography (HILIC) column using 10mM ammonium formate in ultrapure water and acetonitrile. Good linearity was achieved over the tested concentrations in matrix-fortified calibrations with correlation coefficients (R(2))≥0.9686. Recovery at two spiking levels ranged between 73.62-112.70% with intra- and inter-day precisions of ≤20.33%. The limits of quantification ranged from 2-10ng/g in porcine muscle and pasteurized cow milk. A survey of market samples showed that none of them contained any of the target analytes. Liquid-liquid purification using n-hexane in combination with PSA efficiently removed the interferences during porcine and milk sample extraction. The developed method is sensitive and reliable for detection of the three target drugs in a single chromatographic run. Furthermore, it exhibits high selectivity and low quantification limits for animal-derived food products destined for human consumption.

Validation of a UV Spectrometric Method for the Assay of Tolfenamic Acid in Organic Solvents

The present study has been carried out to validate a UV spectrometric method for the assay of tolfenamic acid (TA) in organic solvents. TA is insoluble in water; therefore, a total of thirteen commonly used organic solvents have been selected in which the drug is soluble. Fresh stock solutions of TA in each solvent in a concentration of 1 × 10⁻⁴M (2.62 mg%) were prepared for the assay. The method has been validated according to the guideline of International Conference on Harmonization and parameters like linearity, range, accuracy, precision, sensitivity, and robustness have been studied. Although the method was found to be efficient for the determination of TA in all solvents on the basis of statistical data 1-octanol, followed by ethanol and methanol, was found to be comparatively better than the other studied solvents. No change in the stock solution stability of TA has been observed in each solvent for 24 hours stored either at room (25 ± 1°C) or at refrigerated temperature (2–8°C). A shift in the absorption maxima has been observed for TA in various solvents indicating drug-solvent interactions. The studied method is simple, rapid, economical, accurate, and precise for the assay of TA in different organic solvents.