Albendazole Sulfone Research Articles

Understanding Drug Exposure and Trichuris trichiura Cure Rates: A Pharmacometric Approach for Albendazole-Ivermectin Co-medication in Tanzania and Côte d'Ivoire.

Trichuriasis caused by the human whipworm Trichuris trichiura poses a significant public health concern. Albendazole-ivermectin co-medication is currently the most effective treatment. Studies conducted in Tanzania and Côte d'Ivoire unveiled differences in efficacy for albendazole-ivermectin combination therapy in both countries. A pharmacometrics approach was used to assess co-medication and study population effects on the pharmacokinetics of the two main metabolites of albendazole. An exploratory exposure-efficacy analysis was also carried out to investigate relationships between exposure measures and the egg reduction rate. Pharmacokinetic data from studies in Tanzania and Côte d'Ivoire in adolescents (aged 12-19 years) were included in the pharmacometric analysis. Participants received a single dose of either albendazole 400 mg alone or in combination with ivermectin 200 µg/kg. A pharmacometric analysis was performed to investigate the potential effects of the study population and co-administered ivermectin on the apparent clearance of the metabolites of albendazole. Non-linear mixed-effects modeling was conducted with MonolixSuite 2023R1. The pharmacokinetic exposure measures derived from simulations with individual model parameters were used in the exploratory-exposure response analysis. Pharmacokinetic profiles were best described by a two-compartment model for albendazole sulfoxide and a one-compartment model for albendazole sulfone, with a transit compartment and linear elimination. While no co-medication effect was found, apparent clearance of albendazole sulfoxide (albendazole sulfone) in the Tanzanian study population was 75% (46%) higher than that in the Côte d'Ivoire study population. Exposure-efficacy response analyses indicated that peak concentration and the time-above-exposure threshold were associated with the egg reduction rate. Study population but not co-administered ivermectin showed an effect on apparent clearance of albendazole sulfoxide and albendazole sulfone. Polymorphisms in drug-metabolizing enzymes and host-parasite interaction may explain this result. Difference in drug exposure did not explain the disparate efficacy responses in Tanzania and Côte d'Ivoire. Peak concentration and time-above-threshold were exposure measures associated with the egg reduction rate. Further studies evaluating genetic and resistance patterns in various regions in Africa are warranted.

Simultaneous LC-MS/MS Method for the Quantitation of Probenecid, Albendazole, and Its Metabolites in Human Plasma and Dried Blood Spots

Millions of individuals throughout the world suffer from lymphatic filariasis (LF), which is a morbid disease caused by Wuchereria bancrofti, Brugia malayi, and Brugia timori. These infections belong to tissue-invading nematodes and are one of the major neglected tropical diseases that often result in permanent and enduring disability among individuals in endemic regions. Due to combination therapy, LF eradication has drastically decreased infections globally. The development of blood micro-sampling techniques allowing precise quantitation of drugs in blood would facilitate pharmacokinetic (PK) studies in remote populations. Therefore, an LC-MS/MS bioanalytical method was utilized to analyze albendazole (ABZ), albendazole sulfone (ABZ-ON), albendazole sulfoxide (ABZ-OX), and probenecid (PR) in plasma and dried blood spots. Solid-phase extraction was utilized to extract the analyte from both plasma and blood-spiked DBS. Analytes of interest were eluted with a gradient mobile system using 0.05% formic acid in water (A) and 0.05% formic acid in methanol (B) and separated using a reversed-phase Acquity ®BEH C18 UPLC column (100 × 2.1 mm, 1.7 µm). Precision and accuracy at each QC level were within the acceptable limit, i.e., ±15% for all analytes in both the matrices. Tests for stability under laboratory and storage conditions indicated that no notable changes were observed for plasma and DBS. The LC-MS/MS method demonstrated its capability to consistently identify all target analytes (ABZ, ABZ-ON, ABZ-OX, and PR) at low concentrations, even at the small specimen volumes obtained from DBS cards. This confirms the efficacy and durability of DBS cards as a micro-sampling technique. Moreover, it enhances collection efforts for therapeutic drug monitoring in remote locations for patients infected with lymphatic filariasis.

Development and validation of stability indicating UPLC methods for related substances and assay analyses of ricobendazole hydrochloride

Ricobendazole hydrochloride is an active ingredient of a veterinary antiparasitic drug. The aim of this study was to investigate the degradation of ricobendazole hydrochloride under stress and stability testing conditions, for which we developed and validated the first stability indicating, specific, precise, accurate, and robust assay and related substances UPLC methods. The Acquity UPLC BEH C18 column was used for the related substances and assay analyses of ricobendazole hydrochloride, and the analyses were performed at 25 °C sample and 30 °C column temperatures with a 2 µL injection volume. In both methods, a mixture of water and methanol (60:40, v/v) was used as the diluent, mobile phase A was a phosphate buffer (50 mM potassium dihydrogen phosphate solution, pH 3.2 ± 0.05, adjusted with 10% o-phosphoric acid), and mobile phase B was a mixture of mobile phase A and acetonitrile (50:50, v/v). For the analysis of related substances, a gradient elution system was used at a flow rate of 0.4 mL/min for 35 min with a detection wavelength of 220 nm, while for the assay analysis; a gradient elution system was used at a flow rate of 0.3 mL/min for 15 min with a detection wavelength of 290 nm. The calibration curves showed excellent linearity with high R-squared (R2) values for each compound, ricobendazole (0.9998, 0.249 – 3.740 µg/mL), ricobendazole amine (0.9998, 0.255 – 3.819 µg/mL), albendazole (0.9998, 0.255 – 7.646 µg/mL), and albendazole sulfone (1.0000, 0.251 – 15.090 µg/mL) indicating a strong correlation between the concentrations of the compounds and their respective peak areas in the UPLC analysis. The method showed excellent accuracy with relative standard deviation values of less than 2.5%. The stress and photostability studies showed that ricobendazole hydrochloride was insensitive to daylight and UV radiation and showed significant degradation at elevated temperature (85 °C, 9 days) and under all hydrolysis and oxidation conditions. The major impurity was ricobendazole amine under thermal and hydrolysis conditions, while albendazole sulfone was the major oxidative impurity.

Determination of benzimidazole pesticide residues in soil by ultrasound‐assisted supramolecular solvent microextraction

AbstractThe objective of this study was to develop a simple, rapid, and efficient pretreatment method using a supramolecular solvent as the extractant combined with high‐performance liquid chromatography‐ultraviolet to detect benzimidazole residues in environmental soil. The supramolecular solvent was composed of long‐chain alcohols, tetrahydrofuran, and water in proportion, showing excellent solubility and polarity range, so a supramolecular solvent microextraction method was established. The optimum method was identified by optimizing the types of long‐chain alcohols, the alcohol/tetrahydrofuran ratio, the pH, the amount of extractant, and the extraction time. The detection limits were 12.1–39.9 μg/kg with a relative standard deviation between 1.2% and 3.2% (n = 6). The recoveries ranged between 56.6% and 86.1%, and the linear relationship was good. The correlation coefficient (r2) was 0.9843 ‐ 0.9998. This method was then used to measure five benzimidazoles (thiabendazole, albendazole sulfone, ophendazole, albendazole, and fendazole) in soil samples.

An ultrahigh-performance liquid chromatography-fluorescence detection (UHPLC-FLD) method for simultaneous determination of albendazole and its three metabolites in poultry eggs

Albendazole (ABZ) is widely used in the treatment of animal intestinal parasitic infections. This study has established a method of ultrahigh-performance liquid chromatography coupled with fluorescence detection for the simultaneous determination of ABZ and its three metabolites (albendazole, albendazole sulfone, albendazole sulfoxide, albendazole-2-aminosulfone) in poultry (chicken, duck, and goose) eggs. Good linearity was shown under the optimized conditions with the determination coefficient (≥ 0.9994). The limits of detection (LOD) were 0.3–4.6 µg/kg, whereas the limits of quantification (LOQ) were 1.0–12.9 µg/kg. The recoveries of ABZ and its three metabolites ranged from 80.5% to 98.6%, while relative standard deviations were in the range of 1.2–4.8%, and all target analytes could be detected within 6 min. The method was demonstrated to be sensitive, selective, and quick for the detection of ABZ and its three metabolites.

Nanocrystal Suspensions for Enhancing the Oral Absorption of Albendazole.

Albendazole (ABZ), an effective benzimidazole antiparasitic drug is limited by its poor solubility and oral bioavailability. In order to overcome its disadvantages, ABZ nanocrystals were prepared using a novel bottom-up method based on acid-base neutralization recrystallization with high-speed mixing and dispersing. The cosolvent, stabilizer and preparation temperature were optimized using single factor tests. The physicochemical properties, solubility and pharmacokinetics of the optimal ABZ nanocrystals were evaluated. The high-performance liquid chromatography (HPLC), differential scanning calorimetry (DSC) and X-ray powder diffraction (XRD) showed that ABZ had no structural and crystal phase change after nanocrystallization. The saturated solubility of ABZ nanocrystals in different solvents was increased by 2.2–118 fold. The oral bioavailability of the total active ingredients (ABZ and its metabolites of albendazole sulfoxide (ABZSO) and albendazole sulfone (ABZSO2)) of the nanocrystals in rats was enhanced by 1.40 times compared to the native ABZ. These results suggest that nanocrystals might be a promising way to enhance the solubility and oral bioavailability of ABZ and other insoluble drugs.

Multi-residue methodology for quantification of antiparasitics in hen eggs by LC-MS/MS: development, validation and application to 348 samples from Brazil

Analytical methodology for quantification of 15 antiparasitic drugs and their respective metabolites in laying hen eggs was optimized and validated. The method uses acetonitrile as solvent extraction, sodium chloride for salting-out, low-temperature purification and analysis by LC-MS/MS. A total of 348 egg samples were collected in 11 states of Brazil and 50% of the total samples presented antiparasitic residues, which were albendazole, fipronil, fenbendazole, ivermectin, oxibendazole and mebendazole. A total of 12.4% of the samples were considered non-compliant, and residues quantified in these samples were albendazole, fipronil, and mebendazole. Albendazole was always identified as albendazole sulfone. Only one sample presented fipronil and fipronil sulfone; all others exclusively the sulfone metabolite. Fenbendazole was characterized by the presence of both metabolites: sulfone and sulfoxide. Maximum limits adopted are based on the Normative Instruction 51/2019 of the Brazilian Health Regulatory Agency (ANVISA), but albendazole, fipronil, oxibendazole, ivermectin, and mebendazole do not have their maximum residue level established. In addition, metabolites of albendazole, fipronil and fenbendazole in eggs are not considered in this Instruction.

Secretion into Milk of the Main Metabolites of the Anthelmintic Albendazole Is Mediated by the ABCG2/BCRP Transporter.

Albendazole (ABZ) is an anthelmintic with a broad-spectrum activity, widely used in human and veterinary medicine. ABZ is metabolized in all mammalian species to albendazole sulfoxide (ABZSO), albendazole sulfone (ABZSO2) and albendazole 2-aminosulphone (ABZSO2-NH2). ABZSO and ABZSO2 are the main metabolites detected in plasma and all three are detected in milk. The ATP-binding cassette transporter G2 (ABCG2) is an efflux transporter that is involved in the active secretion of several compounds into milk. Previous studies have reported that ABZSO was in vitro transported by ABCG2. The aim of this work is to correlate the in vitro interaction between ABCG2 and the other ABZ metabolites with their secretion into milk by this transporter. Using in vitro transepithelial assays with cells transduced with murine Abcg2 and human ABCG2, we show that ABZSO2 and ABZSO2-NH2 are in vitro substrates of both. In vivo assays carried out with wild-type and Abcg2-/- lactating female mice demonstrated that secretion into milk of these ABZ metabolites was mediated by Abcg2. Milk concentrations and milk-to-plasma ratio were higher in wild-type compared to Abcg2-/- mice for all the metabolites tested. We conclude that ABZ metabolites are undoubtedly in vitro substrates of ABCG2 and actively secreted into milk by ABCG2.

Improvement of Albendazole Bioavailability with Menbutone Administration in Sheep.

Simple SummaryAnthelmintic drugs are among those most widely used in veterinary practice. The development of resistance to these drugs is a widespread problem, especially in small ruminants, and represents a serious threat to animal production. Thus, new possibilities to use the available pharmacological groups in a more efficient way should be explored. The objective of this study was to assess the pharmacokinetic interaction between a benzimidazole (albendazole, ABZ) and a choleretic drug (menbutone, MEN) in sheep, and it may result in greater effectivity of this drug against nematode parasites. Plasma concentrations of ABZSO (ABZ active metabolite) were higher when ABZ was administered with MEN. The proposed interaction is a simple, safe, and inexpensive way of increasing the effectivity of this anthelmintic widely used in livestock.The pharmacokinetic interaction between a benzimidazole (albendazole, ABZ) and a choleretic drug (menbutone, MEN) was evaluated in sheep. The plasma disposition of albendazole sulfoxide (ABZSO, active metabolite) and albendazole sulfone (ABZSO2, inactive metabolite) was investigated following an oral administration of albendazole (ABZ) (5 mg/kg) alone or with menbutone (MEN) (intramuscular, 10 mg/kg). Blood samples were collected over 3 days post-treatment, and drug plasma concentrations were measured by high performance liquid chromatography (HPLC). ABZSO was measured from 0.5 to 48 h, and ABZSO2 from 2 to 60 h. No parent drug was detected at any sampling time. Mean maximum plasma concentration (Cmax) and the area under the plasma concentration-time curve (AUC) were 12.8% and 21.5% higher for ABZSO when ABZ and MEN were administered together, which indicates a significant increase in the amount absorbed. The rate of absorption was not modified, with similar values for the time to reach Cmax (tmax) (11.5 h with ABZ + MEN and 10.7 h with ABZ treatment), although no significant differences were observed for these latter pharmacokinetic parameters. Regarding ABZSO2, Cmax, AUC and tmax values were similar after both treatments (ABZ or ABZ + MEN). The results obtained indicate that co-administration of ABZ and MEN may be an interesting and practical option to increase the efficacy of this anthelmintic.

Pharmacokinetic modelling and simulation to optimize albendazole dosing in hookworm- or Trichuris trichiura-infected infants to adults.

Albendazole is the most commonly used drug in preventive chemotherapy programmes against soil-transmitted helminth (STH) infections, with the standard dose of 400 mg resulting in suboptimal clinical outcomes. Population pharmacokinetic (PK) models that could inform dosing strategies are not yet available. A population pharmacokinetic model was developed based on micro-blood samples collected from 252 patients aged 2 to 65 years, infected with either hookworm or Trichuris trichiura and treated with albendazole doses ranging from of 200 to 800 mg. An exposure-response analysis was performed relating albendazole and its two metabolites to cure rates and egg reduction rates (ERR). Finally, model-based simulations were conducted to determine equivalent exposure coverage in infants to adults. A population PK model, with one distribution compartment for each compound and one peripheral compartment, following oral administration with a lag time, assuming first-order absorption and linear elimination, best described the concentration-time profiles. Clearance and volume parameters were scaled to body size (weight for albendazole and height for albendazole sulfoxide and sulfone). Dose proportionality was observed for the active metabolite, albendazole sulfoxide, but only in hookworm-infected individuals, with increasing exposure resulting in increased ERR. Exposure of sulfoxide was lowest in the tallest individuals. Pharmacometric simulations indicate that doses up to 800 mg could further increase albendazole efficacy in hookworm-infected adults, whereas the standard dose of 400 mg is sufficient in the youngest age cohorts. In the absence of evidence-based arguments for adjusting albendazole doses in T. trichiura-infected individuals, the search for new treatment options is further emphasized.

Simultaneous Determination of Albendazole and Its Three Metabolites in Pig and Poultry Muscle by Ultrahigh-Performance Liquid Chromatography-Fluorescence Detection.

A fast, simple and efficient ultrahigh-performance liquid chromatography-fluorescence detection (UPLC-FLD) method for the determination of residues of albendazole (ABZ) and its three metabolites, albendazole sulfone (ABZ-SO2), albendazole sulfoxide (ABZ-SO), and albendazole-2-aminosulfone (ABZ-2NH2-SO2), in pig and poultry muscle (chicken, duck and goose) was established. The samples were extracted with ethyl acetate, and the extracts were further subjected to cleanup by utilizing a series of liquid–liquid extraction (LLE) steps. Then, extracts were purified by OASIS® PRiME hydrophilic-lipophilic balance (HLB) solid-phase extraction (SPE) cartridges (60 mg/3 mL). The target compounds were separated on an ACQUITY UPLC® BEH C18 (2.1 mm × 100 mm, 1.7 μm) chromatographic column, using a mobile phase composed of 31% acetonitrile and 69% aqueous solution (containing 0.2% formic acid and 0.05% triethylamine). The limits of detection (LODs) and limits of quantification (LOQs) of the four target compounds in pig and poultry muscle were 0.2–3.8 µg/kg and 1.0–10.9 µg/kg, respectively. The recoveries were all above 80.37% when the muscle samples were spiked with the four target compounds at the LOQ, 0.5 maximum residue limit (MRL), 1.0 MRL, and 2.0 MRL levels. The intraday relative standard deviations (RSDs) were less than 5.11%, and the interday RSDs were less than 6.29%.

Design of experiments applied to stress testing of pharmaceutical products: A case study of Albendazole

Forced degradation tests are studies used to assess the stability of active pharmaceutical ingredients (APIs) and their formulations. These tests are performed submitting the API under extreme conditions in order to know the main degradation products in a short period of time. The results of these studies are used to assess the degradation susceptibility of APIs and to validate chromatographic analytical methods. However, most of degradation studies are performed using one-factor-at-the-time (OFAT) which does not consider the interactions between degradation variables. This work proposes the use of Design of Experiment (DoE) approach in forced degradation of albendazole (ABZ). It was used a central composite design (CCD) to evaluate the forced degradation in a multivariate way. Experiments were performed taking into account the variables pH, temperature, oxidizing agent (H2O2) and UV radiation. It was verified the influence of the variables and their interactions on the ABZ degradation. The ABZ oxidation showed to be the main degradation route for ABZ, which is strongly influenced by the temperature. The hydrolysis was relevant at alkaline medium and high temperature. LC-IT-MSn was used to identify the degradation products. It was found three known degradation products (albendazole-2-amino, albendazole sulfoxide and albendazole sulfone) and a new derivate of albendazole molecule (albendazole sulfoxide with a chlorine). This last one was isolated and characterized by UPLC-QToF-MS and NMR analyses.

Aspects of albendazole metabolism in western lowland gorillas (Gorilla gorilla gorilla) compared to humans and other species assessed by HPLC, LC‐MS, and chiral electrokinetic chromatography

AbstractThe benzimidazole anthelmintic drug albendazole becomes metabolized to chiral albendazole sulfoxide, albendazole sulfone, albendazole 2‐aminosulfone, and other metabolites. High‐performance liquid chromatography with UV absorbance and fluorescence detection, liquid chromatography with mass spectrometry, and chiral electrokinetic chromatography were used to analyze albendazole metabolites in extracts of western lowland gorilla (Gorilla gorilla gorilla) plasma of patients with alveolar echinococcosis and the data are compared to those obtained with human patient samples and to those reported for other species in the literature. The data revealed that the albendazole sulfoxide to albendazole sulfone concentration ratio in gorilla plasma is significantly smaller compared to that in samples of men, rats, dogs, and cattle. It is, however, similar to what was observed in sheep and goats. The (+)‐albendazole sulfoxide to (−)‐albendazole sulfoxide enantiomeric ratio in gorilla blood determined by chiral electrokinetic chromatography was found to be >1 which is comparable to what was observed in humans, dogs, sheep, goats, and cattle but different to mice and rats. Furthermore, the electrokinetic chromatography data suggest that small amounts of albendazole 2‐aminosulfone may be present in plasma of gorillas and humans. The data gathered with the various separation‐based assays illustrate the value of technology featuring different analyte separation and detection principles. This is the first account describing aspects of the albendazole metabolism in gorillas.

DEVELOPMENT OF METHODS FOR QUANTITATIVE DETERMINATION OF ALBENDAZOLE AND ITS METABOLITES IN BIOLOGICAL TISSUES USING HPLC / FLD

This manuscript presents the results of developed method is intended for clinical and pharmaceutical studies of veterinary drugs based on the active substances albendazole ([5-(propylthio)-1H-benzimidazol-2yl]carbamic acid methyl ester) and its main metabolites, albendazole sulfoxide, albendazole sulfone, and albendazole-2- aminosulfone in sheep muscles. Tissue samples were made alkaline with sodium carbonate, extracted twice with acetonitrile and degreased with hexane. The extracts are further purified using a series of liquid-liquid extraction and solid phase extraction. After concentration and drying, the dry residue was recovered in the mobile phase. Separation was performed on an inverted phase Acclaim 120 C18 column using acetonitrile and phosphate buffer as the mobile phase. The gradient mode of eluents was used during 12 min at a flow rate of 1,8 ml/min. The peak retention time of albendazole 2-aminosulfoam is 3,0 min, albendazole sulfoxide is 3,9 min, albendazole sulfone is 4,8 min, and the retention time of albendazole peak is 6,6 min. The specificity of the analytical method was checked by comparing the chromatographic separation of a sample of muscle tissue enriched with a standard solution of a mixture of albendazole and its metabolites at the level of MDR (100 μg/kg) and a sample of muscle tissue placebo. The validation parameters of the method “recovery” and “coefficient of variation” were considered in accordance with the criteria of Council Directive 2002/657/EC. The procedure of sample preparation of fortified tissues to construct calibration graphs is described in the manuscript. The mean recovery from fortified muscle tissue in the range of 50-150 μg/kg albendazole, albendazole sulfoxide, albendazole sulfone and albendazole 2-aminosulfon was 100.2; 100.9; 100.7 and 100.2%, respectively. The average coefficient of variation for each compound was ≤ 10%.
 The method is linear in the concentration range of 25.0 - 200.0 μg/kg of each analyte. The results obtained in the study of the linearity of this technique were used to estimate the correctness and convergence. The accuracy of the measurements was evaluated by examining the known amounts of analytes added to the control muscle tissue. Recovery data are acceptable because they are within ± 10% of the target value. The method has sufficient convergence (accuracy). The evaluation of the intermediate accuracy of albendazole and its metabolites was assessed on three different days of analysis. The limit of detection for albendasole is 0.4 μg/kg. The average CV for each compound was <10%.
 The procedure was confirmed and then applied to determination albendazole and its metabolites in the sheep muscle tissue obtained after feeding animals with the veterinary drug albendazole. The HPLC/FLD method can be used for withdrawal time albendazole and its metabolites.

New and sensitive HPLC-UV method for concomitant quantification of a combination of antifilariasis drugs in rat plasma and organs after simultaneous oral administration.

A combination treatment comprising ivermectin (IVM), albendazole (ABZ) and doxycycline (DOX) is often prescribed for lymphatic filariasis patients. Nevertheless, there has not been an analytical method established and documented to determine these compounds simultaneously. Herein, we report a new high-performance liquid chromatographic method coupled with a UV detector (HPLC-UV) to quantify these drugs in plasma and organs. This developed analytical method was validated according to the International Conference on Harmonization (ICH) and US Food and Drug Administration (FDA) guidelines. The validated method was successfully employed to analyze IVM, ABZ along with its metabolites (albendazole sulfoxide (ABZ-OX) and albendazole sulfone (ABZ-ON)), and DOX in the plasma and organs of Wistar rats after simultaneous oral administration. An Xselect CSH™ C18 HPLC column was utilized as a stationary phase, with a mobile phase consisting of 0.1% v/v trifluoracetic acid in water and acetonitrile with a run time of 20 min. The calibration curves in biological samples were found to be linear across the concentration range of 0.01-5 μg mL-1 for IVM, ABZ and ABZ metabolites, and 0.025-10 μg mL-1 for DOX with an R value ≥0.998 in each case. The validated method was found to be selective, precise and accurate. Finally, the method developed in this study was deployed to assess the pharmacokinetic profiles and biodistribution of the combination of drugs after oral administration to Wistar rats. The validated HPLC-UV method in this study provides an extensive range of prospective applications for pharmacokinetic-based studies, therapeutic drug monitoring and toxicology.

Degradation of benzimidazoles by photoperoxidation: metabolites detection and ecotoxicity assessment using Raphidocelis subcapitata microalgae and Vibrio fischeri.

Benzimidazoles (BZ) are among the most used drugs to treat parasitic diseases in both human and veterinary medicine. In this study, solutions fortified with albendazole (ABZ), fenbendazole (FBZ), and thiabendazole (TBZ) were subjected to photoperoxidation (UV/H2O2). The hydroxyl radicals generated by the process removed up to 99% of ABZ, and FBZ, in the highest dosage of H2O2 (i.e., 1.125 mmol L-1; 4.8 kJ L-1). In contrast, 20% of initial TBZ concentration remained in the residual solution. In the first 5 min of reaction (i.e., up to 0.750 mmol L-1 of H2O2), formation of the primary metabolites of ABZ-ricobendazole (RBZ), albendazole sulfone (ABZ-SO2), and oxfendazole (OFZ)-was observed. However, these reaction products were converted after the reaction time was doubled. The residual ecotoxicity was investigated using the Raphidocelis subcapitata microalgae and the marine bacteria Vibrio fischeri. The results for both microorganisms evidence that the residual solutions are less harmful to these microorganisms. However, after 30 min of reaction, the treated solution still presents a toxic effect for V. fischeri, meaning that longer reaction times are required to achieve an innocuous effluent.

Simultaneous determination of albendazole, thiabendazole, mebendazole and their metabolites in livestock by high performance liquid chromatography

An analytical method using high performance liquid chromatography (HPLC) was developed for the simultaneous determination of thiabendazole, 5-hydroxythiabendazole, albendazole sulfoxide, albendazole sulfone, albendazole 2-ammosulfone and mebendazole in livestock. These six benzimidazoles were extracted with acetonitrile under basic conditions, followed by a Sep-Pak C18 cartridge cleaning procedure. The HPLC separation was achieved on a Cosmosil 5C18-MS-II column (5 μm, 4.6 ram i.d. × 250 mm) using gradient elation with acetonitrile and 0.02M sodium dihydrogen phosphate (pH 3.3), and detection was performed with photodiode array and fluorescence detector. Good linearity was observed from the calibration plot at concentrations from 0.05 to 2.50 μg/mL. Recovery studies of the analytes were performed at 0.02, 0.10 and 1.00 ppm spiked levels. The average recovery of 5-hydroxythiabendazole and mebendazole at low concentrations ranged from 71.4 to 87.1% and ranged from 81.6 to 104.3% at other concentrations, with coefficient of variation less than 5.9%. The detection limit for benzimidazoles was between 0.005-0.030 ppm under photodiode array detection and 0.004-0.020 ppm under fluorescence detection. The coefficient of variation of intra-day and inter-day assays was lower than 1.92% and 7.22%, respectively. These results indicated that the developed method had an acceptable precision. This method was applied to detect benzimidazoles in samples of pork, swine liver, beef, lamb, bovine milk and goat milk purchased from various markets in Taipei. The results showed that none of the six benzimidazoles were detected in the thirty samples.

Pharmacokinetics and tissue distribution study of liposomal albendazole in naturally Echinococcus granulosus infected sheep by a validated UPLC-Q-TOF-MS method

Albendazole (ABZ) is the first-line drug in treating echinococcosis, which is recommended by WHO. To address the poor bioavailability of albendazole, liposomal albendazole was formulated and is available in our hospital for many years. In this study, a sensitive, reliable and accurate UPLC-Q-TOF-MS method was developed and validated for the determination of albendazole and its metabolites, albendazole sulfoxide (ABZSO), albendazole sulfone (ABZSO2) and albendazole-2-aminosulfone (ABZSO2NH2) in naturally echinococcus granulosus (E. granulosus) infected sheep plasma and tissues with mebendazole (MBZ) as the internal standard (IS). Plasma and tissues samples were prepared by protein precipitation method. The separation was performed on an ACQUITY UPLC® BEH C18 column (2.1 × 50 mm, 1.7 μm) with a gradient mobile phase consisting of methanol and water containing 0.1% formic acid at 0.4 mL/min. The detection was performed on a quadrupole time-of-flight (Q-TOF) high-resolution mass spectrometer using positive electrospray ionization (ESI) source with a chromatographic run time of 6.0 min. The detection was operated using target ions of [M + H]+ at m/z 266.096 for ABZ, m/z 282.091 for ABZSO, m/z 298.086 for ABZSO2, m/z 240.081 for ABZSO2NH2 and m/z 296.104 for IS in selective ion mode, respectively. This method was validated in terms of selectivity, linearity, precision, accuracy, recovery, matrix effect, dilution effect, carryover effects, stability, calibration curve and LLOQ. All validation parameter results were within the acceptable range described in guideline for bioanalytical method validation. This method has been successfully applied to the pharmacokinetic study following single and multiple oral dose of 10 mg/kg liposomal albendazole, and tissue distribution study following multiple oral dose of 10 mg/kg, with emulsion albendazole as the reference preparation. The results in the article will provide valuable information for use in clinical applications of liposomal albendazole and also be beneficial for further development of liposomal albendazole in future studies.

Pharmacokinetics of Albendazole, Albendazole Sulfoxide, and Albendazole Sulfone Determined from Plasma, Blood, Dried-Blood Spots, and Mitra Samples of Hookworm-Infected Adolescents.

Albendazole is an effective anthelmintic intensively used for decades. However, profound pharmacokinetic (PK) characterization is missing in children, the population mostly affected by helminth infections. Blood microsampling would facilitate PK studies in pediatric populations but has not been applied to quantify albendazole's disposition. Quantification methods were developed and validated using liquid chromatography-tandem mass spectrometry to analyze albendazole and its metabolites albendazole sulfoxide and albendazole sulfone in wet samples (plasma and blood) and blood microsamples (dried-blood spots [DBS]; Mitra). The use of DBS was limited by a matrix effect and poor recovery, but the extraction efficiency was constant throughout the concentration range. Hookworm-infected adolescents were venous and capillary blood sampled posttreatment with 400 mg albendazole and 25 mg/kg oxantel pamoate. Similar half-life (t1/2 = ∼1.5 h), time to reach the maximum concentration (tmax = ∼2 h), and maximum concentration (Cmax = 12.5 to 26.5 ng/ml) of albendazole were observed in the four matrices. The metabolites reached Cmax after ∼4 h with a t1/2 of ca. 7 to 8 h. A statistically significant difference in albendazole sulfone's t1/2 as determined by using DBS and wet samples was detected. Cmax of albendazole sulfoxide (288 to 380 ng/ml) did not differ among the matrices, but higher Cmax of albendazole sulfone were obtained in the two microsampling devices (22 ng/ml) versus the wet matrices (14 ng/ml). In conclusion, time-concentration profiles and PK results of the four matrices were similar, and the direct comparison of the two microsampling devices indicates that Mitra extraction was more robust during validation and can be recommended for future albendazole PK studies.

New HPLC–MS method for rapid and simultaneous quantification of doxycycline, diethylcarbamazine and albendazole metabolites in rat plasma and organs after concomitant oral administration

A sensitive and relatively fast, cost-effective high-performance liquid chromatographic method coupled with mass spectrometer (HPLC-MS) is herein reported for the first time for a simultaneous quantification of plasma and organs concentration of three therapeutic agents that are widely used in treatment of lymphatic filariasis (LF), namely, doxycycline (DOX), diethylcarbamazine (DEC) and albendazole (ABZ) metabolites. The method was developed and validated as per ICH and FDA guidelines and successfully employed to quantify DOX, DEC and ABZ metabolites (albendazole sulfoxide (ABZ-OX) and albendazole sulfone (ABZ-ON)) in the plasma and organs of Sprague Dawley rats after oral concomitant administration of the above mentioned therapeutic agents. Importantly, a simple, one-step protein precipitation and extraction method was used to extract the four compounds efficiently with a recovery in the range of 79.88 ± 5.02%–90.71 ± 5.13%, 85.72 ± 7.22%–93.17 ± 5.55%, 94.38 ± 7.35%–101.00 ± 8.88% and 94.38 ± 7.35%–99.87 ± 10.22% in plasma and organs for DOX, DEC, ABZ-OZ and ABZ-ON, respectively. Separation of all analytes was performed on a Xselect CSH™ C18 HPLC column (Waters, 3.0 x 150 mm, 3.5 μm particle size) with gradient elution employing a mobile phase consisting of 0.1% v/v formic acid in water and methanol with a run time of 20 min. Quantification was carried out employing a single, quadruple MS detector operated with single ion monitoring (SIM) mode and the ion transitions at m/z of 445.4, 200.2, 282.3 and 298.3 for DOX, DEC, ABZ-OX and ABZ-ON respectively. The MS response for plasma samples was linear across the concentration range of 2.5–2500 ng/mL for DOX, 0.5–500 ng/mL for DEC, 1–1000 ng/mL for ABZ-OX and ABZ-ON with a correlation coefficient (r2) ≥ 0.998. The method was selective, precise and accurate. This method allowed us to get an insight into the pharmacokinetics and biodistribution of the three therapeutic agents after simultaneous oral administration to Sprague Dawley rats. This bioanalytical method could provide a reliable, reproducible and excellent tool for routine therapeutic drug monitoring of the above mentioned therapeutic agents and also support other clinical pharmacokinetic-based studies.