Reversed-phase liquid chromatographic method with fluorescence detection for the simultaneous determination of albendazole sulphoxide, albendazole sulphone and albendazole 2-aminosulphone in sheep plasma

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.

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%.

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.

Determining anthelmintic residues in goat milk in Brazil

SUMMARY Anthelmintics are used to combat nematodes. The misuse of anthelmintics can raise the cost of milk production. The objective of this research was to determine the presence of anthelmintics in goat milk. Twenty goats were used, divided into four groups of five animals: I- animals treated with an ivermectin-based anthelmintic; II- animals treated with moxidectin; III- animals treated with levamisole hydrochloride; and IV: animals treated with albendazole. Milk samples were collected individually: before, and 1, 2, 3, 15 and 21 days after administration of the anthelmintics. Determination of anthelmintic residues was performed by liquid chromatography-mass spectrometry (LC-MS). According to the results, there was an exponential effect (P<0.05) for ivermectin and moxidectin. Moxidectin was the anthelmintic that left a residue in the milk for the longest time, up to 21 days. However, with all the anthelmintics researched, residues were below the maximum limit recommended by the inspecting agencies.

Liquid chromatography--tandem mass spectrometry method for simultaneous determination of albendazole and albendazole sulfoxide in human plasma for bioequivalence studies

An improved high performance liquid chromatography--tandem mass spectrometry (LC–MS/MS) method has been developed for sensitive and rapid determination of albendazole (ABZ) and its active metabolite, albendazole sulfoxide (ABZSO), in the positive ionization mode. The method utilized solid phase extraction (SPE) for sample preparation of the analytes and their deuterated internal standards (ISs) from 100 µL human plasma. The chromatography was carried out on Hypurity C₁₈ column using acetonitrile-2.0 mM ammonium acetate, pH 5.0 (80:20, v/v) as the mobile phase. The assay exhibited a linear response over the concentration range of 0.200–50.0 ng/mL for ABZ and 3.00–600 ng/mL for ABZSO. The recoveries of the analytes and ISs ranged from 86.03%–89.66% and 89.85%–98.94%, respectively. Matrix effect, expressed as IS-normalized matrix factors, ranged from 0.985 to 1.042 for the both analytes. The method was successfully applied for two separate studies in healthy subjects using single dose of 400 mg conventional tablets and 400 mg chewable ABZ tablets, respectively.

Determination of albendazole and metabolites in silkworm Bombyx mori hemolymph by ultrafast liquid chromatography tandem triple quadrupole mass spectrometry

Albendazole is a broad-spectrum parasiticide with high effectiveness and low host toxicity. No method is currently available for measuring albendazole and its metabolites in silkworm hemolymph. This study describes a rapid, selective, sensitive, synchronous and reliable detection method for albendazole and its metabolites in silkworm hemolymph using ultrafast liquid chromatography tandem triple quadrupole mass spectrometry (UFLC-MS/MS). The method is liquid-liquid extraction followed by UFLC separation and quantification in an MS/MS system with positive electrospray ionization in multiple reaction monitoring mode. Precursor-to-product ion transitions were monitored at 266.100 to 234.100 for albendazole (ABZ), 282.200 to 208.100 for albendazole sulfoxide (ABZSO), 298.200 to 159.100 for albendazole sulfone (ABZSO₂) and 240.200 to 133.100 for albendazole amino sulfone (ABZSO₂-NH₂). Calibration curves had good linearities with R² of 0.9905–0.9972. Limits of quantitation (LOQs) were 1.32 ng/mL for ABZ, 16.67 ng/mL for ABZSO, 0.76 ng/mL for ABZSO₂ and 5.94 ng/mL for ABZSO₂-NH₂. Recoveries were 93.12%–103.83% for ABZ, 66.51%–108.51% for ABZSO, 96.85%–105.6% for ABZSO₂ and 96.46%–106.14% for ABZSO₂-NH₂, (RSDs <8%). Accuracy, precision and stability tests showed acceptable variation in quality control (QC) samples. This analytical method successfully determined albendazole and its metabolites in silkworm hemolymph in a pharmacokinetic study. The results of single-dose treatment suggested that the concentrations of ABZ, ABZSO and ABZSO₂ increased and then fell, while ABZSO₂-NH₂ level was low without obvious change. Different trends were observed for multi-dose treatment, with concentrations of ABZSO and ABZSO₂ rising over time.

Review of methodology for the determination of benzimidazole residues in biological matrices

Benzimidazoles are anthelmintic agents widely used in the treatment of parasitic infections in a range of species and as fungicidal agents in the control of spoilage of crops during storage and transport. In this paper, the more important benzimidazoles are introduced and their pharmacological effects and physiochemical properties discussed. The metabolism of these drugs is described relating to the occurrence and persistence of residues in biological matrices, providing information for selection of suitable matrices and target residues for testing. Methods for determination of benzimidazoles are reviewed for a range of biological matrices. The importance of selecting suitable extraction and clean-up procedures is discussed, along with the difficulties encountered in adapting single residue methods to multi-residue methods. The importance of suitable detection systems for determination of benzimidazoles, namely, screening, HPLC, GC and confirmatory methods is described in detail. The future for benzimidazole residue analysis is discussed, focusing on selection of appropriate residues for screening methods and protocols for confirmation of benzimidazole residues.