Determination of albendazole sulfoxide in human plasma by using liquid chromatography–tandem mass spectrometry

Metabolic mechanism and pharmacological study of albendazole in secondary hepatic alveolar echinococcosis (HAE) model rats

Albendazole (ABZ) is the primary treatment for alveolar echinococcosis (AE); however, its limited solubility impacts oral bioavailability, affecting therapeutic outcomes. In this study, various ABZ-solubilizing formulations, including albendazole crystal dispersion system (ABZ-CSD), albendazole hydrochloride-hydroxypropyl methylcellulose phthalate composite (TABZ-HCl-H), and albendazole hydroxyethyl sulfonate-hydroxypropyl methylcellulose phthalate composite (TABZ-HES-H), were developed and evaluated. Physicochemical properties as well as liver enzyme activity were analyzed and their pharmacodynamics in an anti-secondary hepatic alveolar echinococcosis (HAE) rat model were investigated. The formulations demonstrated improved solubility, exhibiting enhanced inhibitory effects on microcysts in HAE model rats compared to albendazole tablets. However, altered hepatic drug-metabolizing enzymes in HAE model rats led to increased ABZ levels and reduced ABZ-SO production, potentially elevating drug toxicity. These findings emphasize the importance of dose adjustments in patient administration, considering the impact of alveolar echinococcosis on rat hepatic drug metabolism.

Pharmacokinetics and Bioequivalence of 2 Azithromycin Tablet Formulations: A Randomized, Open-Label, 2-Stage Crossover Study in Healthy Volunteers

The current study aimed to assess the bioequivalence of a new branded azithromycin with the reference formulation. An open-label, randomized, 2-stage, crossover study design was implemented involving 77 healthy volunteers under fasting conditions. Each volunteer received a single dose of 250-mg azithromycin tablets test and reference formulations separated by a 21-day washout period. Twenty-two samples were collected at pre-dose and until 72 hours post-dose. Azithromycin concentrations were analyzed using a high-performance liquid chromatography-mass spectrometry validated method following a solid-phase plasma extraction. Noncompartmental analysis was carried out to estimate the pharmacokinetic parameters, which were compared between the test and reference products using a multivariate analysis of variance. The difference between C_max and AUC_0-72 of the test and reference formulation was not significant. The 94.1% confidence intervals of ln-transformed C_max and AUC_0-72 of azithromycin were within the bioequivalence acceptance limits of 80%-125%, therefore it can be concluded that the tested formulation is bioequivalent to the reference formulation.

A new approach for microextraction of trace albendazole sulfoxide drug from the samples of human plasma and urine, and water by the molecularly imprinted polymer nanoparticles combined with HPLC

In this research study, a method of dispersive-micro-solid phase extraction (D-µ-SPE) combined with molecularly imprinted polymer nanoparticles (MIP-NPs) with HPLC-UV was developed for the fast and selective detection of the trace amount of albendazole sulfoxide (ABZSO) in the biological samples. To investigate the effective factors on ABZSO microextraction by the method, central composite design (CCD) was utilized, and the optimum conditions for ABZSO microextraction were sample pH of 8.0, MIP-mass of 15 mg, sonication time of 12 min, and eluent (methanol) volume of 0.25 mL. Under the obtained optimal extraction conditions, the value for the limit of detection (LOD) and limit of quantification (LOQ) was respectively showed to be 0.074 and 0.246 ng mL^-1. In addition, the calculated peak areas exhibited a linear relationship with the ABZSO concentration ranging from 0.4 to 4200 ng mL^-1. The analyses of the samples including human plasma and urine, and water were successfully performed by the usage of the D-µ-SPE method, which was a simple and sensitive technique and a suitable alternative for the analysis of ABZSO. In the analysis of ABZSO in various samples, the recoveries at various levels of ABZSO concentrations (50, 300, and 500 ng mL^-1) were in the range of 95.7-103.0 %, and the relative standard deviations (RSDs; n = 3) varied from 2.2 to 4.4%.

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.

Assessment of the Performance of Solid Phase Extraction Based on Pipette Tip Employing a Hybrid Molecularly Imprinted Polymer as an Adsorbent for Enantioselective Determination of Albendazole Sulfoxide

Herein, an organic–inorganic hybrid molecularly imprinted polymer (MIP) was successfully synthesized with albendazole sulfoxide (ABZSO) as a template and 3-(trimethoxysilyl)propyl methacrylate, a bifunctional group compound, as a single cross-linking agent. In this study, a simple method using HPLC–DAD was developed for the determination of ABZSO enantiomers in human urine using pipette tip-based molecularly imprinted polymer solid phase extraction (PT–MIP–SPE). Enantioseparation with satisfactory retention times (5.17 and 7.09 min), acceptable theoretical plates (N = 4,535 and 5,091) and strong resolution (Rs = 5.45) was performed with an Agilent® Eclipse Plus C18 (100 mm × 4.6 mm, 3.5 μm) coupled with a Chiralpak® IA column (100 mm × 4.6 mm, 3 μm), a mixture with ethanol:water (50:50, v/v) as the mobile phase, temperature at 40°C, flow rate at 0.9 mL min−1 and λ = 230 nm. Thereafter, certain parameters affecting the PT–MIP–SPE were investigated in detail and the better conditions were: 300 μL of water as washing solvent, 500 μL of ethanol:acetic acid (9:1, v/v) as eluting solvent, 20 mg of MIP, 500 μL of human urine at pH 9 and no addition of NaCl. Recoveries/relative standard deviation (RSD%) for (R)-(+)-ABZSO and (S)-(−)-ABZSO were 78.2 ± 0.2% and 69.7 ± 1.7%, respectively.

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 (t _1/2 = ∼1.5 h), time to reach the maximum concentration (t _max = ∼2 h), and maximum concentration (C _max = 12.5 to 26.5 ng/ml) of albendazole were observed in the four matrices. The metabolites reached C _max after ∼4 h with a t _1/2 of ca. 7 to 8 h. A statistically significant difference in albendazole sulfone's t _1/2 as determined by using DBS and wet samples was detected. C _max of albendazole sulfoxide (288 to 380 ng/ml) did not differ among the matrices, but higher C _max 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.

Simultaneous densitometric determination of anthelmintic drug albendazole and its metabolite albendazole sulfoxide by HPTLC in human plasma and pharmaceutical formulations

A new, simple, accurate and precise high-performance thin-layer chromatographic method has been developed and validated for simultaneous determination of an anthelmintic drug, albendazole, and its active metabolite albendazole, sulfoxide. Planar chromatographic separation was performed on aluminum-backed layer of silica gel 60G F₂₅₄ using a mixture of toluene-acetonitrile-glacial acetic acid (7.0:2.9:0.1, v/v/v) as the mobile phase. For quantitation, the separated spots were scanned densitometrically at 225 nm. The retention factors (R_f ) obtained under the established conditions were 0.76 ± 0.01 and 0.50 ± 0.01 and the regression plots were linear (r²  ≥ 0.9997) in the concentration ranges 50-350 and 100-700 ng/band for albendazole and albendazole sulfoxide, respectively. The method was validated for linearity, specificity, accuracy (recovery) and precision, repeatability, stability and robustness. The limit of detection and limit of quantitation found were 9.84 and 29.81 ng/band for albendazole and 21.60 and 65.45 ng/band for albendazole sulfoxide, respectively. For plasma samples, solid-phase extraction of analytes yielded mean extraction recoveries of 87.59 and 87.13% for albendazole and albendazole sulfoxide, respectively. The method was successfully applied for the analysis of albendazole in pharmaceutical formulations with accuracy ≥99.32%.

Characterizations and bioactivities of abendazole sulfoxide-loaded thermo-sensitive hydrogel

Albendazole (ABZ), a widely used anthelmintic, attributes its primary metabolite-albendazole sulfoxide (ABZSO)-as an effective agent against helminthes. For a purpose of long-lasting releasing ABZSO in a special lesion, the present study successfully manufactured ABZSO-loaded thermo-sensitive hydrogel, which was proved by FTIR and ¹H NMR, in the interim; in vitro and in vivo behaviors of the thermo-sensitive hydrogel containing ABZSO were studied too. The in vivo pharmacokinetics parameters indicated ABZSO-loaded hydrogel as a better choice for sustained release compared with simple ABZSO. Additionally, the effect of the prepared hydrogels against helminth was investigated by the lethality of Caenorhabditis elegans, the results indicated that the lethality of ABZSO-loaded hydrogel (1, 2, and 4 mg/ml, respectively) on C. elegans was higher than that of PLGA-PEG-PLGA group (P < 0.05). It suggested that the hydrogels loaded with albendazole sulfoxide could be considered highly effective against the nematode C. elegans.