Reversed-phase ion-pair high-performance liquid chromatographic determination of triclabendazole metabolites in serum and urine

Simultaneous analysis of the of levamisole with triclabendazole in pharmaceuticals through developing TLC and HPLC-PDA chromatographic techniques and their greenness assessment using GAPI and AGREE methods

Two simple and rapid chromatographic methods were developed and validated for the analysis of levamisole and triclabendazole simultaneously in pure and pharmaceutical products. The first method is thin-layer chromatography (TLC) with densitometry, and the second method is high-performance liquid chromatography with PDA detection (HPLC-PDA). A Hypersil BDS C18 column with dimensions of 4.6 × 150 mm and a particle size of 5 µm was used in the HPLC-PDA method. An isocratic condition was used to carry out the separation, and the mobile phase was made up of acetonitrile and a 0.03 M potassium dihydrogen phosphate buffer in double-distilled water. The ratio of the mobile phase preparation was 70:30 (v/v), and the flow rate was 1 mL/min. A wavelength of 215 nm was employed for analyte detection. Precoated silica gel 60 F254 aluminium plates were used for the TLC method's separation. Mobile phase was made of ethyl acetate, hexane, methanol, and ammonia (69:15:15:1) for the separation. The detection wavelength selected was 215 nm. According to the International Council for Harmonization (ICH) guidelines, the proposed methods were validated and it was found that the two chromatographic methods are accurate, precise, and linear for both compounds in the range of 3.75-37.5 and 6-60 mg/L for the HPLC method for levamisole and triclabendazole, respectively and in the range of 2-14 µg/spot for the TLC method. The developed methods greenness profile was assessed using AGREE and ComplexGAPI tools.

Effect of Fascioliasis on the pharmacokinetic parameters of triclabendazole in human subjects

OBJECTIVES

To study the clinical efficacy of Triclabendazole (TCBZ) on Egyptian patients infected with Fasciola and understand the effect of Fascioliasis on the pharmacokinetics of TCBZ.

METHODS

The pharmacokinetics of TCBZ administered as a single oral dose (10 mg/kg) was investigated in both infected and parasite--free Egyptian subjects. After oral administration, TCBZ is metabolized to a sulphone and sulfoxide derivatives. The latter is responsible for the fasciolicidal activity of TCBZ, and it could be used as a marker of drug bioavailability. Blood samples were collected following the oral administration, and TCBZ sulfoxide plasma concentrations were determined by a sensitive and specific HPLC method.

RESULTS

Pharmacokinetic parameters (Cmax, AUC0-48, t1/2 and tmax) for TCBZ sulfoxide were calculated. In patients; the mean Cmax was 9.11 +/- 1.3 microg/ml, the mean AUC(0-48) was 91 +/- 10.5 microg h ml(-1), the mean t1/2 was 7.4 +/- 0.6 h, and the tmax was 3.0 +/- 0.4 h. In normal subjects, the mean Cmax was 8.48 +/- 0.92 microg/ml, the mean AUC(0-48) was 85 +/- 6.55 microg h ml(-1), the mean t1/2 was 6.2 +/- 0.357 h, and the tmax was 3 +/- 0.4 h. No significant difference could be detected in the patients as compared to normal subjects, which would suggest that Fascioliasis does not affect any of the studied parameters. No eggs in faeces could be detected following TCBZ treatment. Also, most of the clinical investigations showed significant decline back to the normal ranges post-treatment which indicates complete curing and high TCBZ efficacy.

CONCLUSION

Fasioliasis as an infective condition widely spread in Egypt has no significant effect on the pharmacokinetic parameters of the orally administered TCBZ and at the same time it is very effective against the parasite which strongly and safely suggests the use of this medication for the treatment of this infection.

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.

Simultaneous determination of triclabendazole and its sulphoxide and sulphone metabolites in bovine milk by high-performance liquid chromatography

A simple method has been developed for the simultaneous determination of triclabendazole and its metabolites (sulphoxide and sulphone) in bovine milk by reversed-phase high-performance liquid chromatography (HPLC). A milk sample was homogenized with sodium sulfate anhydrous and acetonitrile, and centrifuged. The supernatant was isolated, rinsed with n-hexane saturated with acetonitrile, and evaporated. The residue was dissolved with 0.1 M potassium dihydrogenphosphate, and 0.1 M sodium hydrogencarbonate, and then cleaned up on a Bond Elut C18 cartridge. The three compounds were separated on a Capcell Pak C18 UG 120 (5 microm, 150x4.6 mm I.D.) column and determined by UV detection at 295 nm. The mobile phase was acetonitrile-0.05 M ammonium acetate (50:50), and the flow-rate was 0.8 ml/min at 40 degrees C. The mean recoveries (n=4) were 89.1-95.0% with a relative standard deviation of 1.1-2.6%. The detection limits were 0.004-0.006 microg/g in milk. The proposed method was used to monitor raw milk samples for the market, and applied to the analysis of milk samples from 10 cows which had been administered with triclabendazole to control the liver fluke. The confirmation of the triclabendazole and its metabolites in the above milk sample has been achieved by electrospray LC-MS for the first time.

Determination of benzimidazole residues using liquid chromatography and tandem mass spectrometry

The determination of residues of benzimidazole using liquid chromatography and tandem mass spectrometry (LC-MS-MS) with ion spray ionization is described. Swine muscle tissue was spiked with a mixture of fifteen benzimidazoles, including metabolites of fenbendazole and albendazole. As clean-up procedure, an ethyl acetate extraction followed by solid-phase extraction on styrol-divinyl-benzene cartridge was used. The evaluation was performed by selecting the characteristic product ions for the benzimidazoles and using multiple reaction mode. 2-n-Butylmercaptobenzimidazole was used as internal standard. Blank muscle samples were fortified in the concentration range of 1-22 microg/kg. The limits of detection were below 6 microg/kg and the limits of quantification for most benzimidazoles were below 10 microg/kg. The matrix effect was checked using spiked muscle tissues of cattle and sheep as well as liver of cattle. Practical application will be shown by incurred egg material from laying hens treated with flubendazole. The recovery of the clean-up was mostly above 50% in muscle tissue and 70% in egg yolk.