Development and validation of a green HPLC method for the analysis of clorsulon, albendazole, triclabendazole and ivermectin using monolithic column: Assessment of the greenness of the proposed method

Determining nine fasciolicides and three metabolite residues in milk and infant formula using solid-phase extraction and liquid chromatography-tandem mass spectrometry

A new sensitive method of liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis for nine fasciolicides (closantel, rafoxanide, oxyclozanide, niclosamide, nitroxinil, ioxynil, 4-nitro-3-(trifluoromethyl)phenol, salicylanilide, and triclabendazole) and three metabolite residues (ketotriclabnedazole, triclabendazole sulfone, and triclabendazole sulfoxide) in milk and infant formula was established. The samples were extracted and purified through solid-phase extraction and analyzed using LC-MS/MS. The proposed method demonstrated high accuracy (the average recoveries ranged from 70.5 % to 107.4 %) and high sensitivity (the limits of quantification ranged from 1.0 to 25.0 µg/kg). This method was successfully applied to determine nine fasciolicides and three metabolite residues in 45 milk and infant formula, providing technical support for the safety and quality evaluation of dairy products.

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.

Lab-made CO2 laser-engraved electrochemical sensors for ivermectin determination

The ivermectin (IVM), as a broad-spectrum antiparasitic drug, was widely prescribed to treat COVID-19 during the pandemic, despite lacking proven efficacy in combating this disease. Therefore, it is important to establish affordable devices in laboratories with minimal infrastructure. The laser engraving technology has been revolutionary in sensor manufacturing, primarily attributed to the diversity of substrates that can be employed and the freedom it provides in creating sensor models. In this work, electrochemical sensors based on graphene were developed using the laser engraving technology for IVM sensing. Through, the studies that used the techniques of cyclic voltammetry and differential pulse voltammetry, following parameter optimization, for the laser-induced graphene electrode demonstrated a mass transport governed by adsorption of the species and exhibited a linear working range of 10-100 (μmol L-1), a limit of detection (LOD) of 1.6 × 10-6 (mol L-1), a limit of quantification (LOQ) of 4.8 × 10-6 (mol L-1), and a sensitivity of 0.139 (μA μmol L-1). The developed method was successfully applied to direct analysis of pharmaceutical tablets, tap water (recovery of 94%) and synthetic urine samples (recovery between 97% and 113%). These results demonstrate the feasibility of the method for routine analyses involving environmental samples.

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.

An easy and green assay to determine albendazole and ivermectin in veterinary preparations by micellar liquid chromatography

A procedure to determine albendazole and ivermectin in veterinary formulations, like tablet, bolus, oral suspensions, and injections by micellar liquid chromatography, has been developed. Sample preparation was a batch solid-to-liquid extraction in mobile phase, consisting of a stirring step (15 min), followed by ultrasonication (15 min) and filtration of the obtained supernatant, to reach a target concentration of 2 mg/L for both analytes. Using a mobile phase of 0.15 M sodium dodecyl sulfate-6% 1-pentanol buffered at pH 3 with a 0.01 M phosphate salt, running at 1 mL/min through a C18 column, both drugs were resolved in less than 10 min. Absorbance detection wavelength was 292 nm. Procedure was validated by the guidelines of the International Council on Harmonization in terms of specificity, calibration range (0.025-5 mg/L), trueness (97.8%-102.6%), precision (<2.2%), and system suitability. The method was found easy-to-handle, low cost, safe, green, and with high sample-throughput, thus useful for routine analysis. Therefore, it represents a valuable alternative for quality control of veterinary formulations. It was applied to samples of veterinary formulations purchased from local chemists and veterinarians, and label claims were inside the acceptance criteria (95%-105%).

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.

Spectrum subtraction as a complementary method for six resolution techniques resolving overlapping spectra; application to multicomponent veterinary formulation with greenness and whiteness assessment

Mathematical filtration is an efficient tool to resolve the overlapping spectra of binary mixtures in zero or first order form. Herein, a comparative study was conducted between six economic, accurate and precise spectrophotometric methods for determination of Triclabendazole (TCB) and Levamisole HCl (LVM). Each component was resolved with minimum mathematical steps in its zero-order absorption spectrum by ratio subtraction, constant multiplication, and the recent factorized response method; coupled with spectrum subtraction. In addition, the mixture was resolved in its first derivative form by derivative subtraction, D1 constant multiplication, and the recent D1 factorized response method; coupled with spectrum subtraction. Results obtained were also compared to those obtained from constant value, concentration value, and derivative ratio methods. The linearity range was found to be either 1.0-10.0 µg/mL or 2.0-20.0 µg/mL for TCB, and 2.0-14.0 µg/mL for LVM with LOD of 0.08 µg/mL and 0.19 µg/mL, respectively. Validation of the proposed methods was performed according to VICH guidelines. Results obtained from the statistical data showed no significant difference regarding accuracy and precision compared to the reported methods. The developed spectrophotometric methods followed the principles of green analytical chemistry, in which the green assessment was done through four tools, called, National Environmental Methods Index (NEMI), Analytical Eco-Scale (AES), Green Analytical Procedure Index (GAPI) and Analytical greenness metric (AGREE). Also, a white assessment was performed using RGB model. The proposed methods could offer an economic alternative for the routine analysis of bulk materials and combined veterinary dosage form.

Adjusted green HPLC determination of nirmatrelvir and ritonavir in the new FDA approved co-packaged pharmaceutical dosage using supported computational calculations

The greening of analytical methods has gained interest in the quantitative analysis field to reduce environmental impact and improve safety health conditions for analysts. Nirmatrelvir plus ritonavir is a new FDA approved co-packaged medication developed for the treatment of COVID-19. The aim of this research was to develop green fitted HPLC method using pre experimental computational testing of different stationary phases as well as selecting mobile phase regarding to green analytical chemistry principles. Computational study was designed to test the physical interaction between nirmatrelvir and ritonavir and different columns (C8, C18, Cyano column). The study showed that the C18 column was better for simultaneous HPLC analysis of the cited drugs. Regarding to green point of view, mobile phase consisted of ethanol: water (80:20, v/v) provided an efficient chromatographic separation of nirmatrelvir and ritonavir within a short analytical run time, reasonable resolution and excellent sensitivity. Isocratic elution was performed on a selected C18 column and a green adjusted mobile phase at flow rate of 1 mL/min and UV detection at 215 nm. The chromatographic system allowed complete baseline separation with retention times of 4.9 min for nirmatrelvir and 6.8 min for ritonavir. The method succeeded to determine nirmatrelvir and ritonavir over the concentration range of 1.0-20.0 μg/mL in the pure form and in pharmaceutical dosage form. Greenness profiles of the applied HPLC method was assessed using analytical eco-scale, the green analytical procedure index and the AGREE evaluation method. The results revealed adherence of the described method to the green analytical chemistry principles. The authors hope to provide a promising challenge for achieving green goals through integrating computational tools and applying them with green assessment metrics.

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.

Electrochemical Detection of Ivermectin Used for the Treatment of COVID-19 with Glutardialdehyde-Modified Glassy Carbon Electrode

In this study, the surface of the glassy carbon electrode was modified with glutardialdehyde. The modified glassy carbon electrode showed electrocatalytic activity against ivermectin. The glassy carbon electrode modified with glutardialdehyde showed high sensitivity, selectivity, and stability in the determination of ivermectin. The peak current of glutardialdehyde oxidation obtained by differential pulse voltammetry decreased inversely with the ivermectin concentration. Ivermectin inhibited the oxidation reaction of glutardialdehyde and caused a decrease in current. This change made the analysis of ivermectin electrochemically possible. In order to demonstrate the applicability of the developed method in real samples, recovery studies were carried out in tap water and urine. The highest sensitivity (0.45 µA/((µmol·L-1)(cm2))) was achieved with urine sample and the lowest detection limit as 2.66 × 10-6 mol·L-1 was obtained with BRT solution sample.

Graphical abstract

Development and Validation of a Reversed-Phase High-Performance Liquid Chromatography (RP-HPLC) Method for Identification, Assay and Estimation of Related Substances of Ivermectin in Bulk Drug Batches of Ivermectin Drug Substance

A reversed-phase high-performance liquid chromatography (RP-HPLC) method has been developed and validated for the identification and assay of Ivermectin, including the identification and estimation of its process-related impurities and degradation products in bulk drug substance of Ivermectin. Analytes were separated on a HALO C18 column (100 mm × 4.6 mm I.D., 2.7 μm particle size) maintained at 40 °C (column temperature) with gradient elution. All analytes of interests were adequately separated within 25 min. All degradation products, process-related impurities and assay were monitored by ultraviolet detection at 254 nm. The new HPLC method described here successfully separated an isomer peak of the active pharmaceutical ingredient (API) from the major API peak. This newly separated isomer peak is around 1.2 to 1.5% (peak area) in typical API samples, and coelutes with the major API peak by all current HPLC methods. Quantitation limit of the HPLC method is 0.1% of target analytical concentration (~1.0 μg/mL). This method has been demonstrated to be accurate, robust, significantly higher degree of selectivity compared to the HPLC methods of Ivermectin drug substance reported in the literature and in the compendial HPLC methods prescribed in the current USA and European Pharmacopeia.

Development and Validation of Chemometrics-Assisted Green UPLC-MS/MS Bioanalytical Method for Simultaneous Estimation of Capecitabine and Lapatinib in Rat Plasma

A chemometrics-oriented green ultra-performance liquid chromatography-mass spectrometry/mass spectrometry method was developed and validated for the first-time simultaneous estimation of capecitabine (CAP) and lapatinib (LPB) along with imatinib (as internal standard (IS)) in rat plasma. Analytes were extracted using ethyl acetate as the liquid-liquid extraction media. In the pre-development phase, principles of analytical eco-scale were used to confirm method greenness. Subsequently, vital method variables, influencing method robustness and performance, were optimized using a chemometrics-based quality-by-design approach. Chromatography was achieved on a BEH C18 (100 × 2.1 mm, 1.7 μm) using isocratic flow (0.5 mL.min-1) of mobile phase acetonitrile (0.1% formic acid):0.002 M ammonium acetate in water as the mobile phase. The mass spectrometric detections were carried out in multiple reaction monitoring modes with precursor-to-product ion transitions with m/z 360.037 → 244.076 for CAP, m/z 581.431 → 365.047 LPB and m/z 494.526 → 394.141 for IS. The bioanalytical method validation studies were performed, ensuring regulatory compliance. Linearity (r2> 0.99) over analyte concentrations ranging from 5 and 40 ng.mL-1 was observed, while acceptable values were obtained for all other validation parameters. In a nutshell, a robust and green bioanalytical method was developed and applied for the simultaneous estimation of two anticancer agents from rat plasma.

Analytical Methods for Determination of Antiviral Drugs in Different Matrices: Recent Advances and Trends

Viruses are the main pathogenic substances that cause severe diseases in humans and other living things. They are among the most common microorganisms, and consequently, antiviral drugs have emerged to prevent and treat viral infections. Antiviral drugs are an essential drug group considering their prescription and consumption rates for different diseases and indications. Therefore, it is crucial to develop accurate and precise analytical methods to detect antiviral drugs in various matrices. Chromatographic techniques are used frequently for the quantification purpose since they allow simultaneous determination of antivirals. Electrochemical methods have also gained importance since the analysis can be performed quickly without the need for pretreatment. Spectrophotometric and spectrofluorimetric methods are used because they are simple, inexpensive, and less time-consuming methods. The purpose of this review is to present an overview of the analysis of currently used antiviral drugs from 2010 to 2021. Since studies on antiviral drugs are numerous, selected publications were reviewed in this article. The analysis of antiviral drugs was divided into three main groups: chromatographic, spectrometric, and electrochemical methods which were applied to different matrices, including pharmaceutical, biological, and environmental samples.