Development of an Ion-Pair HPLC Method for Determination of Acebutolol in Pharmaceuticals

A simple and accurate ion-pair reversed-phase high-performance liquid chromatographic (RP-HPLC) method has been developed and validated for determination of acebutolol (ACE) in tablet dosage forms. Both ACE and ambroxol (internal standard) were well separated using a reversed phase column and a mobile phase consisting of a mixture of methanol-0.05 M acetic acid (containing 8 mM sodium 1-heptanesulfanate) (65:35 v/v) with pH adjusted to 3.2 with triethylamine. The mobile phase was pumped at 0.80 mL min^?1 flow rate and ACE was detected by diode-array detection at 240 nm. The retention times for ACE and internal standard (IS) were 4.574 and 8.236 min, respectively. A linear response (r = 0.9998) was observed in the range of 0.27–2.93 μg mL^?1 in mobile phase. The limit of detection and limit of quantification were found as 0.07 and 0.23 μg mL^?1 in the mobile phase. Validation parameters such as precision, accuracy, selectivity, reproducibility, and system suitability tests were also determined. The excipients did not interfere with the assay of ACE in tablet dosage forms. It is suggested that the proposed method can be used for routine quality control and dosage-form assay of ACE.     

An Application of Quality by Design and Analytical Greenness Assessment Approach for the Development of Erlotinib Stability Indicating Method

Pharmaceutical regulators are worried about medication quality and stability since drug degradation may result in harmful chemicals. Erlotinib (ERL) is a tyrosine kinase inhibitor associated with the epidermal growth factor receptor (EGFR) containing susceptible functional groups such as quinazoline and amine ketone, methoxy, and ethoxy leads to a reduction in pharmaceutical quality. According to the ICH-Q1A (R2) guideline, the goal of ERL stability studies is to establish its susceptibility to degradation under various environmental conditions. A novel isocratic stability–indicating liquid chromatography method has been developed using systemic quality by design (QbD) approach. The QbD strategy includes screening and optimization as phases. Placket Burman was used for primary parameters screening, and critical factors were optimized with response surface design. The prepared degradation samples (acid, base, neutral hydrolysis, oxidative, photolytic, and thermal) were separated using a Shimadzu GIST C18 column (250 mm?×?4.6 mm, 5 µm) with 15 mM ammonium formate: ACN (58:42% v/v) as mobile phase, 0.9 mL/min flow rate, and 246 nm wavelength, which was found to be LC–MS compatible. A total of six degradation products (DPs) were identified with the optimized chromatography method. The drug was sensitive toward acidic and basic hydrolysis, but it remained stable under neutral, oxidative, thermal, and photolytic stress conditions. The optimized method was sensitive, specific, and robust, with linearity ranging from 10 to 35 µg/mL, with a correlation coefficient (R²?=?0.9997). The analytical method greenness score was calculated and observed that the developed method is green.

     

Economic Electrochemical Sensors for the Determination of Eszopiclone in Pharmaceutical Formulation with Greenness Profile Assessment

Electrochemical-ion-selective-sensors offer green, rapid, economic and simple analytical-tool in pharmaceutical industry, control processes, physiological measurements and environmental monitoring. In this study, two sensors were introduced for eszopiclone (EZP) determination in pure-form and in pharmaceutical-dosage-forms using drug-ion-exchanger association complex fabrication technique. Two different ion-exchangers were used and compared, tetrakis (4-chlorophenyl) borate in sensor1 and tetraphenyl borate in sensor 2. Such sensors showed superior performance at pH 3.5 over a wide-range of EZP concentration. The proposed method was also assessed using GAPI and analytical Eco-scale. Low cost, short analysis-time, simplicity and greenness of the proposed sensors allow their use for high-through-put analysis in quality-control laboratories.     

Bioanalytical Method Development,Validation and Stability Assessment of Xanthohumol in Rat Plasma

Xanthohumol (XH) a prenylated chalcone has diverse therapeutic effects against various diseases. In the present study, a bioanalytical method was developed for XH in rat plasma using reverse phase high performance liquid chromatography. The validation of the method was performed as per ICH M10 guidelines using curcumin as an internal standard. The Isocratic elution method was used with a run time of 10 min, wherein the mobile phase ratio 0.1% v/v OPA (A): Methanol (B) was 15:85 v/v at flow rate 0.8 mL/min and injection volume of 20 µL. The chromatograms of XH and curcumin was recorded at a wavelength of 370 nm. The retention time for XH and curcumin was 7.4 and 5.8 min, respectively. The spiked XH from plasma was extracted by the protein precipitation method. The developed method was linear with R² value of 0.9996 over a concentration range of 50–250 ng/mL along with LLOQ. The results of all the validation parameters are found to be within the accepted limits with %RSD value less than 2 and the percentage recovery was found to be greater than 95%. Based on the %RSD and percentage recovery results it was confirmed that the method was precise and accurate among the study replicates. LOD and LOQ values in plasma samples were found to be 8.49 ng/mL and 25.73 ng/mL, respectively. The stability studies like freeze thaw, short term and long-term stability studies were also performed, %RSD and percentage recovery of the XH from plasma samples were within the acceptable limits. Therefore, the developed bioanalytical method can be used effectively for estimation of XH in plasma samples.     

Analytical Performance and Greenness Evaluation of Five Multi-Level Design Models Utilized for Impurity Profiling of Favipiravir,a Promising COVID-19 Antiviral Drug

In 2018, the discovery of carcinogenic nitrosamine process related impurities (PRIs) in a group of widely used drugs led to the recall and complete withdrawal of several medications that were consumed for a long time, unaware of the presence of these genotoxic PRIs. Since then, PRIs that arise during the manufacturing process of the active pharmaceutical ingredients (APIs), together with their degradation impurities, have gained the attention of analytical chemistry researchers. In 2020, favipiravir (FVR) was found to have an effective antiviral activity against the SARS-COVID-19 virus. Therefore, it was included in the COVID-19 treatment protocols and was consequently globally manufactured at large-scales during the pandemic. There is information indigence about FVR impurity profiling, and until now, no method has been reported for the simultaneous determination of FVR together with its PRIs. In this study, five advanced multi-level design models were developed and validated for the simultaneous determination of FVR and two PRIs, namely; (6-chloro-3-hydroxypyrazine-2-carboxamide) and (3,6-dichloro-pyrazine-2-carbonitrile). The five developed models were classical least square (CLS), principal component regression (PCR), partial least squares (PLS), genetic algorithm-partial least squares (GA-PLS), and artificial neural networks (ANN). Five concentration levels of each compound, chosen according to the linearity range of the target analytes, were used to construct a five-level, three-factor chemometric design, giving rise to twenty-five mixtures. The models resolved the strong spectral overlap in the UV-spectra of the FVR and its PRIs. The PCR and PLS models exhibited the best performances, while PLS proved the highest sensitivity relative to the other models.     

A Comparative Study of the Lipophilicity of Metformin and Phenformin

The results presented in this paper confirm the beneficial role of an easy-to-use and low-cost thin-layer chromatography (TLC) technique for describing the retention behavior and the experimental lipophilicity parameter of two biguanide derivatives, metformin and phenformin, in both normal-phase (NP) and reversed-phase (RP) TLC systems. The retention parameters (R_F, R_M) obtained under different chromatographic conditions, i.e., various stationary and mobile phases in the NP-TLC and RP-TLC systems, were used to determine the lipophilicity parameter (R_MW) of metformin and phenformin. This study confirms the poor lipophilicity of both metformin and phenformin. It can be stated that the optimization of chromatographic conditions, i.e., the kind of stationary phase and the composition of mobile phase, was needed to obtain the reliable value of the chromatographic lipophilicity parameter (R_MW) in this study. The fewer differences in the R_MW values of both biguanide derivatives were ensured by the RP-TLC system composed of RP2, RP18, and RP18W plates and the mixture composed of methanol, propan-1-ol, and acetonitrile as an organic modifier compared to the NP-TLC analysis. The new calculation procedures for logP of drugs based on topological indices ⁰χ^ν, ⁰χ, ¹χ^ν, M, and M^ν may be a certain alternative to other algorithms as well as the TLC procedure performed under optimized chromatographic conditions. The knowledge of different lipophilicity parameters of the studied biguanides can be useful in the future design of novel and more therapeutically effective metformin and phenformin formulations for antidiabetic and possible anticancer treatment. Moreover, the topological indices presented in this work may be further used in the QSAR study of the examined biguanides.     

HPLC Method for Determination of Rosiglitazone in Plasma

A fast and sensitive high performance liquid chromatography method for quantitative determination of rosiglitazone in human plasma has been developed. The extraction from plasma was performed using solid-phase extraction (SPE) on C4 silica (100 mg) disposable extraction cartridges (DEC). The separation of rosiglitazone and two metabolites was achieved on a Phenomenex® Synergi 4 µm MAX-RP (150 × 4.6 mm) column, protected by a guard column. The mobile phase was 0.01 M ammonium acetate, pH 7.0 - acetonitrile (65:35, v/v). (3S)-3-OH-quinidine was used as internal standard. The analytes were detected using fluorescence detection. The method was validated. The limit of quantitation was 1 ng mL⁻¹ and the detection limit was 0.25 ng mL⁻¹ for rosiglitazone in human plasma. The recovery was 90% for rosiglitazone. Linearity was observed over a range of 1-1000 ng mL⁻¹ (r²=0.9959). The intra- and inter-day precision (C.V.) did not exceed 8.7 %. Applicability of the method was demonstrated by a clinical pharmacokinetic study. A healthy volunteer received in two separate phases 4 mg and 8 mg rosiglitazone maleate as a single oral dose. Plasma concentrations were measured for 24 h in both phases.     

Assessment of analytical testing: The impact of metrics for the sustainable measurement of pharmaceuticals

Analytical metrics allow a periodic, healthy examination of methods and how they impact the environment, while ensuring that procedures are reproducible, reliable, repeatable, transferable, and of high quality. This article provides a review of current trends with analytical metrics, such as the analytical method green score (AMGS). More importantly, the AMGS impact on sample preparation, development strategy, and energy consumption considerations are provided. Finally, recent uses of metrics with specific relevance to the pharmaceutical research and development area through method transfer are covered.     

Development of a method for the determination of cefovecin in plasma by HPLC

A simple high‐performance liquid chromatography method for the determination of cefovecin in small volume plasma has been developed. Following solid‐phase extraction using Oasis HLB cartridges, samples were separated by reverse‐phase high‐performance liquid chromatography on an XBridge C₈ (3.5 µm) 4.6 × 250 mm column and quantified using ultraviolet detection at 280 nm. The mobile phase was a mixture of 10 mm ammonium acetate (pH 3.5) and acetonitrile (89:11), with a flow rate of 0.85 mL/min. The standard curve ranged from 0.1 to 200 µg/mL. Intra‐ and Inter‐assay variability for cefovecin was <10%, and the average recovery was >90%. The lower limit of quantitation was 0.1 µg/mL. This method was successfully applied to the analysis of cefovecin samples at our institution. This is also the first fully validated method with an internal standard that does not use mass spectrometry. Copyright © 2014 John Wiley & Sons, Ltd.     

Development of a HPLC Method for Analysis of Linear Alkylbenzene Sulphonates and Detection by UV and FTIR Spectroscopy Using Thermospray Interface

 A reversed-phase high performance liquid chromatography (RP-HPLC) method, with acetic acid and sodium perchlorate phase modifiers, was developed to separate a mixture of linear alkylbenzene sulphonates (LAS), containing 10 to 13 carbon atoms. The effects of methanol-water compositions and concentrations of used modifiers were investigated and compared. The separation achieved with 50 mg L⁻¹ acetic acid was found satisfactory whereas a concentration of 10 g L⁻¹ sodium perchlorate was preferred. Chromatograms obtained with UV and Fourier transform infrared (FTIR) detection showed almost similar features and HPLC-FTIR interface spectra of LAS components exhibited excellent agreement of absorption features to those of standard FTIR spectrum and no thermal degradation was found to occur. Received May 20, 1998 Revision March 25, 1999.     

高效液相色谱法同时测定烟叶中茄尼醇和辅酶Q10的含量

高效液相色谱法同时测定烟叶中茄尼醇和辅酶Q10的含量;反相高效液相色谱;二级管阵列检测器;烟叶;茄尼醇;辅酶Q10     

Novel experimental design paradigm for development of eco-friendly gradient chromatographic method for simultaneous determination of metronidazole and spiramycin

This work describes the innovative experimental design-assisted development of a green gradient chromatographic method for concomitant analysis of metronidazole (MTR) and spiramycin (SPR). Two different designs including fractional factorial and Box-Behnken designs were implemented for screening and optimization steps, respectively. The optimum chromatographic conditions involved a mobile phase consisting of ethanol and 20 mM sodium dihydrogen phosphate solution (pH adjusted to 2.5) in the ratio 2:98 (v/v) for 2 min then the ratio changed to 30:70 (v/v). The flow rate was 1.3 mL/minute. Separation and analysis were performed on X-bridge C18 (150 mm × 4.6 mm × 3.5 μm) column with diode array detector set at 230 nm. Column oven temperature was 40°C. A linear response was acquired over the range of 5–125 μg/mL for both drugs. Detection and quantitation limits were 0.86 and 2.62 μg/mL for MTR and 0.92 and 2.83 μg/mL for SPR, respectively. The method was implemented for determination of both drugs in three tablet formulations. The method was proved to be green as evaluated by three assessment tools. The application of experimental designs assists in development of a robust green chromatographic method in gradient elution mode for determination of both drugs within reasonable time.     

Development and Validation of Stability-Indicating HPLC Methods for Quantitative Determination of Pravastatin,Fluvastatin, Atorvastatin,and Rosuvastatin in Pharmaceuticals

Abstract

High-performance liquid-chromatographic (HPLC) methods were validated for determination of pravastatin sodium (PS), fluvastatin sodium (FVS), atorvastatin calcium (ATC), and rosuvastatin calcium (RC) in pharmaceuticals. Two stability-indicating HPLC methods were developed with a small change (10%) in the composition of the organic modifier in the mobile phase. The HPLC method for each statin was validated using isocratic elution. An RP-18 column was used with mobile phases consisting of methanol–water (60:40, v/v, for PS and RC and 70:30, v/v, for FVS and ATC). The pH of each mobile phase was adjusted to 3.0 with orthophosphoric acid, and the flow rate was 1.0 mL/min. Calibration plots showed correlation coefficients (r) > 0.999, which were calculated by the least square method. The detection limit (DL) and quantitation limit (QL) were 1.22 and 3.08 µg/mL for PS, 2.02 and 6.12 µg/mL for FVS, 0.44 and 1.34 µg/mL for ATC, and 1.55 and 4.70 µg/mL for RC. Intraday and interday relative standard deviations (RSDs) were <2.0%. The methods were applied successfully for quantitative determination of statins in pharmaceuticals.     

高效液相色谱柱切换技术在药代动力学与生物利用度研究中的应用

A review of the technique of HPLC column switching has been reported.It was used successifully in thestudy of pharmacokinetics and bioavailabily for seven drugs in our laboratory.It was detailed the conditionsand effective factors for determination of famotidine,mitoxantrone,gliquidone,difloxacin, ciprofloxascin,flucomzole and pseudoephedrine in blood.     

Development of an HPLC Assay Method for Lenalidomide

Chromatographic separation of lenalidomide and its impurities was achieved on an Inertsil ODS-3 V column using a mobile phase consisting of a mixture of buffer, acetonitrile and methanol in the ratio 80:8:12 v/v. Degradation studies were performed on bulk samples of lenalidomide subjected to 0.5 N hydrochloric acid, 0.5 N sodium hydroxide, 10% v/v hydrogen peroxide, heating to 60 °C and UV light at 254 nm. Degradation was observed only under base hydrolysis conditions. The developed LC method gave a mass balance close to 99.5%, proving it to be suitable for stability studies and was validated with respect to linearity, accuracy, precision and robustness.     

Validation of a Novel HPLC Method for the Determination of Raloxifene and Its Pharmacokinetics in Rat Plasma

A novel HPLC method has been developed and validated for the determination of Raloxifene in rat plasma. Samples were prepared based on a simple protein precipitation. Separation of Raloxifene in plasma was performed on a C18 column, with a mobile phase of acetonitrile–ammonium acetate. Good linearity was demonstrated in the range of 0.2–75.0 μg mL⁻¹ (r = 0.9931). The method was used to measure the concentration and pharmacokinetics of Raloxifene in rat plasma after a single oral dose, and a linear pharmacokinetic profile of Raloxifene was found.     

Simple Stereoselective HPLC Method for Studying the Isomerisation of Cefditoren Pivoxil and Its Isomeric Purity in Pharmaceuticals

A new rapid, simple and stereoselective HPLC method for studying the isomerisation of cefditoren pivoxil in bulk and its isomeric purity in dosage form was developed and validated. This kind of isomerisation could form due to the effect of temperature on analyte during the manufacturing process or improper storage of pharmaceutical formulations. The separation between cefditoren pivoxil and cefditoren ∆3 isomer was obtained with resolution not less than 2.00 in the presence of methanol and phosphate buffer at pH 5.20 (70:30, v:v) onto Luna C18 stationary phase within 15 min analysis time. Under the validated stereoselective HPLC conditions, isomeric purity of cefditoren pivoxil was successfully determined in tablets with inter and intra-days relative standard deviation ≤4.6 %.

     

An Optimized Method for the quantitation of Carboxyamidotriazole (CAI) in Human Plasma with Solid Phase Extraction and reversed Phase HPLC

Abstract

The anticancer agent CAI was quantitated from human plasma using a C-18 column with a mobile phase consisting of acetonitrile and water (each containing 0.01M ammonium acetate) pumped over a gradient at a flow rate of 1.0 mL min. The detection of CAI and the internal standard, harmine, was accomplished using a photodiode-array detector set at 264 and 323 nm, respectively. The chromatographic run time was 17.5 minutes. The plasma samples were prepared for HPLC analysis using a C-18 solid phase extraction procedure. Two calibration curves were prepared. and the assay was shown to be linear in the concentration range of 0.02 to 0.5 μg/mL for the low curve and 0.25 to 10.0 μg/mL for the high curve, with average correlation coefficients of 0.9933 and 0.9938, respectively. Intra-assay and inter-assay imprecisions were less than 10.0% with an error of accuracy of less than 11.0%. The assay was reproducible with the sensitivity needed for the prediction of CAI levels in the plasma of cancer patients.     

Pharmacokinetics of luteolin and tetra‐acetyl‐luteolin assayed by HPLC in rats after oral administration

Accurate and reproducible HPLC methods were developed and validated for the determination of concentrations of luteolin (LT) and tetra‐acetyl‐luteolin (TALT) in rat plasma. HPLC analyses were performed on an Agilent TC‐C₁₈ column protected by a guard Agilent Zorbax Eclipse Plus. The mobile phase for LT was a binary mixture of acetonitrile–water (40:60, v/v) containing 0.5% phosphoric acid at a flow rate of 1.0 mL/min, and that for TALT was a binary mixture of methanol–water (70 : 30, v/v) containing 0.5% glacial acetic acid at the same flow rate. The UV detection wavelength for both analytes was set at 350 nm. The calibration curve was linear over the range of 40–1800 ng/mL, the lower limit of quantitation was 40 ng/mL and the lower limit of detection was 20 ng/mL for both LT and TALT. The intra‐ and inter‐day precision (RSD) values for all samples were within 7.9%. The concentration–time curves of LT and TALT after oral administration (30 mg/kg) were both fitted to a two‐compartment model. The pharmacokinetic characteristics of TALT were better than that of LT in the maximum plasma concentration (C_max) and the area under the concentration–time curve (AUC). Copyright © 2010 John Wiley & Sons, Ltd.