Development Of Chromatographic Method Research Articles

A quality-by-design evaluated liquid chromatography method development and validation for the separation and quantification of nitroxoline and its impurities.

A novel, isocratic, sensitive, stability-indicating high-performance liquid chromatography method was developed for the separation and quantification of related substances in nitroxoline (NTL). The chromatographic separation has been achieved on Inertsil ODS-3V, (250 × 4.6mm, 5μm) at 240nm using ethylenediamine tetraacetic acid buffer and methanol in the ratio of 60:40 v/v as mobile phase. The performance of the method has been checked as per the International Conference on Harmonization guidelines for specificity, linearity, accuracy, precision, and robustness. Regression analysis showed a correlation coefficient value greater than 0.99 for NTL and its three impurities. The detection limit of impurities was in the range of 0.01% (0.05μg/mL)-0.22% (1.1μg/mL) indicating the sensitivity of the newly developed method. The accuracy of the method was established based on the recovery obtained between 94.7% and 104.1% for all the impurities. The percentage relative standard deviation obtained for the repeatability was less than 4.0% at the specification level for all impurities. Forced degradation was performed to establish the stability-indicating nature of the method and to know about the degradation products, the quality of a drug substance changes with time under the influence of stress conditions. Thus, the proposed method was validated and found to be specific, sensitive, linear, accurate, precise, reproducible, and beneficial for routine usage.

Design of experiment-oriented development and validation of novel bioanalytical reverse phase high performance liquid chromatography method of palbociclib in rat plasma and tissues, and its application in pharmacokinetic studies.

The current research involved the development and validation of an easy, cost-effective, and sensitive bioanalytical reverse-phase high-performance liquid chromatography method for the assessment of palbociclib (PAL) in rat plasma and kidney, liver, spleen and heart. A response surface methodology-based Box-Behnken design was used to optimize critical chromatographic conditions such as buffer pH, organic phase concentration and flow rate to attain good sensitivity, tailing factor and retention time. The conditions were: pH of buffer, 4.5; organic phase concentration, 40%; Shimpac column with 1.0ml/min flow rate. The responses were: tailing factor, 1.29 ± 0.03, sensitivity, 366,593 ± 8,592; and retention time, 4.5 ± 0.05 min. The samples were extracted by a protein precipitation method, and absolute recoveries were in the range of 88.99-95.08%. The linearity of the developed method was validated over the range 100-2,000 ng/ml (r2 ≥ 0.994) in all tested matrices. The developed bioanalytical method showed greater accuracy (0.98 and 4.01%) and precision (<4.88%). The method was optimized for the sensitive analysis of the PAL in rat plasma, and the kidney, liver, spleen and heart were effectively applied to pharmacokinetic studies.

Analytical quality by design‐based thin‐layer chromatography method development and validation for assay and content uniformity testing of the anti‐neoplastic drug Axitinib in tablet formulation

AbstractThe current study aims to develop and validate an analytical quality by design approach‐based high‐performance thin‐layer chromatographic (HPTLC) method for the analysis of Axitinib tablet samples. The chromatographic conditions in the TLC method were optimized using a three‐level full factorial design. The mobile phase composition and chamber saturation time served as the independent variables for optimization. The mobile phase used for TLC separation on pre‐coated aluminum plates with silica gel 60 F254 consisted of a mixture of ethyl acetate and isopropyl alcohol in a ratio of 9:1 (v/v). Axitinib was quantified at 330 nm using the densitometric method. Axitinib peak from tablet formulation was verified against the reference standard by comparing its single band at Rf 0.44 ± 0.02. Linearity was found to exist between 100 and 600 ng/band, with a correlation coefficient (r2) of 0.9978. The percentage recovery was obtained as 98.21%–99.05%. The system was validated by determining the parameters according to the guidelines of the International Council for Harmonization of Technical Conditions for Medical Products for Human Use. The proposed TLC method can be effectively applied to routine quality control of a pharmaceutical product.

High‐performance thin layer chromatographic method development and validation for simultaneous estimation of solifenacin succinate and silodosin using quality by design approach and greenness assessment

AbstractThe current research developed a high‐performance thin layer chromatographic method based on green analytical chemistry and integrated experimental approaches of analytical quality by design for simultaneous estimation of solifenacin succinate and silodosin. The integration was planned to reduce energy and solvent usage, maximize efficacy, and minimize any negative environmental effects. Taguchi design for screening and optimization a Box–Behnken design was used. The n‐butanol:ethanol:triethylamine (6:4:0.1, v/v/v) mobile phase and ultraviolet detection at 221 nm were used to develop the method. As per International Council for Harmonization Q2(R1) specifications, the method was validated. Rf value for solifenacin succinate and silodosin was found to be 0.29 ± 0.02 and 0.58 ± 0.02 respectively. For solifenacin succinate and silodosin, the linearity was found over the concentration ranges of 500–2500 ng/band and 800–4000 ng/band. For solifenacin succinate, the limits of detection and quantification were found to be 13.00 and 39.34 ng/band, respectively, while for silodosin, they were 33.29 and 100.86 ng/band, respectively. For solifenacin succinate, the method revealed a percent recovery ranging from 98.49% to 99.50%, while for silodosin, it exhibited a range from 98.86% to 99.79%. The tools predicted greenness score to be 63 and 0.78, respectively, indicating the proposed method to be green.

Stability indicating reversed-phase-high-performance liquid chromatography method development and validation for pyridostigmine bromide and sodium benzoate in oral solution.

The present study focuses on the development of a simple, rapid, specific, and stability-indicating HPLC method for the simultaneous analysis of pyridostigmine bromide (PGB) and sodium benzoate (SBN) in oral liquid dosage forms. Analytical techniques should enhance sensitivity and specificity for the estimation of pharmaceutical drug products. Stress studies were conducted under various International Conference on Harmonization (ICH) conditions for evaluation. The further optimized HPLC method was validated in accordance with the current ICH guidelines. Chromatographic separation was accomplished using a mobile phase consisting of a 950:50 v/v ratio of perchloric acid buffer and acetonitrile as mobile phase-A, and 100% acetonitrile as mobile phase-B. The flow rate is 1.0 mL/min, and the injection volume is 20 μL. Detection of components was carried out at 220 nm for PGB and 228 nm for SBN. The validated HPLC method demonstrated high specificity, with linearity ranging between 24 and 72 μg/mL for PGB and 5.2-15.6 μg/mL for SBN. The correlation coefficient for both drugs exceeded 0.999. The method demonstrated high accuracy, exceeding 97%. In stress studies, PGB was found to be sensitive to alkaline stress conditions. The results reveal the successful applicability of the current method for the estimation of PGB and SBN in its marketed formulation, which can be reasonably inferred to assess other formulation systems.

A perspective on the use of deep deterministic policy gradient reinforcement learning for retention time modeling in reversed-phase liquid chromatography

Artificial intelligence and machine learning techniques are increasingly used for different tasks related to method development in liquid chromatography. In this study, the possibilities of a reinforcement learning algorithm, more specifically a deep deterministic policy gradient algorithm, are evaluated for the selection of scouting runs for retention time modeling. As a theoretical exercise, it is investigated whether such an algorithm can be trained to select scouting runs for any compound of interest allowing to retrieve its correct retention parameters for the three-parameter Neue-Kuss retention model. It is observed that three scouting runs are generally sufficient to retrieve the retention parameters with an accuracy (mean relative percentage error MRPE) of 1 % or less. When given the opportunity to select additional scouting runs, this does not lead to a significantly improved accuracy. It is also observed that the agent tends to give preference to isocratic scouting runs for retention time modeling, and is only motivated towards selecting gradient scouting runs when penalized (strongly) for large analysis/gradient times. This seems to reinforce the general power and usefulness of isocratic scouting runs for retention time modeling. Finally, the best results (lowest MRPE) are obtained when the agent manages to retrieve retention time data for % ACN at elution of the compound under consideration that spread the entire relevant range of ACN (5 % ACN to 95 % ACN) as well as possible, i.e., resulting in retention data at a low, intermediate and high % ACN. Based on the obtained results, we believe reinforcement learning holds great potential to automate and rationalize method development in liquid chromatography in the future.

Enhancing analytical development in the pharmaceutical industry: A DoE-QSRR model for virtual Method Operable Design Region assessment

Recently, the pharmaceutical industry has increasingly adopted the Analytical Quality by Design (AQbD) approach for analytical development. To facilitate AQbD approach implementation in the development of chromatographic methods for determining cephalosporin antibiotics, an in silico tool capable of performing virtual DoEs was developed enabling to obtain virtual operable regions of method. To this end, the drugs cephalexin, cefazolin, cefotaxime and ceftriaxone were analyzed using four experimental designs, deriving a DoE-QSRR model and employing Monte Carlo method. The DoE-QSRR model and virtual DoEs were validated using data not used in model's construction, obtaining coefficients of determination of 84.72 % for DoE-QSRR model and over 77 % for virtual DoEs. Virtual MODRs were constructed using data from the virtual DoEs. The virtual MODRs were validated by comparing them with experimental MODRs under various scenarios, with overlap areas reaching values exceeding 84 %. Therefore, the in silico tool was considered suitable for indicating analyte trends under different analytical conditions, being capable of performing virtual DoEs for cephalosporin drugs with sufficient assertiveness to guide analytical development and allow obtaining a MODR capable of providing results of adequate quality.

Degradation Mechanism Study for Secondary Degradants in Rosuvastatin Calcium and Determination of Degradant Acetaldehyde Using Static Headspace Gas Chromatography Coupled with Matrix Precipitation

During the development of headspace gas chromatography (HSGC) method for assessing residual solvents in rosuvastatin calcium (RSV) drug substance, acetaldehyde (AA) was detected in obtained chromatograms, with a calculated concentration of up to 226 ppm. After a series of experiments, it was established that acetaldehyde originates from matrix interference due to direct degradation of Imp-C, which is accompanied by the formation of impurity at relative retention time (RRT) 2.18, without the involvement of impurity at RRT 2.31. The thermal instability of Imp-C also results in the formation of impurity at RRT 2.31 through dehydration and decarboxylation. In addition, cyclization reaction of degradant at RRT 2.18 further resulted in the generation of impurity at RRT 2.22. The structure of these three degradants, were confirmed by liquid chromatography-mass spectrometry (LC-MS), 1D and 2D nuclear magnetic resonance (NMR) measurement. In order to minimize the said matrix interference, a simple precipitation procedure was proposed as a pretreatment to mitigate the impact of Imp-C. Subsequently, an HSGC method was developed for the simultaneous determination of the degradant AA and the other five residual solvents used in RSV synthetic process. The final method was validated concerning precision, limit of detection (LOD) and limit of quantitation (LOQ), linearity, and accuracy.

Determination of isohydrafural and methyluracil in ear drops by high performance liquid chromatography

Abstract Objective The aim of current study was the development and validation of a reversed-phase high-pressure liquid chromatography (RPHPLC) method for the quantitative determination of two active ingredients, isohydrafural (IHF) and methyluracil (MU) in fixed dose combination ear drops. Methods: An efficient separation of the two compounds was achieved on a Teknokroma C1 5μm (150*4,6mm) column, with a methanol: water 60:40 (V: V) mobile phase, at 300C temperature and 0.6 mL/min flow-rate. The total analysis time was 5.5 min. Result: The verified validation parameters were: linearity, selectivity, specificity, precision (repeatability and reproducibility), robustness, limit of detection and quantification. Conclusions: Good separation and lack of interference from other chromatographic peaks, rapidanalysis times were obtained. The newly developed chromatographic method can be applied for the analysis of fixed dose combination ear drops with isohydrafural and methyluracil.

Development and validation of a high-performance thin-layer chromatography method for the quantification of α-mangostin in three lesser-known Garcinia species of Assam

Development and validation of a high-performance thin-layer chromatography method for the quantification of α-mangostin in three lesser-known Garcinia species of Assam

Development and validation of a high-performance thin layer chromatography method for the simultaneous determination of amoxicillin and clavulanic acid combinations in tablet dosage forms

A simple and sensitive high-performance thin layer chromatography (HPTLC) method was developed and validated as per the International Council for Harmonization (ICH) guidelines for the simultaneous determination of amoxicillin (AMX) and clavulanic acid (CLA) combinations in tablet formulations. Chromatography was performed on precoated glass plates with normal phase silica gel 60 F254. The mobile phase was acetone:ethyl acetate:glacial acetic acid:water (11:9:4:2 (v/v)). The plate was scanned at a wavelength of 428 nm after derivatization with ninhydrin. The validation of the method revealed that the linearity range lies between 400 and 1200 ng/band for AMX and 100–300 ng/band for CLA, with coefficients of determination of 0.9997 and 0.9966, respectively. Recoveries in standard addition accuracy studies were 100.3 % for AMX and 96.75 % for CLA. The limit of detection (LOD) and limit of quantitation (LOQ) of the developed method are 20.3 ng/band and 61.6 ng/band for AMX and 18.5 ng/band and 56.2 ng/band for CLA, respectively. The new, novel high-performance thin layer chromatography (HPTLC) method that was successfully developed in this study was applied for the simultaneous determination of AMX and CLA in their fixed-dose tablet dosage forms obtained from retail pharmacies and offered comparable results with the official British Pharmacopoeial high-performance liquid chromatography (HPLC) method.

Comparative Analysis of Anisotropic Lipophilicity of a Series of 6-Chloro-1,3,5-Triazines Determined in Reversed Phase Ultra High Performance Liquid Chromatography System

Triazine derivatives are well-known commercially available compounds used for selective weed control in different crops, such as corn and sugarcane. Some of them are considered persistent organic compounds in the environment and it is important to improve the features of herbicide formulae, to estimate their physicochemical properties and to determine their retention behavior in modern analytical techniques that can be used in the determination of pesticides in environmental samples. The present study deals with a comprehensive analysis of the chromatographic behavior of a series of 6-chloro-1,3,5-triazines with alkyl and cycloalkyl substituents, among which some compounds possess herbicidal and fungicidal activity. The anisotropic lipophilicity of triazine derivatives was determined using reversed-phase ultra high performance liquid chromatography with octadecyl and phenyl columns and applying binary (methanol/water and acetonitrile/water) and ternary (methanol/acetonitrile/water) mobile phases under isocratic conditions. The retention data were analyzed using chemometric pattern recognition methods (hierarchical cluster analysis and principal component analysis) and sum of ranking differences method. The obtained results are excellent indicators of the retention behavior and the lipophilicity of the analyzed series of triazines and can serve as an outstanding basis for the development of new chromatographic methods for the determination of triazines in environmental samples.

Chromatographic Development and Validation of High-performance Thin Layer Chromatography Method for Concurrent Estimation of Azelnidipine and S (-) Metoprolol Succinate in Bulk and Tablets

Chromatographic Development and Validation of High-performance Thin Layer Chromatography Method for Concurrent Estimation of Azelnidipine and S (-) Metoprolol Succinate in Bulk and Tablets

Development of electrochemical and stability-indicating chromatographic methods for the determination of cefprozil

Development of electrochemical and stability-indicating chromatographic methods for the determination of cefprozil

The Applicability of Chromatographic Retention Modeling on Chiral Stationary Phases in Reverse-Phase Mode: A Case Study for Ezetimibe and Its Impurities.

Mechanistic modeling is useful for predicting and modulating selectivity even in early chromatographic method development. This approach is also in accordance with current analytical quality using design principles and is highly welcomed by the authorities. The aim of this study was to investigate the separation behavior of two different types of chiral stationary phases (CSPs) for the separation of ezetimibe and its related substances using the mechanistic retention modeling approach offered by the Drylab software (version 4.5) package. Based on the obtained results, both CSPs presented with chemoselectivity towards the impurities of ezetimibe. The cyclodextrin-based CSP displayed a higher separation capacity and was able to separate seven related substances from the active pharmaceutical ingredient, while the cellulose-based column enabled the baseline resolution of six impurities from ezetimibe. Generally, the accuracy of predicted retention times was lower for the polysaccharide CSP, which could indicate the presence of additional secondary interactions between the analytes and the CSP. It was also demonstrated that the combination of mechanistic modeling and an experimental design approach can be applied to method development on CSPs in reverse-phase mode. The applicability of the methods was tested on spiked artificial placebo samples, while intraday and long-term (2 years) method repeatability was also challenged through comparing the obtained retention times and resolution values. The results indicated the excellent robustness of the selected setpoints. Overall, our findings indicate that the chiral columns could offer orthogonal selectivity to traditional reverse-phase columns for the separation of structurally similar compounds.

Development and Validation of Headspace-Gas Chromatography (HS-GC) Method for the Determination of Potential Genotoxic Impurities in Meloxicam

The development and validation of a specific Headspace-Gas Chromatography (HS-GC) method for the determination of genotoxic impurities (isopropyl chloride, propionaldehyde, 2-chloropropanol, and chloromethane) in Meloxicam. The chromatographic separation of these impurities was accomplished using a nitrogen carrier gas on a DB-624 (6% cyanopropyl phenyl + 94% dimethyl polysiloxane fused silica) (75 m x 0.53 mm, 3.0 µ) GC analytical column. The Flame Ionization Detector (FID) served as the detector with optimized temperatures set at 260°C for the detector and 240°C for the injector port. Additionally, an injection volume of 1.0 mL with a split ratio mode was employed. The performance of this method was assessed through parameters, including system suitability, specificity, linearity, range, accuracy, limit of detection (LOD), limit of quantification (LOQ) and precision. The limit of detection and limit of quantification for isopropyl chloride, propionaldehyde, 2-chloropropanol, and chloromethane were determined to be 2 and 4 ppm, respectively, and for chloromethane 0.8 and 1.6 respectively. The correlation coefficient of the linearity experiment was 0.999 for propionaldehyde, 2-chloropropanol, chloromethane and 1 for isopropyl chloride compounds. Furthermore, the accuracy assessment involved spiking the genotoxic impurities at various levels, demonstrating favourable recovery percentages well within the acceptable range of 80–120% of the limit level. These compelling results substantiate the suitability of the proposed HS-GC method for the accurate determination of isopropyl chloride, propionaldehyde, 2-chloropropanol, and chloromethane in Meloxicam.

Development of a HPLC Method for Analysis of a Combination of Clofazimine, Isoniazid, Pyrazinamide, and Rifampicin Incorporated into a Dermal Self-Double-Emulsifying Drug Delivery System.

We describe the development and validation of a new high performance liquid chromatography (HPLC) method for analysis of a combination of the first-line anti-tubercular drugs isoniazid, pyrazinamide, and rifampicin together with clofazimine. This is a unique challenge since clofazimine and rifampicin are relatively highly lipophilic drugs, whereas isoniazid and pyrazinamide are considerably more hydrophilic. Thus, clear separation of peaks and quantification of four individual drugs can present difficulties during the development of an analytical method. Detection was established at two wavelengths-254 nm for isoniazid and pyrazinamide and 320 nm for clofazimine and rifampicin. Gradient elution was employed using 0.1% aqueous formic acid (A) and acetonitrile (B); clear separation of the four drugs was achieved within 10 min. A linear relationship was indicated by a correlation coefficient (r2) of 0.9999 for each anti-tubercular drug, respectively. The limit of detection (LOD) for the individual drugs was 0.70 µg/mL (isoniazid), 0.30 µg/mL (pyrazinamide), 0.20 µg/mL (rifampicin) and 0.20 µg/mL (clofazimine). Precision experiments rendered a mean recovery percentage of 101.25% (isoniazid), 98.70% (pyrazinamide), 99.68% (rifampicin) and 97.14% (clofazimine). This HPLC method was validated and is reliable, repeatable, and accurate for the purpose of conducting simultaneous HPLC analyses of the four anti-tubercular drugs.

ACHIEVING LOW BACKGROUNDS DURING COMPOUND-SPECIFIC HYDROXYPROLINE DATING: HPLC COLUMN EFFECTS

ABSTRACT Accelerator mass spectrometry (AMS) radiocarbon (14C) dating is central to the development of robust chronologies in archaeological and paleoenvironmental contexts spanning the last 50,000 years. For dates to be accurate, samples must be free of exogenous carbon contamination. At the Oxford Radiocarbon Accelerator Unit (ORAU), considerable advancements in the dating of bone collagen have been made through the development of a high performance liquid chromatography (HPLC) method for the dating of the amino acid hydroxyproline, which can mitigate the effects of carbon contamination. However, recent changes in ligand manufacturing methods for the mixed-mode column used in the ORAU protocol (Primesep A, SIELC Technologies; IL, USA) have resulted in unacceptably high analytical backgrounds. Prior to the manufacturing change, backgrounds of &gt; 50k BP were achievable. Since the manufacturing change, a mean background of 32.5k BP has been measured. Due to column bleed, the Primesep A is therefore no longer suitable for 14C measurement of hydroxyproline from older material. Here, we present background data and the chromatography conditions used to isolate hydroxyproline using an alternative column, a preparative-scale Newcrom AH, which shows promising potential as an alternative for the routine isolation and AMS dating of hydroxyproline—especially approaching the age and mass limits of the method.

A Rapid, Simplified and Validated Reverse Phase Liquid Chromatography Method for Quantitation of Molnupiravir and Its Generic Versions

Molnupiravir, an orally active RdRp inhibitor, though originally developed to use against influenza, has become a promising therapeutic candidate for COVID-19 infection by acting as prodrug of the nucleoside analog b-d-N4-hydroxycytidine (NHC or EIDD- 931) in the isopropyl ester form. Accordingly, it has been approved by MHRA, UK in November 2021 to use against COVID-19. This work presents the development and validation of a high-performance liquid chromatography (HPLC) method for the rapid and accurate assessment of molnupiravir. The objective of this approach is to ensure the quality control of Lagevrio® capsules and their generic versions available in Bangladesh. The separation was carried out by isocratic elution through C18 column (4.6 mm × 250 mm i.d., 5 µ particle size) at 40 °C temperature at a constant flow rate of 1.0 mL/min using acetonitrile and 1% orthophosphoric acid as buffer (20:80, v/v). A 10 mL sample was injected and elution was monitored at 210 nm wavelength. The calibration curve over the concentration range of 80-120% were found to be linear (r2 = 0.9998), the %RSD for intra-day (0.31%) and inter-day (0.73%) precision indicate good precision where %recovery was found in the acceptable range of 99.9-100.4% as per ICH guidelines. The method was successfully applied to commercial pharmaceuticals, Lagevrio® and its generic versions and and the results were found to be consistent with the label claims (95-105%).

Development of a new affinity chromatography method for purification of horseradish peroxidase enzyme.

In this study, benzohydroxamic acid molecules were synthesized from methyl 4-amino-2-methoxy, methyl 4-amino-3-nitro, methyl 4-amino-3-methyl, and methyl 4-amino-3-chloro benzoate molecules, and the horseradish peroxidase (HRP) enzyme was purified in one step using the affinity chromatography technique for the first time. The IC50 and Ki values for the 4-amino 3-methyl benzohydroxamic acid molecule were 0.136 and 0.132 ± 0.054μM, respectively, while the IC50 and Ki values for the 4-amino-3-nitro benzohydroxamic acid molecule were 56.00 and 51.90 ± 9.90μM, respectively. It was found that the IC50 and Ki values for the 4-amino-3-chloro benzohydroxamic acid molecule were 218.33 and 175.67 ± 43.78μM, respectively, whereas the IC50 and Ki values for the 4-amino-2-methoxy benzohydroxamic acid molecule were 306.00 and 218.00 ± 68.80μM, respectively. The HRP enzyme was synthesized from 4-amino-2-methoxy hydroxamic acid column with a 35.97% yield 601.13 times, 4-amino-3-nitro hydroxamic acid column, with a 14.00% yield 404.11 times, 4-amino-3-methyl hydroxamic acid column with an 8.70% yield 394.88 times, and 4-amino-3-chloro hydroxamic acid column with a 4.48% yield 284.85 times. Thus, the HRP enzyme was purified in a single step with hydroxamic acids, and its molecular weight was found to be 44kDa. The optimum pH was 8.0, the optimum temperature was 15°C, and the optimum ionic strength was 0.4M for the purified HRP enzyme.