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Background: Selpercatinib, a selective RET kinase inhibitor, is approved for treating various cancers with RET gene mutations such as RET-rearranged thyroid cancer and non-small cell lung cancer. The presence of process-related and degradation impurities in its active pharmaceutical ingredient (API) can significantly affect its safety and effectiveness. However, research on detecting these impurities is limited. Methods: This study developed and systematically validated a High-Performance Liquid Chromatography (HPLC) method for identifying selpercatinib and its related impurities. The method utilized a 4.6 mm × 250 mm chromatographic column with 5 μm particles, employing a flow rate of 1.0 mL/min, a detection wavelength of 235 nm, an injection volume of 10 μL, and a column temperature of 35°C. Mobile phase A was composed of a 9:1 ratio of water to acetonitrile, with the aqueous component adjusted to pH 2.5 and containing 2 mM potassium dihydrogen phosphate (KH2PO4) and 0.4% triethylamine. Mobile phase B was pure acetonitrile. The gradient elution program was as follows: 0–2 min, 5%B; 2–15 min, 5% to 15%B; 15–30 min, 15% to 35%B; 30–35 min, 35% to 45%B; 35–36 min, 45% to 5%B; 36–45 min, 5%B. Results: The chromatographic method established in this study was validated according to the ICH Q2 (R1) guidelines. The developed HPLC method demonstrated excellent specificity, sensitivity, stability, linearity, precision, accuracy, and robustness. It efficiently separated the impurities present in selpercatinib, thereby confirming the method's efficacy in ensuring the purity and quality of the drug. Conclusion: The chromatographic method established in this study can be used for the detection of selpercatinib and its impurities, providing significant reference value for the quality research of selpercatinib bulk drug and its preparations, and ensuring the safety of medication for patients. [ABSTRACT FROM AUTHOR]

Background/Objectives: Reference materials are essential for ensuring the accuracy and traceability of measurements in the quality control of medicinal products. This study explores new principles for the preparation of impure materials of active pharmaceutical substances, focusing on 1-(3-benzoylphenyl)ethanone ketoprofen impurity A (European Pharmacopoeia) as the reference material. Methods: The reference material was synthesised from commercially available acetanilide and benzoyl chloride. The obtained product was purified using preparative chromatography and characterised by infrared spectroscopy (IR), 1H and 13C nuclear magnetic resonance (NMR), and mass spectrometry. The structure was verified using primary research methods to confirm its identity as the target product. Results: The characterisation confirmed the structure and purity of 1-(3-benzoylphenyl)ethanone, achieving a purity of 99.86%, meeting regulatory documentation requirements. The synthesised product was demonstrated to be identical to the target compound and suitable for use as a reference material. Conclusions: The developed method provides a robust approach for the preparation and characterisation of 1-(3-benzoylphenyl)ethanone, enabling its use as a certified reference material in the quality control of medicinal products. This approach ensures compliance with regulatory standards and enhances the reliability of pharmaceutical quality assurance practices. [ABSTRACT FROM AUTHOR]

Background: Ponatinib, a third-generation tyrosine kinase inhibitor, is employed in the management of adult chronic myeloid leukemia. Nevertheless, the presence of process impurities and degradation impurities linked to ponatinib may potentially influence its effectiveness and safety. Therefore, the objective of this research was to establish a robust liquid chromatography method and systematically validate it for the detection of substances related to ponatinib. Methods: The separation of ponatinib and its impurities was conducted using an Agilent 5HC-C18 chromatographic column (4.6 mm × 250 mm, 5 μm). The mobile phase A comprised a mixture of water and acetonitrile in a 9:1 ratio, with an aqueous solution of pH 2.4 containing 2 mM potassium dihydrogen phosphate and 0.4% triethylamine. Mobile phase B, consisting of acetonitrile, was eluted in a gradient fashion. The flow rate was set at 1.0 mL/min, detection wavelength at 250 nm, column temperature at 40°C, and injection volume at 10 μL. Results: The method demonstrated high specificity, sensitivity, solution stability, linearity, precision, accuracy, and robustness. Additionally, this research unveiled a novel compound, imp-B, generated via the oxidative degradation of ponatinib. The molecular structure of the newly discovered product was elucidated through the utilization of nuclear magnetic resonance (NMR) and high-resolution mass spectrometry (HRMS). Conclusion: In conclusion, the chromatographic method developed in this study has the potential to be utilized for the detection of ponatinib and its impurities, thereby offering significant insights for quality assessment in ponatinib research. [ABSTRACT FROM AUTHOR]

Background: Pralsetinib, a targeted inhibitor of the RET enzyme, plays a critical role in the treatment of adult patients with locally advanced or metastatic non-small cell lung cancer (NSCLC) characterized by RET gene fusion mutations following platinum-based chemotherapy. Nevertheless, impurities resulting from the manufacturing and degradation of pralsetinib have the potential to impact its therapeutic effectiveness and safety profile. Methods: To address this issue, a liquid chromatography method was developed and validated for the specific identification of pralsetinib and its related impurities. The separation of pralsetinib and its related impurities was achieved via a Waters X Bridge Ci8 column with dimensions of 4.6 mm x 250 mm and a particle size of 5 ^m. Mobile phase A was composed of 20 mmol/L potassium dihydrogen phosphate (KH2PO4) and acetonitrile (ACN) at a volume ratio of 19:1, while mobile phase B consisted solely of ACN, utilizing a gradient elution technique. Detection was performed at a wavelength of 260 nm, with an injection volume of 10 ^L and a flow rate of 1.0 mL/min. Results: The chromatographic method established in this study was validated according to the ICH Q2 (R1) guidelines. The method demonstrated excellent linearity over a specific concentration range (imp-A: 0.035-10.21 ^ig/mL; imp-B: 0.09-10.16 ^g/mL; imp-C: 0.15-10.19 μg/mL; pralsetinib: 0.04-10.32 ^g/mL). Additionally, the method possesses high sensitivity, with detection limits for impurities A, B, C, and pralsetinib of 0.01, 0.03, 0.015, and 0.013 ^g/mL, respectively, and quantification limits of 0.035, 0.09, 0.05, and 0.04 ^ig/mL, respectively. In terms of specificity, stability, repeatability, accuracy, and robustness, the method met the validation acceptance criteria. Overall, the chromatographic technique established in this study can effectively separate pralsetinib and its impurities, providing reliable assurance for the accurate detection and quantification of impurities. Conclusion: The chromatographic method developed in this study can be utilized for the detection of pralsetinib and its impurities, offering a crucial reference for research on the quality of pralsetinib. [ABSTRACT FROM AUTHOR]

Currently, the therapeutic potential of complex biomolecules such as peptides has significantly enhanced the demand for analytical method development and validation for their quality control. Peptides are more complex to analyze than small molecules because of their larger size and unique physical–chemical properties, which create different challenges for analytical method development. Reversed‐phase high‐performance liquid chromatography (RP‐HPLC) with ultraviolet or mass spectrometry is the most widely used technique for analyzing peptides and related substances. In the present study, a decapeptide and its six related possible impurities were synthesized in‐house and identified. A stability‐indicating RP‐HPLC method has been developed for the estimation of the decapeptide and its related substances. The developed method was validated according to the International Conference on Harmonization guidelines for specificity, linearity, limit of detection, quantification, accuracy, precision, and robustness. The stability‐indicating capability of the proposed method was studied under the stress conditions of acid, base, oxidative, thermal, humidity, and photolytic degradation. The decapeptide peak and its degradant were found to be homogeneous and pure in the studied stress trials, with mass balance for all types of degradation exceeding 95%. It confirms the reliability and appropriateness of determining the integrity and purity of the decapeptide and its related substances. [ABSTRACT FROM AUTHOR]

To determine the paclitaxel-related substances in a paclitaxel injection (albumin-bound), it is necessary to remove human blood albumin from the sample via solid-phase extraction and subsequently perform high-performance liquid chromatography analysis. The pre-processing operation is complicated, the duration of analysis is long, and much human power and material resources are needed in the sample testing process. Thus, the purpose of this study was to develop a quick two-dimensional liquid chromatography method that requires less consumables and possesses high sensitivity. Samples were directly injected into one-dimensional solid-phase extraction columns to remove human blood albumin. Paclitaxel and its related substances in the solid-phase extraction columns were then eluted into two-dimensional analytical columns through valve switching technology. The sample pretreatment step can be omitted in this method, which allows for the analysis of paclitaxel and its related substances to be completed more quickly, within only 15 min, under the developed two-dimensional elution conditions. The established method had good linearity (R2 = 0.9994), limit of detection (0.25 μg·mL−1), limit of quantification (0.5 μg·mL−1), precision (RSD = 0.5%), and accuracy (102.53–107.97%). [ABSTRACT FROM AUTHOR]

Doxycycline hyclate (DOXH) is very important to treat acne and prevent infections caused by bacteria, so quantifying doxycycline hyclate and its related substances is crucial. In this work, All analytes of doxycycline and its related substances, including methacycline, 4‐epi doxycycline, 6‐epi doxycycline, and 2‐acetyl‐2‐carbamoyl doxycycline, were successfully separated at low concentrations in a single run utilizing the suggested isocratic high‐performance liquid chromatography method with a mobile phase comprising water:acetonitrile:perchloric acid (75:25:0.2, v/v), Phenomenex Luna C18 column (50 × 4.6 mm, 3 μm i.d.) maintained at 30°C with a flow rate of 0.7 mL/min, injection volume of 25 μL, and photodiode array detector at 269 nm. DOXH and its related substances were linear in the range of 0.25–50, 0.1–30, 0.2–35, 0.5–50, and 0.6–20 μg/mL, respectively, with correlation coefficients greater than 0.999 and good accuracy results between 98% and 102%. The method has been successfully used to determine the drug's comparative study in both generic and reference products, demonstrating the similarity between the two products. According to the International Council for Harmonization requirements, the proposed approach was validated. Additionally, the technique has effectively studied in vitro dissolution, Six Sigma, and content uniformity. [ABSTRACT FROM AUTHOR]

In total, three related substances (RS) associated with sotalol hydrochloride (STHCl) were herein identified with a novel gradient high-performance liquid chromatography (HPLC) protocol. Further characterization of these substances was then performed via liquid chromatography–mass spectroscopy (LC–MS/MS) and nuclear magnetic resonance (NMR) approaches. For these analyses, commercial STHCl samples were used for quantitative HPLC studies and the degradation of STHCl under acidic (1M HCl), alkaline (1M NaOH), oxidative (30% H2O2), photolytic (4500 Lx), and thermal stress conditions (100 °C) was assessed. This approach revealed this drug to be resistant to acidic, alkaline, and high-temperature conditions, whereas it was susceptible to light and oxidation as confirmed through long-term experiments. The putative mechanisms governing RS formation were also explored, revealing that RS3 was derived from the manufacturing process, whereas RS2 was generated via oxidation and RS1 was generated in response to light exposure. The cytotoxicity of these RS compounds was then assessed using MTT assays and acute toxicity test. Overall, this study provides details regarding the characterization, isolation, quantification, and toxicological evaluation of STHCl and associated RS compounds together with details regarding the precise, specific, and reliable novel HPLC technique, thus providing the requisite information necessary to ensure STHCl purity and safety. [ABSTRACT FROM AUTHOR]

This current analysis demonstrates the development of the related substances (RS) method for separating and quantifying BSL and its related substances from plasma using the UPLC technique. The solid phase extraction (SPE) method was employed to extract the belumosudil (BSL) and related impurities from plasma. This SPE method has been shown to have high recovery values for BSL and its related impurities. The method employed a column from Waters, specifically the X-Bridge BEH C18 150x4.6mm, 3.5µm, with a mobile phase flow rate (0.8 mL/min) and a UV-wavelength (250 nm). In this method, BSL and its impurities show good peak shapes and high resolutions. This developed method shows high sensitivity, accuracy, and precision values. While performing the stability studies, the drug was stable and it showed less than 4.53% degradation. Six different concentration solutions (BSL (25-250µg/mL) and impurities (3-18µg/mL)) were prepared for constructing linearity plots. The obtained linearity plot shows the accepted correlation coefficient (R2) value (=0.999). The Limit of detection (LOD) and Limit of quantification (LOQ) were determined using the signal-to-noise (S/N) ratio method. This UPLC method was validated according to ICH guidelines. [ABSTRACT FROM AUTHOR]

Analytical Quality by Design principles using the design of experiments were applied for the development of a capillary electrophoresis method for the determination of enantiomeric purity and chemically related impurities of tamsulosin. From initial scouting experiments, a dual cyclodextrin (CD) system composed of sulfated β‐CD and carboxymethyl‐α‐CD was selected as the chiral selector. A fractional factorial resolution V+ design was used for the identification of the critical process parameters, while a face‐centered central composite design and Monte Carlo simulations were employed for final optimization and defining the design space of the method. The experimental conditions of the working point were: 30 mM sodium phosphate buffer, pH 3.0, containing 40 mg/mL sulfated β‐CD and 7 mg/mL carboxymethyl‐α‐CD, capillary temperature 18°C, applied voltage ‐23 kV. Following the assessment of robustness by applying a Plackett‐Burman design, the method was validated according to the International Council for Harmonization of Technical Requirements for Pharmaceuticals for Human Use guideline Q2(R1). The method allowed the quantification of the chiral impurity and three other related impurities at the 0.1 % level with acceptable accuracy and precision. [ABSTRACT FROM AUTHOR]

to determine the structure of the unknown impurity generated during the preparation of sodium sivelestat, two new compounds, benzyl 2-(2-aminoacetamido)benzoylglycinate and benzyl (2-aminobenzoyl)glycylglycinate, were prepared, and the chemical structures were confirmed by 1H NMR, 13C NMR and MS data. The unknown impurity produced during the preparation of sodium sivelestat was finally identified as benzyl (2-aminobenzoyl)glycylglycinate, which laid the foundation for quality research on sodium sivelestat. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The primary objective of the research work is to develop an effective, sensitive, economical and simple reverse phase HPLC method for quantification of Sarecycline and its impurities in Sarecycline parenteral dosage form. The separation was achieved by using a stationary phase water X-Bridge shield RP18 (150 x 4.6 mm, 3.5µ) and the mobile phase consists of ammonium acetate buffer and acetonitrile in the proportion of gradient elution. The flow rate was 1.0 mL/min. Sarecycline was detected by using UV detector at the wavelength of 240 nm. The column temperature was maintained at 40°C and sample cooler temperature was maintained at 5°C, injection volume 10µL, run time was 45 minutes. The developed method was validated for various parameters as per ICH guidelines like accuracy, precision, linearity, specificity, solution stability. [ABSTRACT FROM AUTHOR]

In this research study, we developed a new rapid and simple HPLC quantitative approach for comprehensively measuring related substance impurities (LNGN N formyl; LNGN acetamide; LNGN N Boc; LNGN amino) in Linagliptin. The related substance impurities were studied by PDA detection at 225 nm after being separated on the Kromasil C18 column stationary phase. The isocratic mode elution and a flow velocity of 1.0 mL/min were performed with the 0.1% phosphoric acid having pH 2.5 and acetonitrile. The proposed approach was appropriately verified in agreement with the "International Conference on Harmonization". Linearity was demonstrated for values ranging from LOQ quantity ppm to 150% quantity ppm, with variance coefficients 0.99. The precision varied from 0.128 to 0.969% RSD and accuracy varied from 99.13% to 101.76% for four related substance impurities. The proposed approach was appropriately implemented in the quality control analysis of the linagliptin API. Stress testing on the linagliptin API is also part of this investigation. One degradant with a 10.273 min Rt was found during oxidative stress testing on linagliptin. Using LC-MS this peak was discovered to be an adduct. [ABSTRACT FROM AUTHOR]

Objective To establish a quality control method for detecting impurities in chloral hydrate raw materials, improve the quality standards and control limits of raw materials. Methods The determination methods of chloroform and halogenated carboxylic acid in chloral hydrate were established to monitor the change of impurities in chloral hydrate through stability. Results The research and establishment of chloroform and halogenated carboxylic acid methods met the requirements of relevant regulations for analytical methodology verification, which could accurately detect four impurities in raw materials and preparations by one method. Conclusion The study provides technical support for the improvement and optimization of the quality standards of chloral hydrate and preparations. It is very necessary to implement the impurity monitoring in preparation research and production process by the chloral hydrate impurity detection and the stability comparison of this product at high temperature and light, which could largely promote the safety of medication. [ABSTRACT FROM AUTHOR]

This study deals with designing and validating an HPLC procedure for the determination of favipiravir and ten favipiravir-related impurities simultaneously in favipiravir bulk forms. The ten favipiravir related substances investigated herein included 6-Bromo-3-hydroxy-amide; 6-Fluoro-3-hydroxy-nitrile; 6-Chloro-3-hydroxy-amide; Favipiravir acid; 3-Hydroxy amide; 3,6-Difluoro amide; 3,6-Dichloro amide; 6-Chloro-3-hydroxy-nitrile; 3,6-Difluoro nitrile; and 3,6-Dichloro nitrile. Column Inert Sustain C18 is used to analyze favipiravir and favipiravirrelated impurities. Mobile phases employed included 20 mM KH2PO4 (system A) and 20 mM KH2PO4: Acetonitrile combined in 700:300 (vol/vol) parts (system B,) and given to column through gradient elution. The system was examined in accordance with the ICH prerequisite and was capable of providing accurate (96.4-114.8%) and precise (0.1-0.4%) quantitative results. The peak purities measures for favipiravir and its ten impurities revealed specificity. Linearity was evidenced from the LOQ amount level to 120% amount of the specification level (0.0015 mg/mL) with R² measures > 0.999 for favipiravir and its ten related impurities. This method concluded it was beneficial for the evaluation expected. [ABSTRACT FROM AUTHOR]

• Unknown impurity in chenodeoxycholic acid drug substance is identified as dimer. • Pharmacopoeial methods being under revision required use of non-compendial methods. • APIs without CEP and APIs from outside EU are more challenging for compounding. In 2018 the Amsterdam University Medical Centre decided to prepare chenodeoxycholic acid (CDCA) capsules (also known as pharmacy compounding) for patients with the genetic metabolic disease cerebrotendinous xanthomatosis (CTX) when the product with a marketing authorization was commercially unavailable for patients. However, after reanalysis, unknown impurities were identified in the CDCA active pharmaceutical ingredient (API) using thin-layer chromatography from the European Pharmacopoeia (Ph.Eur.) monograph. Therefore, the API did not comply with the Ph.Eur. specifications for related substances and as a result, pharmacy compounding was halted and an investigation was initiated to identify and quantify the unknown impurities. Meanwhile, a second CDCA API was sourced from another manufacturer. However, this API also appeared to contain an unknown impurity. This impurity could be identified as a dimer of CDCA using reversed phase liquid chromatography mass spectrometry. Since the Ph.Eur. at the time did not describe a suitable analytical method for the quantification of this new impurity, a high pressure liquid chromatography with differential refractometer (HPLC-RI) method was developed to quantify the dimer. Subsequently, in 2019, a new draft version of the CDCA Ph.Eur. monograph was published, including the dimer as a new impurity together with a HPLC-RI method for its identification and quantification. The CDCA-dimer is classified as non-toxic and permitted in the CDCA API up to a maximum of 0.5 %. Because the API complied with the updated Ph.Eur. specifications, pharmacy compounding of CDCA capsules could be resumed. [Display omitted] [ABSTRACT FROM AUTHOR]

Literature about sterilization of pharmaceutical substances is limited. The aim of this study was to evaluate the effect of nitrogen dioxide (NO 2) sterilization, a new emerging technology, on five different ophthalmic active pharmaceutical ingredients, i.e., tetracycline hydrochloride, aciclovir, dexamethasone, methylprednisolone, and triamcinolone. The NO 2 process concentrations tested were 5, 10, and 20 mg/L. The applied temperature was 21 °C and the relative humidity 30 %. The process cycle consisted of two pulses with a dwell time of 10 min each. Non-processed samples were used as a blank. The effect of the sterilization method was assessed by high performance liquid chromatography coupled to an ultraviolet/visible detector, used for the quantitative analysis of the degradation products and the relative content of the evaluated ophthalmic medicines. For tetracycline hydrochloride and aciclovir, an increase of impurities was observed by increasing the NO 2 concentration. The maximum permissible NO 2 concentrations were estimated to be 10 mg/L and 2.5 mg/L, respectively, considering the requirement for the impurities to be within the limit stated in the European Pharmacopoeia (Ph. Eur.). For both compounds, samples subjected to 20 mg/L NO 2 demonstrated a significant difference in content compared to the non-processed sample. For methylprednisolone, dexamethasone, and triamcinolone, impurities complied with the limits of the Ph. Eur. for each NO 2 concentration and relative contents were not significantly affected. Sterilization of tetracycline hydrochloride and aciclovir with NO 2 is not recommended due to extensive degradation. NO 2 sterilization of methylprednisolone, dexamethasone, and triamcinolone could find its application within the aseptic processing procedure of related pharmaceuticals. • Effect of the gas sterilant nitrogen dioxide studied on 5 ophthalmic drugs. • Content and impurity profile determined with HPLC. • Degradation of tetracycline hydrochloride and aciclovir upon nitrogen dioxide treatment. • No pronounced effect on methylprednisolone, dexamethasone and triamcinolone. [ABSTRACT FROM AUTHOR]

This article described the development and validation of a method for spiramycin related substances based on hybrid particle column. The chromatographic conditions were as follows: water - 0.2 mol/L dipotassium hydrogen phosphate (the pH value adjusted to 9.5 using a 1 mol/L KOH solution) - acetonitrile - methanol (10: 60: 28.5: 1.5, v / v / v / v) as mobile phase A, water - 0.2 mol/L dipotassium hydrogen phosphate (pH 9.5) - acetonitrile - methanol (10: 30: 57: 3, v / v / v / v) as mobile phase B and gradient elution was performed. Compared with previous analytical methods, this method has strong specificity, excellent sensitivity and stability, which could be used for the daily testing of related substances of spiramycin. Furthermore, impurities above 0.1 % were characterized using two-dimensional liquid chromatography coupled with quadrupole time-of-flight mass spectrometer (2D LC-QTOF-MS/MS) and there were 6 impurities reported for the first time. • Optimized HPLC-UV method was developed for impurity analysis of spiramycin samples. • 2D LC-QTOF-MS/MS method was developed for the characterization of impurities in spiramycin. • 6 new impurities were reported for the first time. [ABSTRACT FROM AUTHOR]

Objectives: Olmesartan medoxomil (OLM) and metoprolol succinate (MPS) in fixed-dose combination (FDC) tablet formulation prescribed extensively. Stability indicating (SI) method for impurities and related substance (RS) test quantitates the amount of these analytes in formulation; the manuscript presents SI/RS-ultra-high performance liquid chromatography-photodiode array (UHPLC-PDA) method for OLM and MPS and their impurities. Materials and Methods: Well-resolved separation of all analytes was achieved with gradient elution on a Shimadzu on Shimpack GIST-C18 (100 mm x 2.1 mm, 2 µm) column maintained at 25°C. Mobile phase-A consist of 0.1% orthophosphoric acid in water and mobile phase-B was acetonitrile at a flow rate of 0.4 mL/min, data integrated at 225 nm and 16 min of short runtime for satisfactory elution of all peaks. Results: The proposed SI/RS-UHPLC-PDA method was developed and validated as per International Conference on Harmonisation (ICH) of Technical Requirements guidelines. The system suitability test complied by all eluted peaks of the interest with acceptable linearity, recovery, and precision. Specificity, robustness, and method sensitivity parameters were determined; all the parameters were found to be within the limits. All the impurities and stress-degraded peaks were well resolved. Conclusion: The proposed method was found to be simple, fast, linear, and accurate. Further, the method is precise, robust, and specific; suitable for routine IPQC during active pharmaceutical ingredient manufacturing, stability and impurity profiling studies of the titled bulk analytes. Furthermore, the method can be extended to assess the levels of impurities formed during life cycle of new FDCs of titled analytes. [ABSTRACT FROM AUTHOR]

Ezetimibe is an azetidinone derivative and a substituted β‐lactam, it is a hypolipidemic agent, and a drug substance that lowers the cholesterol levels in our body. The present work describes the origin, synthesis, and characterization of three impurities of ezetimibe, which are also positional isomers and/or related substances of ezetimibe. viz: o‐Fluoro benzene isomer, m‐Fluoro aniline analog, and des‐fluoro aniline analogs of ezetimibe. [ABSTRACT FROM AUTHOR]

[Display omitted] • Eltrombopag olamine was subjected to forced degradation and UPLC-ESI-MS studies were performed for major degradation products. • Known drug related substances (RS) were searched from the literature. • m / z values for major forced degradation products were correlated with known RS. • RS were subjected to Tanimoto similarity, Toxicity - ADME evaluations, and docking. • Justified entry of six RS as potential TPO receptor agonists for drug discovery. The recent pandemic has highlighted the impact of diseases on global health and the economy. The rapid discovery of new hit molecules remains a tough challenge. Pharmaceutical impurity profiling can be linked to drug discovery through the identification of new hits from compounds identified during the analytical profiling. The present study demonstrates this linkage through the extension of the impurity (forced degradation) profiling of eltrombopag (ELT) olamine, a thrombopoietin (TPO) receptor agonist. The drug was exposed to standard degradation and the degradation products were primarily resolved and identified by UPLC-ESI-MS. This led to the identification of five forced degradation products (FDP). Thirty-three other known related substances (RS) of ELT, identified in the literature, were also considered. Molecular similarity checks were performed using Tanimoto/Jaccard's similarity searches. A set of structurally and topologically similar molecules, including ELT and 15 RS, was established and subjected to in-silico toxicity-, absorption-, distribution-, metabolism-, and elimination (ADME) predictions. The RS, predicted with similar or lower toxicity than ELT and a comparable ADME profile, were subjected to molecular docking to trace changes in TPO receptor affinity. The results indicated that five RS had a high Jaccard's similarity with ELT and higher or comparable docking scores. These compounds, along with few other impurities were predicted to have lower toxicity, better or comparable absorption, distribution, metabolism, and also a better excretion profile than ELT. This justifies their entry as potential novel TPO receptor agonists in drug discovery. [ABSTRACT FROM AUTHOR]

Budesonide is an active pharmaceutical ingredient used in various dosage forms of finished products for the treatment of asthma. During the process of drug development, unbiased analysis of related substances is of utmost significance for both pharmaceutical research and quality control purposes. In this work, the official method documented in the United States Pharmacopoeia was selected to determine the related substances of budesonide considering the pros and cons of critical chromatographic parameters, compared to the European Pharmacopoeia. In doing so, several unpredictable interference peaks, namely "ghost peaks", were observed occasionally during analysis. A strategy that integrated information derived from experimental operation inspection, liquid chromatography/mass spectrometry fingerprint analysis, and mechanism‐based stress studies was then proposed for comprehensively and quickly exploring those non‐degradable and degradable peaks. Some ghost peaks were found to originate from nylon syringe filter, illumination, and alkali borosilicate glass high‐performance liquid chromatography vials. Besides, degradation pathways under alkaline conditions were also unraveled through liquid chromatography‐mass spectrometry qualitative analysis. Overall, an optimization of the analytical methodology based on the United States Pharmacopoeia for its application in impurity analysis of budesonide and corresponding formulations was carried out with the design of experiments, by which "ghost peaks" could be suppressed or prevented. The results obtained herein are not only crucial to studies on budesonide's stability or degradation kinetics but also contribute to clarifying the impurity research of other drugs. [ABSTRACT FROM AUTHOR]

A simple and sensitive high-performance liquid chromatographic (HPLC) method is established to separate and quantify the related substance present in two alkylating agents. The use of the traditional approach of analytical validation, in practice or in the literature, is communal. However, statistical verification, that looks separately the two errors (such as absolute bias and repeatability) to make a decision, presents a risk to declare that an analytical method is valid while it is not, or equally. To minimize this peril, a new approach based on the concept of total error was proposed. In this paper, we reveal the applicability and simplicity of the both methods based on the total error approach: accuracy profile and uncertainty profile. Proposed study demonstrated by validation case of a liquid chromatographic LC method for the quantification of related compounds present in two alkylating agents. Both methods showed good linearity response (> 0.995) with repeatability (%relative standard deviation less than 2%) and accuracy (94 to 106%). Accuracy profile was found within the range of ±10% and risk profile ±5% between the two series respectively. The excellence of the total error approach was presented since it enables successfully to validate the analytical procedure as well the calculation of the measurement uncertainty at each concentration level. [ABSTRACT FROM AUTHOR]

A simple, rapid, and robust reverse phase HPLC method was developed and validated for the determination of related substances for Dolutegravir dispersible tablets 10mg. The primary goal of this research is to develop and validate a new RP-HPLC method for validating the amount of Impurity B (degradation impurity) as a related substance following USP guidelines. Dolutegravir and its impurities were separated using chromatographic conditions on a Phenyl-Hexyl (250 × 4.6 mm), 5µ column with a 45 % buffer (sodium dihydrogen phosphate dihydrate and EDTA): 49 % methanol: 6 % acetonitrile mixture and a pH of 2.5 ± 0.05 adjusted with orthophosphoric acid. The flow rate in isocratic elution mode was 1.2 mL/min. The column temperature was kept constant at 35°C, and the eluted compounds were measured at a wavelength of 258 nm using the PDA detector. According to USP guidelines, the developed method was tested and found to be stability-indicating, specific, rugged, precise, linear, accurate, and robust, with a high resolution and shorter retention time. The system suitability and other validation parameters were found to be within the limits. The method was sensitive because the LOD and LOQ demonstrate its sensitivity. The linearity curves for Dolutegravir and Impurity B were found to be linear, with a correlation coefficient of at least 0.997. The average percentage of impurities recovered ranged between 80 % to 120 %. As a result, the proposed method was found to be good and accurate for the quantitative determination of related substances associated with Dolutegravir dispersible tablets 10mg. [ABSTRACT FROM AUTHOR]

The research focus of this work was development and validation of an efficient analytical method that can be used for separation and determination of related substances of bisoprolol in finished drug product using reversed-phase HPLC with UV-DAD. In a previous systematic study of various stationary phases and elution conditions it was found that several octadecylsilane phases can be successfully employed for separation of the critical pairs of bisoprolol and its related degradation products. Namely, method development led to conclusions that satisfactory resolution and peak shapes were obtained with gradient elution with water with 0.2% perchloric acid and acetonitrile and the reversed-phase columns: Hypersil 3 BDS C18 (100 x 4 mm, 3 µm); Zorbax SB C18 (150 x 4.6 mm, 3.5 µm); Acquity UPLC BEH C18 (50 x 2.1 mm, 1.7 µm), and Xterra MS C18 (100 x 4.6 mm, 3.5 µm). Since regular quality control includes the parameter related substances, which is of great importance for the overall quality of dosage forms, this study was oriented towards widening the available validated analytical methods for determination of this parameter. In this work, the results from the validation of the method for determination of related substances of bisoprolol using Zorbax SB C18 150 x 4.6 mm, 3.5 µm, are presented. Validation parameters that were tested (linearity, accuracy, precision, selectivity) confirmed that the method is suitable for its intendance and it was used for characterization of the samples from a forced degradation study of bisoprolol tablets. [ABSTRACT FROM AUTHOR]

In this study, a simple stability-indicating HPLC method for determination of folic acid and its related substances in tablets was optimized and validated. Chromatographic separation was performed on Inertsil C8, 250 x 4.6 mm, 5 µm, using isocratic elution with mobile phase consisting of methanol and phosphate buffer (pH=6,4) (12:88, v/v %). The injection volume was 5 µL and the eluted compounds were monitored at 280 nm. The flow rate was 0.7 mL/min and the column temperature was maintained at 30 °C. Forced degradation studies were conducted to investigate the stability-indicating ability of the method. The method was validated according to the ICH guideline requirements with respect to selectivity/specificity, linearity, limit of detection, limit of quantification, accuracy, precision and robustness. The results from the forced degradation study confirmed satisfactory resolution between folic acid and obtained specified impurities (imp. A, imp. C, imp. D, imp. E and PABA) as well as satisfactory resolution between all other formed degradation products, proving that the method is stability-indicating. The optimized and validated method is selective and precise, capable of detecting and quantifying all folic acid related substances. The obtained results from validation parameters imply that the proposed method is suitable for its purpose and can be used for routine quantification of folic acid and its related substances in tablets. [ABSTRACT FROM AUTHOR]

Eltrombopag is an oral non-peptide thrombopoietin receptor (TPO-R) agonist indicated for the treatment of thrombocytopenia in patients with persistent or chronic immune thrombocytopenia (idiopathic thrombocytopenic purpura, ITP) or chronic hepatitis C infection and the treatment of severe aplastic anemia. The purpose of this research was to assess the possible impurities that may carry over to eltrombopag from its precursor Eltro-1 (3′-amino-2′-hydroxy-[1,1′-biphenyl]-3-carboxylic acid) and to develop a specific analytical method for the determination of these impurities. Eltro-1 samples synthesized by two different synthesis routes were investigated during the evaluation and method development studies. Besides the expected process-related impurities (Eltro-1A – Eltro‐1J), e.g., starting materials, intermediates, and/or compounds formed from their further reactions, an unknown impurity detected above 0.10% was identified by LC-MS, synthesized and fully characterized by NMR, MS and FTIR (Eltro‐1K). Accordingly, an HPLC-RP method for the determination of eleven impurities (Eltro-1A – Eltro‐1K) in Eltro-1 was developed and validated according to ICH Q2. The control limits for impurities in Eltro-1 were set at ≤ 0.15% for Eltro-1A – Eltro‐1J and ≤ 1.0% for Eltro‐1K based on fate, spike-purge and carryover studies and in accordance with the ICH M7 classification for impurities in drug substance. Eltro-1 and eleven impurities at the specification limit were separated from each other and the diluent peaks with sufficient resolution without interference. Separation was performed on a Waters XBridge C 18 column (150 × 4.6 mm, 3.5 μm) at 40 °C with a 10 µL injection volume at a detection wavelength of 220 nm and 15 °C sample temperature. The gradient elution is performed at a flow rate of 1.0 mL/min for 40 min with mobile phase A (0.1% orthophosphoric acid in water) and B (acetonitrile) according to the following program: Time (min) / Acetonitrile (%): 0/0, 35/70, 36/0, 40/0. Test and standard solutions were prepared at a concentration of 1.0 mg/mL and 1.0 µg/mL, respectively, using a mixture of mobile phase A and acetonitrile (75/25) as diluent. This is the first specific, selective, sensitive, linear, precise, accurate, and robust HPLC method for the determination of Eltro-1A – Eltro‐1K in Eltro-1, which showed no significant degradation under thermal stress, photostability (UV and VIS), and standard accelerated and long-term stability conditions. [Display omitted] • Evaluation of potential eltrombopag impurities from its precursor Eltro-1. • Identification (LC-MS), synthesis and characterization (NMR, MS, FTIR) of Eltro-1K. • Justification of Eltro-1K limit in Eltro-1 by fate and spike-purge study. • Development and validation (ICH Q2) of LC related substances method for Eltro-1. • The specificity of the method was also tested using Eltro-1 stressed samples. [ABSTRACT FROM AUTHOR]

The aim of this work was the development of an efficient analytical method for the determination of bisoprolol and related substances in the finished drug product using HPLC/DAD. Different bonded phases (alkyl and phenyl) with variable pore sizes and column dimensions, temperatures, and mobile phases with variable pH and additives were tested. Experiments that included using Hypersil 3 BDS C18 100 × 4 mm, 3 m; Zorbax SB C18 150 × 4.6 mm, 3.5 m; Acquity UPLC BEH C18 50 × 2.1 mm, 1.7 m; and Xterra MS C18 100 × 4.6 mm, 3.5 m gave the best results when considering the separation and resolution of the tested analytes within a reasonable run time. The method using Xterra MS C18 100 × 4.6 mm, 3.5 m was validated as the most suitable when taking into account the mobile phase preparation and versatility, analysis time, and equipment maintenance. Validation parameters (linearity, accuracy, precision, selectivity) confirmed the method as suitable for its intended use. [ABSTRACT FROM AUTHOR]

Related substance is a test which quantitates impurities in formulation. This research paper presents a logical and scientific development & validation of analytical method for estimation of impurities of Lamivudine, Tenofovir disoproxil fumarate & Efavirenz in fixed dose tablet formulation. Estimation of impurities of Lamivudine, Tenofovir disoproxil fumarate & Efavirenz in fixed dose tablet formulation was conducted by RPHPLC. The separation was achieved under optimized chromatographic condition on an Inertsil ODS-3 150×4.6mm; 5μm column with mobile phase-A consist of 20mM acetate buffer pH-3.8±0.05: Methanol (95:5 %v/v) & mobile phase-B consist of 20mM acetate buffer pH-3.8±0.05: Methanol (5:95 %v/v) with gradient elution at a flow rate of 1.0 mL/min using 35°C column oven temperature with PDA detection at 260 nm. The method was validated as per ICH and USP guideline and the values were found to be within the limits. So, the proposed method was found to be simple, linear, accurate, precise, robust and specific. [ABSTRACT FROM AUTHOR]

The review justifies the need to validate the linearity, relative accuracy, and precision of Related Substances methods for detecting unidentified substances. Various approaches and methods for the estimation of linearity, precision, relative accuracy, and other validation characteristics for unidentified impurities are considered. The conditions necessary for the correct application of these approaches are discussed. The term "main unidentified impurities" is proposed and justified for assessing the validation results. Acceptance criteria, examples, and recommendations are provided. [ABSTRACT FROM AUTHOR]

A simple, rapid, sensitive, specific, eco-friendly and stability-indicating linear gradient liquid chromatographic method (RP-UHPLC) for simultaneous estimation of assay and its related compounds in Meropenem API samples is developed and validated. Chromatographic separation was achieved on Zorbax Eclipse plus C18, (100 x 4.6) mm, 3.5 µm RRLC short column and 10 mM potassium dihydrogen orthophosphate is used as buffer, buffer solution used as eluent A and buffer and acetonitrile combination 30: 70 v/v ratio used as eluent B and Agilent RRLC (UHPLC) system is used for analysis. The mobile phase flow rate was 1.0 ml/min, and the eluted compounds have been monitored at 220 nm for related substance method and 290 nm for assay method. Excellent resolution is obtained between Meropenem and its related compounds which were eluted within 10 min. The correlation co-efficient(r) is > 0.995 for both the methods from linearity data and percentage of recovery is 98.0 to 102.0 and 80.0 to 120.0% for assay method and for related substance method, respectively. Sensitivity of the method is found to be less than 0.316 µg/ml. Peak homogeneity data for Meropenem in the chromatograms from the stressed samples are obtained by using photodiode array detector demonstrated the specificity of the method for analysis of Meropenem in presence of the degradation compounds. The performance of the method is validated according to the present ICH guidelines for specificity, limit of detection, limit of quantification, linearity, accuracy, precision, and robustness. [ABSTRACT FROM AUTHOR]

Aim: In particular, the objective of this research work is related to treating patients in need of nonsteroidal anti-inflammatory therapy. The study was aimed to prepare topical administrations of dexibuprofen in the form of a transdermal gel so that the problems associated with oral administration of dexibuprofen are avoided. This present study is focused to study the stability profile for the prepared hydroalcoholic and hydrogels of dexibuprofen. Materials and Methods: The dexibuprofen hydroalcoholic and hydrogels were prepared by simple dispersion techniques. The prepared hydroalcoholic and hydrogels were subjected to stability under accelerated stability (40°C/75% RH) condition. The stability samples are withdrawn at predetermined time intervals, drug content and related substances were analyzed by the developed high-performance liquid chromatography technique. Results: There are observed highest unknown impurity in hydroalcoholic gel due to drug degradation. Hence, the optimized formulation G9 of hydroalcoholic gel was prepared with free from alcohol (hydrogel) to maintain the stability. The dexibuprofen hydrogel was not observed any significant unknown impurity; it can able to maintain the shelf life. Conclusion: Since an effort was made to formulate a stable transdermal gel, due to the related substances observed on the hydroalcoholic gel, alcohol free dexibuprofen hydrogel shows no change in the drug content and related substances. The results are encouraging the formulations of the hydrogel. [ABSTRACT FROM AUTHOR]

Modern research and development on medicine for various brain diseases, out of these diseases psychotic is the major problem, to overcome this problem scientist evolved medicine that is Risperidone. It is an antipsychotic drug. In this study, approached a new analytical method to determine the majority of impurities e.g. pharmacopeial [United state pharmacopeia], European pharmacopeia and non-pharmacopieal i.e. An abbreviated new drug application [ANDA]. Impurities of Risperidone analyzed by Ultra performance liquid chromatography. UPLC is advance techniques that give fast separation with a short period and have High pressure than HPLC with less consumption of solvents and buffers. This UPLC has many advantages for the analysis of drug products by using this concept achieved the separation of peaks of Resperidone impurities, so UPLC is very preeminent techniques for the analysis of API and drug products in pharmaceutical analysis.The waters UPLC system in the present research paper giving the best separations of total fourteen resperidone impurities as per the requirement of pharmacopeia. [ABSTRACT FROM AUTHOR]

In the present study, a reliable LC-QTOF-MS method was developed and employed for the separation and characterization of process-related substances and forced degradation products of Lurasidone hydrochloride. The chromatographic separation was carried out using an Agilent Poroshell 120 Bonus-RP C18 column (100 mm × 4.6 mm, 2.7 µm) and a mobile phase consisting of a gradient elution of 10 mM ammonium formate solution and methanol. The degradation studies followed the guidelines outlined in ICH Q1A (R2). It was observed that Lurasidone hydrochloride exhibited instability under photolytic, alkaline, and oxidative stress conditions, while remaining relatively stable under acidic and thermal stresses. Through positive ESI-QTOF mass spectrometric analysis, fourteen related compounds in total, including both process-related and stress degradation products, were identified based on the accurate masses of parent and product ions and calculated elemental compositions. Amongst these substances, nine had not been previously reported, and their formation mechanisms were speculated. The process-related substances were further confirmed by NMR spectra determination, and suggestions were proposed to eliminate them. This study highlights the potential for monitoring and controlling related substances during the manufacturing processes, providing valuable insights for process optimization and quality control of Lurasidone hydrochloride. • LC/QTOF/MS analysis was utilized to characterize both process-related substances and the degradants of Lurasidone. • A total of fourteen, including nine previously unreported lurasidone-related substances, were successfully identified. • The mass fragmentation pathways for Lurasidone and its related substances were accurately elucidated. • Strategies for monitoring and controlling manufacturing-related substances were suggested. [ABSTRACT FROM AUTHOR]

A novel HPLC method was developed and validated for the determination of cilnidipine (CLDP) along with its related impurities A and B in pharmaceutical formulations. The chromatographic separation was carried out by isocratic elution using an X Terra C18 column (250×4.6mm; 5µ). The mobile phase was composed of methanol and phosphate buffer at a pH of 5.8 in the ratio of 10:90 (V/V) at a flow rate of 1.0 mL/min. The eluents were detected and quantified at a UV detection wavelength of 229 nm. Calibration curves of all analytes in the range of 2-12µg/mL showed a good correlation linearly (r = 0.999) with recovery rate of more than 98% for each analyte. The percentage RSD in intraday, interday precision and ruggedness were found to be less than 2. Small variations in the developed conditions like mobile phase ratio, flow rate, pH and UV wavelength do not influence the results. This proves the precise and robust nature of the developed method. Stress degradation studies were conducted for standard drug and high amount of degradation was observed under UV light exposure. After 24hours, the molecules degraded up to 9.967%. In base hydrolysis, the CLDP molecule degrades up to 6.223%. In other stress conditions like acidic (5.347%), oxidative (4.916%) and thermal (4.319%) conditions, CLDP was found to be highly labile. In stress degradation study, there is no interference of both known impurities and other degradation products formed and were separated from CLDP. Therefore, this method was found to be selective and specific. The method development and validation result confirms that this method is suitable for determination and quantification of process impurities (A and B) of CLDP in pharmaceutical formulations. [ABSTRACT FROM AUTHOR]

A high-performance liquid chromatography method for the determination of dextromepromazine, levomepromazine sulfoxide and 2-methoxyphenothiazine in levomepromazine samples was developed. The separation of the analytes was achieved within 10 min on a stationary phase containing cellulose tris (4-methylbenzoate) as chiral selector. The mobile phase consisted of 0.1% diethylamine in methanol with a flow rate of 1.0 mL/min. The method was validated according to the International Council for Harmonization guideline Q2(R1). The detection limits based on a signal-to-noise ratio of 3 were in the range of 0.002 to 0.005 μg/mL. The method proved to be precise and accurate in the concentration range of 0.025–1.0 % for levomepromazine sulfoxide and 2-methoxyphenothiazine and 0.025% to 3.0% for dextromepromazine relative to a concentration of 0.1 mg/mL of levomepromazine, with the exception of levomepromazine sulfoxide at the 0.1% level. The method was subsequently applied to the analysis of finished pharmaceutical products as well as of reference substances of the European Pharmacopoeia. [ABSTRACT FROM AUTHOR]

Ten related substances in coenzyme A (CoA) were detected using a newly developed gradient reverse phase high performance liquid chromatographic (HPLC) method. A highly specific and efficient LC–MS/MS method was developed to characterize process-related substances and the major degradation products, and three unknown related substances were further synthesized and characterized by H-NMR and C-NMR spectroscopy. Synthesized samples of the related substances were used for quantitative analysis by HPLC. The method was validated according to ICH guidelines with respect to specificity, precision, accuracy and linearity. The forced degradation studies included acidic, alkaline, oxidative, photolytic and thermal stress conditions. Furthermore, we depicted and speculated the probable mechanism of formation of related substances and the plausible fragmentation mechanism showed that all the related substances came from the manufacturing process. Characterization, synthesis and quantitative analysis of related substances were discussed in detail, and were critical for quality control, manufacturing process optimization and CoA monitoring, all of which were important to ensure the security of CoA. [ABSTRACT FROM AUTHOR]

Capillary electromigration techniques have become important tools for the analysis of pharmaceutical drugs. The present review updates on recent developments of the analysis of small molecule drugs, excipients and counter ions dating between January 2014 and May 2017. Capillary electrophoresis (CE) continues to be a very popular method for the analysis of the active pharmaceutical ingredients and their related substances in pharmaceutical formulations, especially for the determination of the stereoisomeric purity of chiral drugs, which is evidenced by a large number of related literature reported in the reviewed period of time. The simultaneous analysis of several drugs has been easily achieved by CE. Moreover, the flexibility of the technique has been clearly illustrated by the application of various separation modes including capillary zone electrophoresis, isotachophoresis as well as various modes of electrokinetic chromatography such as micellar electrokinetic chromatography or microemulsion electrokinetic chromatography in combination with various detection modes including direct and indirect UV, laser-induced fluorescence, mass spectrometry and contactless conductivity detection. A general trend also observed in other analytical techniques is the application of quality by design principles in CE. [ABSTRACT FROM AUTHOR]

Using a quality by design approach, a capillary electrophoresis method for the simultaneous determination of dextromepromazine and the oxidation product levomepromazine sulfoxide in levomepromazine was developed. The analytical target profile was defined that the method should be able to quantify 0.1% of both impurities with a precision of  ≤10%. Hydroxypropyl-γ-cyclodextrin was used as chiral selector. The critical process parameters cyclodextrin concentration, buffer pH and concentration as well as temperature and applied voltage were studied using a fractional factorial resolution V+ design for defining the knowledge space. A central composite face centered design was used as response surface methodology for deriving the design space by Monte Carlo simulations. The selected working point was a 100 mM citric acid buffer, pH 2.85, containing 3.6 mg/mL hydroxypropyl-γ-cyclodextrin, a temperature of 15 °C and a voltage of 25 kV. Robustness was estimated using a Plackett-Burman design. The method was subsequently validated in the relative concentration range of 0.1%–1.0% of the impurities for a solution containing 0.25 mg/mL levomepromazine. The method was applied to the determination of the purity of the reference substance of the European Pharmacopoeia and of the drug in a commercial injection solution. [ABSTRACT FROM AUTHOR]

This study aims at investigating the separation, identification and characterization of related substances in apremilast by LC–MS hyphenated techniques, as well as the synthesis optimization and the degradation pathways elucidation. Forced degradation studies were conducted under the ICH prescribed stress conditions. The chromatographic separation was achieved on XBridge C18 column (4.6mm × 150 mm, 3.5 μm) using a mobile phase consisting of water adjusted to pH 3.0 with formic acid as solvent A and acetonitrile as solvent B in linear gradient elution program. Twelve related substances were detected all together in apremilast and its stress samples. Their structures were identified mainly through positive ESI high-resolution TOF-MS analysis of the parent ions' accurate masses and elemental compositions, and the corresponding MS/MS spectra elucidation. There were three process-related substances and nine degradation products, seven of them were first reported. Two degradation products and one process-related substance were further verified by semi-preparation and NMR determination. Their origins and formation mechanisms were also discussed, based on which effective approaches for the synthesis optimization were conducted. Therefore, the related substances investigation are valuable for apremilast manufacturing process optimization and quality control. [ABSTRACT FROM AUTHOR]

Pidotimod (3-L-pyroglutamyl-L-thiaziolidine-4 carboxylic acid) is a synthetic dipeptide molecule with immunomodulatory properties. Since the early 90's, a wide scientific production has been published about it. As it's effective in the treatment of people infected with bacteria and viruses, it is used in the treatment of repeated infections of the respiratory, urogenital, and ear, nose, throat systems. Pidotimod therapy is a reliable, simple, and safe approach to treat children with recurrent respiratory infections. Liquid chromatography-mass spectrometry (LC/MS) method has been used for determination of pidotimod in different biological matrices. Only a few HPLC-UV methods have been reported for the quantification of the related substances in pidotimod and its formulation. The reported LC/MS methods usually use formic acid or acetic acid in the mobile phase which are not suitable for UV detector, and the separation is not feasible for the related substances. And the reported HPLC-UV methods usually use phosphate and phosphoric acid in the mobile phase which are not suitable for mass spectrometry detector. However, there is no reliable LC/MS method for identification of the related substances in pidotimod. In this paper, a LC/MS method was developed for the separation and characterization of process related substances and the major degradation products in pidotimod. Electrospray positive ionization high resolution time-of-flight mass spectrometer (ESI-TOF MS) was used for the determination of the accurate mass and elemental composition of the parent ions of the related substances, and triple quadrupole tandem mass was employed for the product mass spectra determination. The separation was performed on a Sepax GP-C8 column (250 mm×4.6 mm×5 μm) using 0.005% trifluoroacetic acid (TFA) in water as mobile phase A and methanol as mobile phase B. The flow rate was 1.0 mL/min and the column temperature was set at 30 ℃. Analytes were monitored at 210 nm. The injection volume was 20 μL. Pidotimod was tending to degrade under acid, alkaline, oxidative, thermal stress and photolytic stress. The structures of the related substances were then figured out through elucidation of the fragment ions. A total of 11 related substances were detected and characterized, including process related substances (related substances 1 and 4) and degradation products. Related substances 4 and 10 were identified by synthetic reference and related substances 1, 2, 8 and 9 were reported before this study, while related substances 3, 5, 6, 7 and 11 were reported for the first time. The method is effective for separation and identification of the related substances of pidotimod, and the results are useful for the quality control and process optimization of pidotimod. [ABSTRACT FROM AUTHOR]

Antibacterial combinations consisting of the semisynthetic antibiotic amoxicillin (amox) and the β-lactamase inhibitor potassium clavulanate (clav) are commonly used and several chromatographic methods were reported for their quantification in mixtures. In the present work, single HPLC method for related substances analyses of amoxicillin and potassium clavulanate mixtures was developed and validated according to international conference on harmonization (ICH) guidelines. Eighteen amoxicillin and six potassium clavulanate impurities were successfully separated from each other by using triple gradient elution using a Thermo Hypersil Zorbax BDS C18 (250 mm × 4.6 mm, 3 μm) column with 50 μL injection volumes at a wavelength of 215 nm. Commercially unavailable impurities were formed by degradation of amoxicillin and potassium clavulanate, identified by LC–MS studies and used during analytical method development and validation studies. Also, process related amoxicillin impurity-P was synthesized and characterized by using nuclear magnetic resonance (NMR) and mass spectroscopy (MS) for the first time. As complementary of this work, an assay method for amoxicillin and potassium clavulanate mixtures was developed and validated; stress-testing and stability studies of amox/clav mixtures was carried out under specified conditions according to ICH and analyzed by using validated stability-indicating assay and related substances methods. [ABSTRACT FROM AUTHOR]

Azilsartan Kamedoxomil is an AT1-subtype angiotensin II receptor blocker (ARB). During the laboratory synthesis of Azilsartan Kamedoxomil, four related substances of Azilsartan Kamedoxomil were observed and identified. These were 2-Ethoxy-3-[[4-[2- [4-[(5-methyl-2-oxo-1,3-dioxol-4-yl)methyl]-5-oxo-1,2,4-oxadiazol-3-yl]phenyl]phenyl] methyl] benzimidazole-4-carboxylic acid (azilsartan N-medoxomil, 9), (5-methyl-2-oxo- 1,3-dioxol-4-yl)methyl 2-ethoxy-3-[[4-[2-[4-[(5-methyl-2-oxo-1,3-dioxol-4-yl)methyl]-5- oxo-1,2,4-oxadiazol-3-yl]phenyl]phenyl] methyl] benzimidazole-4-carboxylate (azilsartan dimedoxomil, 10), (5-methyl-2-oxo-1,3-dioxo-4-yl)methyl 1-[2'-(4,5-dihydro-5-oxo-4H- 1,2,4-oxadiazol-3-yl)biphenyl-4-yl]methyl]-2-methoxy-1H-benzimidazole-7-carboxylate (methoxy analogue of azilsartan medoxomil, 11), Methyl 1-((2'-amidobiphenyl-4-yl) methyl)-2-ethoxy-1H-benzo[d]imidazole-7-carboxylate (amide methyl ester, 12). The present work describes the origin, synthesis and characterization of these related substances. [ABSTRACT FROM AUTHOR]

Ursodeoxycholic acid has gained increasing attention due to its recent discovery of the preventive effect on SARS-CoV-2 infection. Ursodeoxycholic acid has been included in various pharmacopoeias as an old drug, and the latest European Pharmacopoeia lists nine potential related substances (impurities A∼I). However, existing methods in pharmacopoeias and literature can only quantify up to five of these impurities simultaneously, and the sensitivity is inadequate, as the impurities are isomers or cholic acid analogues lacking chromophores. Herein, a novel gradient RP-HPLC method coupled to charged aerosol detection (CAD) was developed and validated for the simultaneous separation and quantification of the nine impurities in ursodeoxycholic acid. The method proved sensitive and allowed the quantification of the impurities as low as 0.02 %. Relative correction factors of the nine impurities were all within the range of 0.8–1.2 in the gradient mode by optimizing chromatographic conditions and CAD parameters. In addition, this RP-HPLC method is fully compatible with LC-MS due to the volatile additives and high percentage of the organic phase, which can be directly used for the identification of impurities. The newly developed HPLC-CAD method was successfully applied to commercial bulk drug samples, and two unknown impurities were identified by HPLC-Q-TOF-MS. The effect of CAD parameters on the linearity and correction factors was also discussed in this study. Overall, the established HPLC-CAD method can improve the methods in current pharmacopoeias and literature and contributes to understanding the impurity profile for process improvement. [Display omitted] • Separation of all nine specified impurities of ursodiol by a single method. • HPLC with charged aerosol detector to detect impurities for lack of chromophores. • Method proved sensitive and correction factors of nine impurities were all 0.8–1.2. • Method is compatible with LC-MS and two unknown impurities were identified. • Overcoming the deficiency of existing methods in pharmacopoeias and literature. [ABSTRACT FROM AUTHOR]

Objective To establish a HPLC method for the assay of cyproheptadine hydrochloride and the related substances. Methods The HPLC was performed on an Agilent Eclipse XDB-C18column (4. 6 mm × 250 mm, 5 μm) at the temperature of 25 °C with the mobile phase of acetonitrile-buffer Solution ( Dissolve 2. 16 g of sodium octane-1-sulfonate with about 500 ml of water and mix well. Add 10. 0 ml of glacial acetic acid and 5. 0 ml of triethylamine, and dilute with water to 1 000 ml, mix well and adjust to pH 7. 0 with triethylamine) (85 : 15, V/V). The flow rate was 1. 0 ml/min and detection wavelength was 286 nm. The injection volume was 10 μl. Results The calibration curves of cyproheptadine hydrochloride, impurity A, B and C showed good linear response in the range from 0. 056 2 to 5. 620 μg/ml (r = 0. 999 8), 0. 052 4 to 5.240 μg/ml(r=1.000 0),0.050 3 to 5.032 μg/ml (r=0. 999 9) and 0. 053 2 to 5. 316 μg/ml(r=0. 999 8) respectively. The LOQs for cyproheptadine hydrochloride, impurity A, B and C were within 0. 049-0. 054 μg/ml, LODs were within 0.019-0.022 μg/ml with recovery between 98%-100%. RSD of repeatability was 5. 5% (n=6). Conclusion This method gave an accurate and reliable results. It can be used for quality control of cyproheptadine hydrochloride. [ABSTRACT FROM AUTHOR]

A highly specific and efficient LC-QTOF mass spectrometric method was developed for the separation and characterization of process related substances and the major degradation products in alogliptin benzoate and its tablets. The separation was performed on Phenomenex Gemini-NX C 18 column (250 mm × 4.6 mm, 5 μm) using 0.2% formic acid-0.2% ammonium acetate in water as mobile phase A, acetonitrile and methanol (60:40, v/v) as mobile phase B in linear gradient elution mode. Forced degradation studies were also conducted under ICH prescribed stress conditions. Alogliptin benzoate and its tablets were tending to degrade under acid, alkaline, oxidative and thermal stresses, while relatively stable to photolytic stress. A total of seven related substances were detected and characterized through liquid chromatography-high resolution QTOF mass spectrometry techniques, including process related substances and degradation products, and two of them were further synthesized and characterized by NMR spectroscopy. Based on the related substances elucidation and the plausible formation mechanisms, efficient approaches were proposed to reduce or eliminate related substances, and in consequence the quality of alogliptin benzoate and its tablets have been promoted obviously. Therefore, the impurity profiles obtained are critical to the quality control and manufacturing processes optimization and monitoring of alogliptin benzoate and its tablets. [ABSTRACT FROM AUTHOR]

Aceclofenac is a phenyl aceticacid derivative with potent analgesic and anti inflammatory properties and an improved gastro intestinal tolerance. In the present study, a Reverse Phase HPLC method and FTIR methods were developed for the analysis of Aceclofenac for related substances and concordance with the standard. Both the methods showed excellent sensitivity with 0.008% total impurities and the sample spectrum is 99.89% concordant with that of standard aceclofenac .This sensitive and selective method can be used for detection of related substances in aceclofenac in order to control and regulate process related impurities. [ABSTRACT FROM AUTHOR]

The objective of the current study was to develop and validate a sensitive and specific LC–MS compatible stability indicating reversed phase liquid chromatographic method for the quantitative determination of Gabapentin and its related substances using Corona charged aerosol detection (CAD). The chromatographic conditions were optimized using a Kinetix Biphenyl column with gradient elution using a mobile phase composed of pH 4.2 ammonium acetate, acetonitrile, and methanol. Forced degradation was observed in basic and peroxide conditions and the major degradants were identified by LC–MS/MS analysis. The developed RP-HPLC CAD method was validated according to ICH guidelines. The LOD and LOQ values for Gabapentin and all its related impurities ranged from 0.075 μg/mL to 0.18 μg/mL and 0.25 μg/mL to 0.60 μg/mL, respectively. The recovery for all impurities ranged from 91.0 to 105.6%w/w. Solutions were stable for 7 days at room temperature. The validated method produced acceptable precision, linearity, accuracy, robustness and ruggedness. [ABSTRACT FROM AUTHOR]