Development of forced degradation and stability indicating studies of drugs-A review

Analysis of omarigliptin forced degradation products by ultra-fast liquid chromatography, mass spectrometry, and in vitro toxicity assay

Omarigliptin (OMG) is an antidiabetic drug indicated for the treatment of type 2 diabetes mellitus. Forced degradation studies are practical experiments to evaluate the stability of drugs and to establish degradation profiles. Herein, we present the investigation of the degradation products (DPs) of OMG formed under various stress conditions. OMG was subjected to hydrolytic (alkaline and acidic), oxidative, thermal, and photolytic forced degradation. A stability-indicating ultra-fast liquid chromatography method was applied to separate and quantify OMG and its DPs. Five DPs were adequately separated and detected in less than 6 min, while other published methods detected four DPs. MS was applied to identify and obtain information on the structural elucidation of the DPs. Three m/z DPs confirmed previously published research, and two novel DPs were described in this paper. The toxicity of OMG and its DPs were investigated for the first time using in vitro cytotoxicity assays, and the sample under oxidative conditions presented significant cytotoxicity. Based on the results from forced degradation studies, OMG was found to be labile to hydrolysis, oxidation, photolytic, and thermal stress conditions. The results of this study contribute to the quality control and stability profile of OMG.

A Quality by Design (QbD) driven gradient high performance liquid chromatography method development for the simultaneous estimation of dasatinib and nilotinib in lipid nanocarriers

Tyrosine kinase inhibitors (TKIs) are effective as a targeted treatment for chronic myeloid leukemia (CML), which can selectively suppress BCR-ABL1 kinase activity. CML therapy with TKIs combination has been supported by in-vitro, in-vivo, and patient-based data where the nilotinib-dasatinib co-administration has exerted superior anticancer efficacy with greater cellular uptake, less resistance to chemotherapy, and no additive adverse events encountered. Therefore, it is essential to develop a suitable analytical method for the simultaneous estimation of these drugs in the developed novel lipid nanocarriers like liposomes. Design of Experiment (DoE) has been implemented as a tool of QbD to systematically investigate the relation between the HPLC method attributes and analytical responses, i.e., chromatographic detection, quantification, and peak properties for dasatinib and nilotinib. An Ishikawa diagram is constructed to delineate possible influencing variables to the analytical performances. Afterward, 4 factors 2 level full factorial design (FFD) was employed to model and identify the main effects and interaction effects between the factors selected after the initial risk assessment. The suggested design space for optimized chromatographic conditions by QbD analysis is linear within the selected range of drug concentrations, accurate and precise, sensitive, and robust according to the ICH guidelines. The optimal method is comprised of a 1 mL/min flow rate of mobile phase (ACN and 20 mM KH2PO4 of pH 7.00) in gradient mode at 25 °C column temperature for 20 μL sample injection volume and detection wavelength fixed at 297 nm. Most importantly, this novel HPLC method is simple and selective enough to evaluate dasatinib and nilotinib content in the lipid nanocarriers.

The Metabolism and Disposition of Brepocitinib in Humans and Characterization of the Formation Mechanism of an Aminopyridine Metabolite

Brepocitinib is an oral once-daily Janus kinase 1 and Tyrosine kinase 2 selective inhibitor currently in development for the treatment of several autoimmune disorders. Mass balance and metabolic profiles were determined using accelerator mass spectrometry in six healthy male participants following a single oral 60 mg dose of 14C-brepocitinib (∼300 nCi). The average mass balance recovery was 96.7% ± 6.3%, with the majority of dose (88.0% ± 8.0%) recovered in urine and 8.7% ± 2.1% of the dose recovered in feces. Absorption of brepocitinib was rapid, with maximal plasma concentrations of total radioactivity and brepocitinib achieved within 0.5 hours after dosing. Circulating radioactivity consisted primarily of brepocitinib (47.8%) and metabolite M1 (37.1%) derived from hydroxylation at the C5' position of the pyrazole ring. Fractional contributions to metabolism via cytochrome P450 enzymes were determined to be 0.77 for CYP3A4/5 and 0.14 for CYP1A2 based on phenotyping studies in human liver microsomes. However, additional clinical studies are required to understand the potential contribution of CYP1A1. Approximately 83% of the dose was eliminated as N-methylpyrazolyl oxidative metabolites, with 52.1% of the dose excreted as M1 alone. Notably, M1 was not observed as a circulating metabolite in earlier metabolic profiling of human plasma from a multiple ascending dose study with unlabeled brepocitinib. Mechanistic studies revealed that M1 was highly unstable in human plasma and phosphate buffer, undergoing chemical oxidation leading to loss of the 5-hydroxy-1-methylpyrazole moiety and formation of aminopyrimidine cleavage product M2. Time-dependent inhibition and trapping studies with M1 yielded insights into the mechanism of this unusual and unexpected instability. SIGNIFICANCE STATEMENT: This study provides a detailed understanding of the disposition and metabolism of brepocitinib, a JAK1/TYK2 inhibitor for atopic dermatitis, in humans as well as characterization of clearance pathways and pharmacokinetics of brepocitinib and its metabolites.

A design of experiment based RP-HPLC method for the simultaneous estimation of antihypertensive drugs with greenness assessment

The correlation between blood pressure (BP) and cardiovascular risk has a continuous, positive, and linear pattern. Lowering high BP decreases the risk associated with cardiovascular disease. Chlorthalidone (CHD) and Losartan potassium (LOS) combination is used to treat hypertension. The analytical community was concerned with minimizing or reducing the use of toxic chemicals and solvents. Therefore, the current study aimed to develop a rapid, sensitive, and cost-effective green RP-HPLC method to determine CHD and LOS simultaneously in a short analysis of time. Method optimization was performed by Central composite design (CCD), the flow rate and the change of time were chosen as factors. Effective separation was conducted on Zorbax SB-C18 (4.6 mm × 150 mm, 5 μm) column by gradient mobile phase comprising phosphate buffer and ethanol flowing at 0.859 ml/min, and the wavelength detected at 230 nm. As per ICH criteria, the technique was proven to be precise, accurate, and linear over the concentration range of 4.3-8.1 μg/ml for CHD and 35-65 μg/ml for LOS. Furthermore, the method's greenness was examined by three different metrics, confirming that less toxic effect on the environment. Hence, the optimized approach proves to be eco-friendly, simple, and robust for the concurrent evaluation of CHD and LOS in pharmaceutical formulations.

Identification and Characterization of Rotigotine Degradation Products by HPLC Coupled DAD and CAD Detectors and HRMS Through Q-Orbitrap and Electrospray Ionization

Rotigotine (RTG) is a dopamine agonist used in the treatment of Parkinson's disease. As it is susceptible to oxidation, stability studies must be carefully designed for the identification and characterization of all possible degradation products. Here, RTG degradation was evaluated according to the International Conference on Harmonization guidelines under various stress conditions, including acidic and basic hydrolysis, oxidative, metallic, photolytic, and thermal conditions. Additionally, more severe stress conditions were applied to induce RTG degradation. Significant degradation was only observed under oxidative and photolytic conditions. The samples were analyzed by high performance liquid chromatography coupled to photodiode array detectors, charged aerosol, and high-resolution mass spectrometry. Chromatographic analyses revealed the presence of eight substances related to RTG, four of which were already described and were qualified impurities (impurities B, C, K and E) and four new degradation products (DP-1 - DP-4), whose structures were characterized by high-resolution mass spectrometry through Q-Orbitrap and electrospray ionization. In the stress testing of the active pharmaceutical ingredient in solid form, significant RTG degradation was observed in the presence of the oxidative matrix. The results corroborate the literature that confirm the high susceptibility of RTG to oxidation and the importance of using different detectors to detect degradation products in forced degradation studies.

A stability indicating RP-HPLC-UV assay method for the simultaneous determination of hydroquinone, tretinoin, hydrocortisone, butylated hydroxytoluene and parabens in pharmaceutical creams

Multicomponent drugs are medications that combine two or more active pharmaceutical ingredients in a single dosage form. These dosage forms improve the patient compliance, reduce the risk of drug interactions, and simplify dosing regimens. However, quality control of these multicomponent dosage forms can be challenging, especially if the final product contains four or more ingredients that are active (comprise stabilizers, preservatives, excipients, and other components). This problem can be more pronounced if the excipients can interfere with the analysis. In this work, a stability indicating assay method was developed and validated (according to the ICH International Guidelines) for the simultaneous determination of hydroquinone (HQ), tretinoin (TRT), hydrocortisone (HCA), butylated hydroxytoluene (BHT), methyl paraben (MP) and propyl paraben (PP) in commercially available pharmaceutical creams. The proposed method is based on gradient elution using X-Bridge C18 (150 × 4.6 mm, 5 µm) column with a flow rate of 1 mL/min. The linear ranges (μg/mL) were 240-560 for HQ, 24-56 for MP, 132-308 for HCA, 6-14 for PP, 12-28 for BHT, 6.6-15 for TRT. During the validation process, the intra- and interday precision and trueness (evaluated as recovery) were found to be below 2.0% and between 100-102%, respectively. System suitability tests (SST) allow validating the herein proposed procedure specifically for pharmaceutical and industrial applications. SST test shows that the reported procedure fulfill with the Guidelines, allowing excellent separation of the analytes with very sensitive, accurate (precise and true) and reproducible quantitation of each analytes. The method was successfully applied in forced degradation studies of the six analytes. Specifically, acid degradation slightly affected HCA and BHT (91% recovery), while alkaline degradation drastically reduced HCA recovery (5.5%) and moderately affected BHT (85%). Photodegradation primarily influenced TRT quantity, and oxidative degradation intensified the BHT peak (130%).

QbD-Based Stability-Indicating RP-HPLC Method Development and Validation for the Estimation of Favipiravir-An Eco-Friendly Approach

BACKGROUND

Analytical quality by design (AQbD) affords a systematic scaffolding to triumph a continuously validated, robust assay as well as life cycle management. The resuscitative repurposed drug favipiravir, an oral drug approved for reemerging pandemic influenza in Japan in 2014, is used for the treatment of life-threatening pathogens such as Ebola, Lassa virus, and currently COVID-19. Favipiravir is gaining a great deal of medical importance due to its pharmaceutical applications.

OBJECTIVE

To develop and validate a risk-based stability-indicating RP-HPLC method employing an AQbD approach using Central Composite Design (Design Expert Software 13.0) for the estimation of favipiravir.

METHOD

The Quality Target Product Profile optimized were flow rate and mobile phase composition, thus assessing the critical analytical attributes (retention time, tailing factor, and number of theoretical plates) as the constraints of method robustness. The proposed technique was optimized with a C18 (150 × 4.6 mm, 5 µm) column and 0.1% orthophosphoric acid buffer-acetonitrile (50:50, v/v) as the mobile phase at a flow rate of 1 mL/min using diode-array detector (230 nm) eluted favipiravir at 2.3 min.

RESULTS

The optimized method validated as per ICH guideline Q2 (R1) was found to be eco-friendly, simple, precise (RSD 0.0051-1.2%), accurate (99.86-100.22%), linear (25-150 µg/mL), rugged (RSD 0.70%), and robust (RSD 0.6-1.6%) with a limit of detection and limit of quantitation of 1.140 µg/mL and 4.424 µg/mL, respectively.

CONCLUSION

Forced degradation studies (acidic, alkaline, thermal, photolytic, and oxidative conditions) revealed the suitability of the AQbD method for the analysis of favipiravir in tablet formulation.The developed and validated AQbD method is less time consuming and can be used in the industry for routine quality control/analysis of bulk drug and marketed Favipiravir products.

HIGHLIGHTS

A robust Design of Experiment enhanced stability-indicating analytical method was developed and validated for the estimation of favipiravir. Furthermore, the contemporary method would aid in extending the analysis of favipiravir in other formulations.

A Robust HPLC Approach for Quantitation of Camptothecin in Mesoporous Silica Nanoparticles Matrix and in the Presence of Its Degradation Products

BACKGROUND

Camptothecin is a potent anticancer drug used for the treatment of various cancers.

OBJECTIVE

The goal of this research investigation was to develop and validate a new stability-indicating HPLC technique for the quantitative assessment of camptothecin in in-house developed mesoporous silica nanoparticles, a novel nanoformulation matrix for the treatment of cancer.

METHOD

The Waters Inertsil® HPLC column (C18) was used for the chromatographic separation, with a flow rate of 1 mL/min, a column oven temperature of 40°C, an injection volume of 10 µL, a detection wavelength of 216 nm, and a 10 min runtime overall. An isocratic blend of phosphate buffer (10 mM, pH7.0) and acetonitrile (60:40, v/v) served as the mobile phase. Various stress conditions including acid, alkali, oxidative, photolytic, thermal, and humidity environments were tested for the quantitative estimation of the camptothecin through the proposed method.

RESULTS

The results demonstrated that the proposed method is specific (peak purity ≥0.999), accurate (99.69-100.64% w/w), precise (RSD, % <2.0), and sensitive (LOD-0.17 µg and LOQ-0.56 µg) in accordance with ICH guideline Q2 (R1). Any unidentified degradation products did not interfere with the drug's estimation. Furthermore, the current method of analysis has eliminated any excipient interference from the matrix effect caused by the numerous excipients of the formulation matrix.

CONCLUSIONS

To quantify camptothecin for routine assay purposes, this research work offers a novel and straightforward HPLC methodology with optimized chromatographic parameters, contributing to the research and development community while ensuring an appropriate and efficient use of the drug through a variety of nanoformulation for cancer treatment.

HIGHLIGHTS

The stability-indicating HPLC method was found to be specific and suitable for routine analysis of camptothecin. The absence of any interference from excipients was confirmed by forced degradation studies.

Current Applications of Multivariate Curve Resolution-Alternating Least Squares (MCR-ALS) in Pharmaceutical Analysis: Review

The present review encompasses various applications of multivariate curve resolution- alternating least squares (MCR-ALS) as a promising data handling, which is issued by analytical techniques in pharmaceutics. It involves different sections starting from a concise theory of MCR-ALS and four detailed applications in drugs analysis. Dissolution, stability, polymorphism, and quantification are the main four detailed applications. The data generated by analytical techniques associated with MCR-ALS deals accurately with different challenges compared to other chemometric tools. For each reviewed purpose, it was explained how MCR-ALS was applied and detailed information was given. Different approaches were introduced to overcome challenges that limit the use of MCR-ALS efficiently in pharmaceutical mixture were also discussed.

An Overview of Degradation Strategies for Amitriptyline

Antidepressant drugs play a crucial role in the treatment of mental health disorders, but their efficacy and safety can be compromised by drug degradation. Recent reports point to several drugs found in concentrations ranging from the limit of detection (LOD) to hundreds of ng/L in wastewater plants around the globe; hence, antidepressants can be considered emerging pollutants with potential consequences for human health and wellbeing. Understanding and implementing effective degradation strategies are essential not only to ensure the stability and potency of these medications but also for their safe disposal in line with current environment remediation goals. This review provides an overview of degradation pathways for amitriptyline, a typical tricyclic antidepressant drug, by exploring chemical routes such as oxidation, hydrolysis, and photodegradation. Connex issues such as stability-enhancing approaches through formulation and packaging considerations, regulatory guidelines, and quality control measures are also briefly noted. Specific case studies of amitriptyline degradation pathways forecast the future perspectives and challenges in this field, helping researchers and pharmaceutical manufacturers to provide guidelines for the most effective degradation pathways employed for minimal environmental impact.

Determination of Related Substances in Promethazine Hydrochloride and Dextromethorphan Hydrobromide in Oral Solution by RP-HPLC Method

The goal of this study is to provide a single, widely applicable high-performance liquid chromatographic (HPLC) technique for the determination of related substances in multicomponent oral solution of promethazine hydrochloride and dextromethorphan hydrobromide. For the assessment of impurities of promethazine hydrochloride and dextromethorphan hydrobromide in oral solution, a unique, sensitive, quick, stability-indicating gradient HPLC technique has been created. For chromatographic separation, an Agilent Eclipse XDB-C18, 250 mm × 4.6 mm, 5 μm column was used with a buffered mobile phase consisting of a mixture of potassium dihydrogen phosphate pH 3.0:acetonitrile (80:20) v/v as mobile phase A and potassium dihydrogen phosphate pH 3.0:acetonitrile:methanol (10:10:80) v/v/v as mobile phase B. The separation was performed at a flow rate of 1.2 mL/min and a detection wavelength of 224 nm. The temperature of the column oven was regulated at 40°C. With good sensitivity and resolution, all compounds were effectively separated on a reverse-phase HPLC column. Acid, base, photolytic, thermal, oxidative and humidity stress conditions significantly degraded dextromethorphan hydrobromide and promethazine hydrochloride. The developed technique was validated according to the criteria of the International Conference on Harmonization for all validation parameters such as specificity, accuracy, linearity, precision, the limit of detection, the limit of quantitation and robustness.

Validation of an Ion-Pair Reverse Phase High-Performance Liquid Chromatography Method for the Detection of Major Components and Related Substances in Diquafosol Sodium Eye Drops

A simple, feasible, isocratic elution, and stable reversed-phase high performance liquid chromatography method was established and verified. The chromatographic conditions are as follows: EF-C18H, 4.6 × 250 mm, 5 μm column; column temperature 30 °C; for the mobile phase 27.2 g of KH2PO4 and 8.5 g of tetrabutylammonium hydrogen sulfate were taken, 2500 mL of water was added to dissolve, and the pH was adjusted to 6.7 with phosphoric acid:methanol solution with a ratio of 84:16 (V:V). The flow rate was 1.0 mL/min; the injection volume was 10 μL; and the wavelength was 262 nm. According to the current ICH guidelines, the developed method was verified, and the system suitability, specificity, LOD, LOQ, linearity, range, accuracy, repeatability, durability, and solution stability of the proposed method were verified. The validation results demonstrated that the LOQ for the method was 0.05% and the LOD was 0.02%. The content was detected within the concentration range of 300 to 900 μg/mL. The relationship between concentration and measurement was linear, with an r2 of >0.999. The concentration of impurities ranged from 0.3 to 4.5 μg/mL. A good linear correlation was observed within the range of g/mL, with a coefficient of determination r2 greater than 0.999. The accuracy and repeatability met the specified criteria.

Simultaneous quantification of 4-hydroxytamoxifen and hesperidin in liposomal formulations: Development and validation of a RP-HPLC method

Breast cancer treatment options are diverse, with tamoxifen commonly used as a selective estrogen receptor modulator (SERM) for hormone receptor-positive breast cancer. However, tamoxifen can have adverse systemic effects. Local transdermal therapy offers a potential solution by delivering the drug directly to the breast and minimizing systemic exposure. Hesperidin, a flavonoid, exerts synergistic effects when combined with anticancer agents. This combination therapy may be a more effective approach to breast cancer management. Analytical methods have been developed to quantify 4-Hydroxytamoxifen (4-HT) and hesperidin separately; however, no method currently exists for their simultaneous quantification in pharmaceutical formulations. This study aimed to develop and validate a reverse-phase high-performance liquid chromatography (RP-HPLC) method for the simultaneous quantification of 4-HT and hesperidin in liposomal formulations. A Design of Experiments (DoE) approach was employed using a Box-Behnken design (BBD) to optimize the RP-HPLC method. BBD allowed for a reduction in the number of required tests by creating a statistical model to estimate the significance of various factors and interactions. The methanol concentration, flow rate, and injection volume were considered as independent variables for optimization. A mobile phase (90:10 ratio of methanol: 0.1% v/v orthophosphoric acid) with a flow rate of 0.4 mL/min, and an injection volume of 10 μL was selected as optimized chromatographic condition. 4-HT showed a retention time (Rt) of 5.05 min and hesperidin showed an Rt of 7.11 min using an optimized analytical method and was detected at 275 nm. The developed RP-HPLC method was validated according to the International Council for Harmonization of Technical Requirements for Pharmaceuticals for Human Use (ICH) guidelines, confirming its accuracy, precision, linearity, selectivity, and robustness. The validated method was then successfully applied to determine the entrapment efficiency and permeation of 4-HT and hesperidin into loaded liposomes. This study fills a gap in the literature by providing a simple and reliable RP-HPLC method for the simultaneous quantification of 4-HT and hesperidin in liposomal formulations.

Identification and Structural Characterization of Degradation Products of Linagliptin by Mass Spectrometry Techniques

As part of the development and production of pharmaceuticals, the purity of Active Pharmaceutical Ingredients stands as a fundamental parameter that significantly influences the quality, safety, and efficacy of the final drug product. Impurities in Active Pharmaceutical Ingredients are various unwanted substances that can appear during the whole manufacturing process, from raw materials to the final product. These impurities can stem from multiple sources, including starting materials, intermediates, reagents, solvents, and even degradation products resulting from exposure to environmental factors such as heat, light, or moisture. Their presence can potentially compromise the therapeutic effect of the drug, introduce unexpected side effects, or even pose safety risks to patients. This study aims to conduct the forced degradation of linagliptin and subsequently attempt to identify the resulting degradants. The degradation procedures were carried out in accordance with the guidelines of the International Committee for Harmonization. The degradation profile of linagliptin was investigated under various conditions, including acid hydrolysis, alkaline hydrolysis, oxidation, heat, and light exposure, utilizing ultra-performance liquid chromatography connected to a photo array detector. Identification and characterization of the degradation products were achieved using an ultra-performance liquid chromatography coupled with a single quadrupole detector mass spectrometer and also a liquid chromatography coupled with a high-resolution mass spectrometry. The identified degradation products demonstrate that linagliptin is particularly susceptible to degradation when exposed to acid and peroxide. Whereas, no significant degradation effects were observed under alkali, thermolytic, and photolytic conditions.

The Development of a Stable Peptide-Loaded Long-Acting Injection Formulation through a Comprehensive Understanding of Peptide Degradation Mechanisms: A QbD-Based Approach

Quality by design (QbD) serves as a systematic approach to pharmaceutical development, beginning with predefined objectives and emphasizing an understanding of the product based on sound science and risk management. The purpose of this study is to utilize the QbD concept to develop a stable peptide-loaded long-acting injection formulation. An in-depth comprehension of peptide degradation mechanisms was achieved through forced degradation investigations, elucidating (acid) hydrolysis and oxidation as the primary degradation pathways for the peptide ACTY116. The quality built into the product was focused on risk assessment, for which the critical material attributes (CMAs) and critical process parameters (CPPs) associated with the critical quality attributes (CQAs) of each formulation were identified, leading to the development of the corresponding control strategies. CQAs for three LAI (long-acting injectable) formulations were enhanced by taking the right control strategies. The LAI formulation exhibiting the highest stability for ACTY116 was chosen for subsequent pharmacokinetic investigations in rats. The objective of addressing peptide chemical instability and in vivo long-acting release was achieved. For other molecules with susceptible functionalities like amide bonds, amino groups, and hydroxyl groups, the utilization of PLGA-based in situ gel as an LAI formulation for stabilizing molecules provides valuable insights.

Structural Elucidation of Novel Degradation Impurities of Ibrutinib in Ibrutinib Tablets Using Preparative Chromatography, LCMS, HRMS and 2D NMR Techniques

Ibrutinib is an orally administered compound that functions as an irreversible covalent inhibitor of the Bruton tyrosine kinase, an essential element in multiple cellular processes including B-cell differentiation, proliferation, migration, survival and apoptosis. The compound has been found to demonstrate efficacy against a range of B-cell malignancies. The drug product is available in oral tablet and capsule formulations. The drug degradation profiles of tablets dosage form were assessed in accordance with regulatory guidelines. The results indicate that the drug substance is susceptible to alkaline and oxidative stress. The oxidation degradation led to the identification of three significant unknown degradation impurities. The three compounds were isolated through the application of preparative liquid chromatography, and their structures were determined using analytical techniques such as liquid chromatography-mass spectrometry, high-resolution mass spectrometry and nuclear magnetic resonance spectroscopy. Utilizing structural elucidation data, predictions were made regarding the composition of impurities, revealing them to be novel degradation impurities that bear structural resemblance to ibrutinib. Additionally, potential pathways for the formation of the impurities were proposed.

Favipiravir, remdesivir, and lopinavir: metabolites, degradation products and their analytical methods

Severe acute respiratory syndrome 2 (SARS-CoV-2) caused the emergence of the COVID-19 pandemic all over the world. Several studies have suggested that antiviral drugs such as favipiravir (FAV), remdesivir (RDV), and lopinavir (LPV) may potentially prevent the spread of the virus in the host cells and person-to-person transmission. Simultaneously with the widespread use of these drugs, their stability and action mechanism studies have also attracted the attention of many researchers. This review focuses on the action mechanism, metabolites and degradation products of these antiviral drugs (FAV, RDV and LPV) and demonstrates various methods for their quantification and discrimination in the different biological samples. Herein, the instrumental methods for analysis of the main form of drugs or their metabolite and degradation products are classified into two types: optical and chromatography methods which the last one in combination with various detectors provides a powerful method for routine and stability analyses. Some representative studies are reported in this review and the details of them are carefully explained. It is hoped that this review will be a good guideline study and provide a better understanding of these drugs from the aspects investigated in this study.

Separation and simultaneous estimation of enantiomers and Diastereomers of muscarinic receptor antagonist Solifenacin using stability-indicating Normal-phase HPLC technique with chiral stationary phase amylose tris-(3,5-dimethylphenylcarbamate)

The R,S-enantiomer impurity and diastereomer impurities (S,S-isomer and R,R-isomer) of the solifenacin (S,R-enantiomer) were effectively separated and quantified simultaneously utilizing normal-phase high-performance liquid chromatography with a chiral stationary phase consisting of amylose tris (3,5-dimethylphenylcarbamate) coated on silica-gel (Chiralpak, AD-H). The enantiomeric and stereo-selective separation was achieved within a run time of 35 minutes using a mobile phase of 'n-hexane, ethanol, and diethylamine' in an isocratic elution mode with a detection wavelength of 220 nm. The validation attributes assessed were accuracy (which showed excellent recoveries between 97.5% and 100.4%) and linearity (which was proven in the range of 0.081-1.275 μg.mL-1 , with a linear regression of 0.999). The stress testing experiments proved that the developed methodology by the HPLC technique has stability-indicating characteristics, as all closely eluting peak pairs were separated well with a resolution of 2.3 and without any interference. The proposed methodology was highly efficient in separating and simultaneously determining the chiral impurities (enantiomers and diastereomers) of the solifenacin in the release and stability sample analyses of drug substances and tablets in pharmaceutical formulations.

Development and Validation of Reverse-Phase High-Performance Liquid Chromatography Method for Simultaneous Estimation of Doxorubicin and Clotrimazole

A reverse-phase high-performance liquid chromatographic (RP-HPLC) method was developed to analyze the simultaneous estimation of doxorubicin and clotrimazole. The method was achieved by Nucleodur C18 column with dimension 250 × 4.6 mm (5 μm) using gradient elution. The mobile phase contained 0.2% formic acid (pH 3.2) and acetonitrile. The flow rate was kept at 1.0 mL/min and detection and quantitation of both drugs (doxorubicin and clotrimazole) were achieved using a photodiode array detector at 276 nm, which was the isosbestic point for both drugs. The proposed method was validated according to the current International Council for Harmonization of Technical Requirements of Pharmaceuticals for Human Use guidelines for specificity, linearity, accuracy, precision, and robustness. The developed method showed a linear response (R2 > 0.999), and was accurate (recoveries 97%-103%), precise (resolution ≤1.0%), sensitive, and specific. Thus, the developed RP-HPLC method for the simultaneous estimation of both drugs was successfully validated and can be utilized for the estimation of these drugs in the formulations being developed.

Stability-indicating UPLC assay coupled with mass spectrometry for the analysis of vilanterol degradation products in human urine

Vilanterol is a once-daily dose inhaler prescribed for asthma and chronic obstructive pulmonary disease. This study involved an investigation of vilanterol stability under acidic, basic, oxidative, thermal, and photolytic stress conditions. UPLC method was developed and validated for the analysis of vilanterol with its degradants. The drug was stable under photolytic and thermal stress conditions and degraded under acidic, basic, and oxidative stress conditions. Degradation kinetics was performed for acidic, basic and oxidative stress conditions. Kinetics parameters, K, half-life time (t1/2) and shelf-life time (t90) were assessed, and the degradation followed first order reaction. The method was linear from 0.10 to 100.00 µg mL-1 with accuracy, inter-day and intra-day precision from 99.45 to 100.02%, 0.391-0.694 and 0.041-0.345, respectively. Mass spectrometry was employed to elucidate the structure of the degradants, and the results revealed that certain degradation products were comparable to vilanterol metabolites. The World Anti-Doping Agency has prohibited the presence of vilanterol and its metabolites in athletes' urine except for exercise bronchoconstriction with limited dose. So, quantification of vilanterol in the presence of its degradants was performed in human urine. The results revealed that the method was linear in range of 1.00 to 100.00 µg mL-1. Samples collection and experimental protocol was performed according to the guidelines of the Research Ethics Committee of the Faculty of Pharmacy, the British University in Egypt with approval No. CH-2305.

Automated online deconjugation of antibody-drug conjugate for small molecule drug profiling

Antibody-drug conjugates (ADCs) are designed by chemically linking highly potent cytotoxic small molecule drugs to monoclonal antibodies of unique specificity for targeted destruction of cancer cells. This innovative class of molecules incurs unique developmental challenges due to its structural complexity of having both small molecule and protein components. The stability of the small molecule payload on the ADC is a critical attribute as it directly relates to product efficacy and patient safety. This study describes the use of an end-to-end automated workflow for effective and robust characterization of the small molecule drug while it is conjugated to the antibody. In this approach, online deconjugation was accomplished by an autosampler user defined program and 1D size exclusion chromatography was utilized to provide separation between small molecule and protein species. The small molecule portion was then trapped and sent to the 2D for separation and quantification by reversed-phase liquid chromatography with identification of impurities and degradants by mass spectrometry. The feasibility of this system was demonstrated on an ADC with a disulfide-based linker. This fully automated approach avoids tedious sample preparation that may lead to sample loss and large assay variability. Under optimized conditions, the method was shown to have excellent specificity, sensitivity (LOD of 0.036 µg/mL and LOQ of 0.144 µg/mL), linearity (0.04-72.1 µg/mL), precision (system precision %RSD of 1.7 and method precision %RSD of 3.4), accuracy (97.4 % recovery), stability-indicating nature, and was successfully exploited to analyze the small molecule drug on a panel of stressed ADC samples. Overall, the workflow established here offers a powerful analytical tool for profiling the in-situ properties of small molecule drugs conjugated to antibodies and the obtained information could be of great significance for guiding process/formulation development and understanding pharmacokinetic/pharmacodynamic behavior of ADCs.

A strategic approach towards mass balance investigations in pharmaceutical drug substance release testing: A peculiar out of specification case study encountered during API manufacture

Mass balance in drug substances release testing is a critical quality attribute in pharmaceutical manufacturing that continues to challenge modern analytical characterization. This specific perspective of mass balance is lacking in literature, and the following work addresses the knowledge gap related to this topic by examining an in-depth case study and detailing the systematic investigation into mass imbalance observed during release testing of a small molecule API. The process followed a logical stepwise progression beginning with most probable causes and expanded to more obscure causes that require a deeper examination of the API in question until the undetected impurity in question was finally identified. The discovered impurity was eventually found to be formed from a unique side reaction that led to the formation of API-related oligomer impurities, which had eluded conventional small molecule release testing strategies. Ultimately, the characterization gap was traced back to deficiency in the LC results of the developed API purity methods. More importantly, this gap provides an ideal opportunity to highlight common oversights and pitfalls encountered in early phase pharmaceutical development especially as it relates to the method development of truly representative chromatography methods in the API characterization. The work reflects on the key lessons learned from the highlighted pitfalls that were encountered in this case study and offers strategic insights to guide and to improve the development workflow for drug substance characterization strategies.

Robust fragment-based method of calculating hydrogen atom transfer activation barrier in complex molecules

Dynamic processes driven by non-covalent interactions (NCI), such as conformational exchange, molecular binding, and solvation, can strongly influence the rate constants of reactions with low activation barriers, especially at low temperatures. Examples of this may include hydrogen-atom-transfer (HAT) reactions involved in the oxidative stress of an active pharmaceutical ingredient (API). Here, we develop an automated workflow to generate HAT transition-state (TS) geometries for complex and flexible APIs and then systematically evaluate the influences of NCI on the free activation energies, based on the multi-conformational transition-state theory (MC-TST) within the framework of a multi-step reaction path. The two APIs studied: fesoterodine and imipramine, display considerable conformational complexity and have multiple ways of forming hydrogen bonds with the abstracting radical-a hydroxymethyl peroxyl radical. Our results underscore the significance of considering conformational exchange and multiple activation pathways in activation calculations. We also show that structural elements and NCIs outside the reaction site minimally influence TS core geometry and covalent activation barrier, although they more strongly affect reactant binding and consequently the overall activation barrier. We further propose a robust and economical fragment-based method to obtain overall activation barriers, by combining the covalent activation barrier calculated for a small molecular fragment with the binding free energy calculated for the whole molecule.

A Rapid 3-Day Excipient Screening Methodology and its Application in Identifying Chemical Stabilizers for Solid Formulations with Mixed Mechanisms of Degradation

This study outlines a practical approach for assessing chemical instability by heating the drug-excipient binary mixtures or multi-excipient formulations at 75°C for 3 days before characterization. Differentiating itself from other excipient compatibility methods, our methodology necessitates a saturated aqueous slurry rather than arbitrarily fixed water content. This allows bulk and surface water in the excipient to contribute to drug degradation. The synergistic impact of surface water and elevated temperature expedites degradation kinetics, resulting in accelerated data generation. Among excipient compatibility methods available, our method is quantitative and merges with traditionally used methodologies. The devised nomograph enables extrapolation of shelf life at 20°C from experimental data obtained at 75°C. This methodology also helped identify stabilizers for the drug NVS-1 where traditional excipient compatibility programs had failed. Incorporation of monovalent salts, such as sodium/potassium chloride and sodium bicarbonate at 5% w/w, significantly enhanced the chemical stability of NVS-1, ensuring stable tablet formulations. Our hypothesis posits that stabilization is due to increased ionic strength in the slurry, which stabilizes an induced dipole within the polar NVS-1 drug. Additionally, the presence of ions in the moisture layer is anticipated to stabilize π-π stacking of two planar aromatic NVS-1 molecules. The expedited generation of experimental data allowed the identification of inorganic salts to supplement a standard excipient compatibility screening panel. Considering the economic implications of stability testing methodologies in effort, cost, and duration, a faster turnaround in chemical stability data enhances formulation selection. This ultimately facilitates the development of drug formulations with greater efficiency without delays.

Insight into the degradation of amino substituted benzimidazo[1,2-a]quinolines via a combined experimental and density functional theory study

Heterocyclic compounds have been shown to be potential chemotherapeutic agents, especially the benzimidazole derivatives studied in this work. The ultimate goal in the search for biologically active and effective molecules is to commercialize a product whose stability must be reliable. Therefore, in the development of drugs, forced degradation experiments are performed under the environmental conditions to which they are subjected during transportation and storage to ensure quality and safety before marketing. Hydrolytic, thermal, photolytic, and degradation in the presence of hydrogen peroxide are experimental stress tests to which the newly synthesized compounds were subjected to gain insight into the degradation pathways of the analytes. Degradation of two benzimidazole derivatives was observed under all applied conditions while the major impact showed photolysis with ten and four degradation products, respectively. In total, eighteen major degradation products were detected and identified using high-resolution mass spectrometry. Computer models in the TEST program were applied to the proposed structures to evaluate the bioaccumulation factor, toxicity, and mutagenicity of the analyzed compounds, while density functional theory analysis (DFT) revealed factors affecting the vulnerability of systems towards exceeding acidic/basic conditions and H2O2.

Differential role of potential stressors, underlying degradation mechanism, characterization of degradants using LC-MS/MS, and establishment of a stability-indicating analytical method for duvelisib

Duvelisib (DUV) was first approved globally in 2018. An extensive literature search revealed that the differential role of a potential degradation medium in altering the shelf-life of DUV due to its exposure during storage has not been identified till date. Moreover, its degradation impurities and degradation mechanism are not known. In addition, no analytical method has been reported for the quantification of DUV in the presence of its degradation impurities. Therefore, the aim of this study was to identify the impact of different potential degradation media on the stability of DUV, establish the degradation mechanism, and identify its major degradation impurities. The aim was also to establish a stability-indicating analytical method for the quantification of DUV in the presence of its degradation impurities. This study is the first to report the structure of degradation impurities and the step-by-step degradation mechanism of DUV. This information will be useful for the scientific community and manufacturers in optimizing the formulation parameters and/or storage conditions. The validated method can be employed for analysis of stability study and routine quality control samples of newer DUV formulations in pharmaceutical industries. The identified impurities may serve as impurity standards for specifying their limits in the drug after required qualification studies.

Expeditive Chromatographic Methods for Quantification of Solifenacin Succinate along with its Official Impurity as the Possible Acid Degradation Product

Two selective stability-indicating procedures were adopted for the quantification of Solifenacin succinate (SOL) along with its acid degradant, in its powder form or in pharmaceutical tablet. Under stress conditions, the acid degradation pathway of SOL was investigated, its official impurity (SOL imp-A) was obtained as the possible acid degradation product, also. A densitometric technique based on the separation of SOL from SOL imp-A employing HPTLC plates prelaminated with silica gel 60 F254 as the stationary phase and a developing solution containing methanol:chloroform:ammonia (8:1:1, v/v/v) and UV scanning of the developed bands at 220 nm. Linear regression analysis data for the calibration plot of SOL showed perfect linear relationships throughout the range of concentration 10-60 μg/band. A reversed phase C18 analytical column (4.6 × 250 mm, 5 μm) was also used to separate the mixture at a flow rate of 1 mL/min, using acetonitrile:0.05 M phosphate buffer (70:30, v/v) as the mobile phase and phosphoric acid to set pH = 3.5. Quantification was obtained at 220 nm using peak area and linear calibration curve across a concentration range of 10-70 μg/mL. The recommended procedures were applied to the existing dosage form, and they generated satisfactory results.

Application of Accelerated Predictive Stability Studies in Extemporaneously Compounded Formulations of Chlorhexidine to Assess the Shelf Life

Industrially fabricated medicines have a well-defined shelf life supported by rigorous studies before their approval for commercialization. However, the shelf life of extemporaneous compounding topical formulations prepared at hospitals tends to be shorter, especially when no data are available to prove a longer stability period. Also, the storage conditions are unknown in many circumstances. Accelerated Predictive Stability (APS) studies have been shown to be a useful tool to predict in a faster and more accurate manner the chemical stability of extemporaneously compounded formulations requiring a minimum amount of formulation, thereby reducing the chemical drug waste per study. Shelf life will be allocated based on scientific data without compromising drug efficacy or safety. In this work, the APS approach was applied to the commercially available Cristalmina® (CR) and an extemporaneously compounded formulation of chlorhexidine (DCHX). A different degradation kinetic was found between DCHX and CR (Avrami vs. zero-order kinetics, respectively). This can explain the different shelf life described by the International Council for Harmonisation of Technical Requirements Registration Pharmaceuticals Human Use (ICH) conditions between both formulations. A predicted stability for the DCHX solution was obtained from the extrapolation of the degradation rate in long-term conditions from the Arrhenius equation. The estimated degradation from the Arrhenius equation for DCHX at 5 °C, 25 °C, and 30 °C at 365 days was 3.1%, 17.4%, and 25.9%, respectively. The predicted shelf life, in which the DCHX content was above 90%, was 26.67 months under refrigerated conditions and 5.75 and 2.24 months at 25 and 30 °C, respectively. Currently, the Spanish National Formulary recommends a shelf life of no longer than 3 months at room temperature for DCHX solution. Based on the predicted APS and confirmed by experimental long-term studies, we have demonstrated that the shelf life of DCHX extemporaneously compounded formulations could be prolonged by up to 6 months.

LC-MS Approach to Decipher a Light Chain Chromatographic Peak Splitting of a Monoclonal Antibody

PURPOSE

Monoclonal antibodies (mAbs), like other protein therapeutics, are prone to various forms of degradation, some of which are difficult to distinguish from the native form yet may alter potency. A generalizable LC-MS approach was developed to enable quantitative analysis of isoAsp. In-depth understanding of product quality attributes (PQAs) enables optimization of the manufacturing process, better formulation selection, and decreases risk associated with product handling in the clinic or during shipment.

METHODS

Reversed-phase chromatographic peak splitting was observed when a mAb was exposed to elevated temperatures. Multiple LC-MS based methods were applied to identify the reason for peak splitting. The approach involved the use of complementary HPLC columns, multiple enzymatic digestions and different MS/MS ion dissociation methods. In addition, mAb potency was measured by enzyme-linked immunosorbent assay (ELISA).

RESULTS

The split peaks had identical masses, and the root cause of the peak splitting was identified as isomerization of an aspartic acid located in the complementarity-determining region (CDR) of the light chain. And the early eluting and late eluting peaks were collected and performed enzymatic digestion to confirm the isoAsp enrichment in the early eluting peak. In addition, decreased potency was observed in the same heat-stressed sample, and the increased isoAsp levels in the CDR correlate well with a decrease of potency.

CONCLUSION

Liquid chromatography-mass spectrometry (LC-MS) has been utilized extensively to assess PQAs of biological therapeutics. In this study, a generalizable LC-MS-based approach was developed to enable identification and quantitation of the isoAsp-containing peptides.

Long-term physicochemical stability of 5-fluorouracil at selected standardised rounded doses in polyolefin bags

BACKGROUND

Chemotherapy doses are usually prescribed on the basis of body surface area but dose banding is emerging as an efficient alternative. Dose banding presents the possibility of in-advance preparation in a Centralized Intravenous Admixture Service.

AIM OF THE STUDY

To evaluate the long-term stability of 5-fluorouracil at banded doses (700 mg and 800 mg) in polyolefin bags.

MATERIALS AND METHODS

Ten polyolefin bags were prepared under aseptic conditions and stored at 23 ± 2°C for 24 days. Five of them were composed of 14 mL 5-fluorocuracil (700 g) in 100 mL 0.9% sodium chloride solution and the five other of 16 mL 5-fluorouracil (800 mg) in 100 mL 0.9% sodium chloride solution. At defined times, physical stability parameters were assessed: optical densities, pH measurements, visual and microscopical inspections. Solutions concentrations were measured using high-performance liquid chromatography coupled with a photodiode array detector.

RESULTS

No change was observed on pH and optical density measurements during the study period. Visual and microscopical inspections remained free of colour change, precipitate, microagregate or crystal. The concentrations of 5-Fluorouracil in 800 mg bags remained stable for 24 days while the concentration in 700 mg bags showed a stability of at least 17 days.

CONCLUSION

Five-fluorouracil at banded doses of 700 and 800 mg in polyolefin bags is physicochemically stable for at least 17 days at 23 ± 2°C. These results support the possibility of in advance centralised preparation.

Separation and quantitative estimation of stereo-selective enantiomers of montelukast in pharmaceutical drug substance and tablets dosage forms by using stability-indicating normal phase-HPLC method

Montelukast sodium (MLS) is a leukotriene receptor antagonist that relieves asthma, bronchospasm, allergic rhinitis, and urticaria. A simple, robust, and stability-indicating normal phase high-performance liquid chromatography method was developed to separate and quantitatively estimate the S-enantiomer of MLS. The chiral separation was achieved using USP L51 packing material along with a mobile phase consisting of a solvent mixture (n-hexane, ethanol, and propionic acid), a flow rate of 1.0 mL/min, a detection wavelength of 284 nm, a column temperature of 30°C and an injection volume of 20 μL. The enantiomers peaks were well separated from the peaks of the placebo, diluting solvent, MLS, and its known impurities with a resolution of more than 2.2 and with no interference. Accuracy and linearity were studied in a range of 0.36-3.597 μg/mL (0.03%-0.30%), with good recoveries between 92.5% and 96.8% and a linear regression coefficient above 0.996. The suggested chiral chromatography method is being considered as an alternative and equivalent method to the United States Pharmacopeia and European Pharmacopeia monographs. The developed method was effectively employed for the study of release and stability samples of MLS. This HPLC method is also capable of separating and estimating the stereo-selective isomers (R- and S-enantiomers) of sulfoxide impurity of MLS in pharmaceutical medicine.

A quality by design approach for the synthesis of palmitoyl-L-carnitine-loaded nanoemulsions as drug delivery systems

Nanoemulsions (NE) are lipid nanocarriers that can efficiently load hydrophobic active compounds, like palmitoyl-L-carnitine (pC), used here as model molecule. The use of design of experiments (DoE) approach is a useful tool to develop NEs with optimized properties, requiring less experiments compared to trial-and-error approach. In this work, NE were prepared by the solvent injection technique and DoE using a two-level fractional factorial design (FFD) as model was implemented for designing pC-loaded NE. NEs were fully characterized by a combination of techniques, studying its stability, scalability, pC entrapment and loading capacity and biodistribution, which was studied ex-vivo after injection of fluorescent NEs in mice. We selected the optimal composition for NE, named pC-NE_U, after analysis of four variables using DoE. pC-NE_U incorporated pC in a very efficient manner, with high entrapment efficiency (EE) and loading capacity. pC-NE_U did not change its initial colloidal properties stored at 4 °C in water during 120 days, nor in buffers with different pH values (5.3 and 7.4) during 30 days. Moreover, the scalability process did not affect NE properties and stability profile. Finally, biodistribution study showed that pC-NE_U formulation was predominantly concentrated in the liver, with minimal accumulation in spleen, stomach, and kidneys.

Pharmaceutical Forced Degradation (Stress Testing) Endpoints: A Scientific Rationale and Industry Perspective

Forced degradation (i.e., stress testing) of small molecule drug substances and products is a critical part of the drug development process, providing insight into the intrinsic stability of a drug that is foundational to the development and validation of stability-indicating analytical methods. There is a lack of clarity in the scientific literature and regulatory guidance as to what constitutes an "appropriate" endpoint to a set of stress experiments. That is, there is no clear agreement regarding how to determine if a sample has been sufficiently stressed. Notably, it is unclear what represents a suitable justification for declaring a drug substance (DS) or drug product (DP) "stable" to a specific forced degradation condition. To address these concerns and to ensure all pharmaceutically-relevant, potential degradation pathways have been suitably evaluated, we introduce a two-endpoint classification designation supported by experimental data. These two endpoints are 1) a % total degradation target outcome (e.g., for "reactive" drugs) or, 2) a specified amount of stress, even in the absence of any degradation (e.g., for "stable" drugs). These recommended endpoints are based on a review of the scientific literature, regulatory guidance, and a forced degradation data set from ten global pharmaceutical companies. The experimental data set, derived from the Campbell et al. (2022) benchmarking study,1 provides justification for the recommendations. Herein we provide a single source reference for small molecule DS and DP forced degradation stress conditions and endpoint best practices to support regulatory submissions (e.g., marketing applications). Application of these forced degradation conditions and endpoints, as part of a well-designed, comprehensive and a sufficiently rigorous study plan that includes both the DS and DP, provides comprehensive coverage of pharmaceutically-relevant degradation and avoids unreasonably extreme stress conditions and drastic endpoint recommendations sometimes found in the literature.

Selective Stability Indicating Liquid Chromatographic Method Based on Quality by Design Framework and In Silico Toxicity Assessment for Infigratinib and Its Degradation Products

Infigratinib, a protein kinase inhibitor employed in the therapeutic management of cholangiocarcinoma, was subjected to various stress conditions, including hydrolytic (acidic and alkaline), oxidative, photolytic, and thermal stress, in accordance with the rules established by the International Council for Harmonization. A cumulative count of five degradation products was observed. The application of the Quality by Design principle was utilized in the development of a rapid and specific separation method for Infigratinib and its degradation products. The methodology employed in this study was derived from an experimental design approach, which was utilized to examine the critical process parameters associated with chromatographic systems. The reversed-phase high-performance liquid chromatography technique, employing a C18 column and a mobile phase composed of a gradient mixture of 25 mM ammonium acetate buffer at pH 6.0 and acetonitrile, successfully facilitated the chromatographic separation. The methodology was expanded to include the utilization of UPLC-quadrupole tandem mass spectrometry in order to conduct a comprehensive analysis of the structural properties and characterize the degradation products. Overall, five degradation products were found in different stress conditions. The method was verified at certain working points, wherein a linearity range (5.0-200.0 µg/mL) was developed and other parameters such as accuracy, repeatability, selectivity, and system suitability were evaluated. Finally, the toxicity and mutagenicity of Infigratinib and its degradation products were predicted using in silico software, namely DEREK Nexus® (version 6.2.1) and SARAH Nexus® (version 3.2.1). Various toxicity endpoints, including chromosomal damage, were predicted. Additionally, two degradation products were also predicted to be mutagenic.

Development and Validation of LC-MS/MS Method for the Determination of 1-Methyl-4-Nitrosopiperazine (MNP) in Multicomponent Products with Rifampicin-Analytical Challenges and Degradation Studies

Rifampicin is an essential medicine for treating and preventing tuberculosis (TB). TB is a life-threatening infectious disease and its prevention and treatment are public health imperatives. In the time of a global crisis of nitrosamine contamination of medicinal products, patient safety and a reduction in the number of drug recalls at the same time are crucial. In this work, the LC-MS/MS method was developed for the determination of the 1-methyl-4-nitrosospiperazine (MNP), a genotoxic nitrosamine impurity in various products containing rifampicin at a 5.0 ppm limit level according to Food and Drug Administration (FDA). Extraction with neutralization was necessary due to the matrix and solvent effect associated with the complexity of the rifampicin product. The developed method was validated in accordance with regulatory guidelines. Specificity, accuracy, precision, limit of detection, and limit of quantification parameters were evaluated. The recovery of the MNP was 100.38 ± 3.24% and the intermediate precision was 2.52%. The contamination of MNP in Rifampicin originates in the manufacturing process of the drug. Furthermore, the results of the forced degradation experiments show that the formation of MNP is possible by two mechanisms: through degradation of rifampicin and the oxidation of 1-amino-4-methyl-piperazine. This article points out that it is necessary to monitor and describe degradation products and the mechanism of degradation of potentially affected active pharmaceutical ingredient (API) with respect to the formation of nitrosamines during stress testing, as it was done in the following work for rifampicin in multicomponent products.

Stability-Indicating Densitometric Analysis of Evogliptin Tartrate in Bulk and Tablet Dosage Form

BACKGROUND

Evogliptin tartrate is a novel dipeptidyl peptidase (DPP-4) inhibitor very recently introduced into the market as an oral hypoglycemic drug.

OBJECTIVE

The literature review has revealed no reports of stability-indicating analytical methods so far for evogliptin tartrate. Thus, the goal of this study was to develop and validate a stability-indicating high-performance thin-layer chromatography (HPTLC) method for evogliptin tartrate in bulk and tablet dosage form.

METHOD

For the study, precoated plates of silica gel 60F254 were used as stationary phase and acetonitrile-water-formic acid (30:8:2, v/v/v) was used as a developing system. The densitometric scanning was performed at 270 nm, and the method was validated as per International Council for Harmonisation (ICH) guidelines for accuracy, precision, limit of detection (LOD), and limit of quantitation (LOQ). Evogliptin was subjected to forced degradation studies and was exposed to various stress conditions such as acid/base hydrolysis, oxidation, thermal stress, and UV light.

RESULTS

The developed method furnished compact spots of evogliptin (Rf 0.62 ± 0.05) and was linear in the concentration range of 1-5 µg/spot. The lowest detection and quantitation values were found to be 0.331 and 1.003 µg/spot, respectively, and % recovery was found to be 101.09. The low RSD values (below 2%) for intra-day (% RSD 1.86) and inter-day (% RSD 1.43) precision studies demonstrated the preciseness of the developed method.

CONCLUSIONS

All the validation parameters were found to be within the acceptable range prescribed by ICH guidelines, indicating that the developed method was accurate, precise, selective, and reproducible. A total of five degradation products were resolved under various stress conditions.

HIGHLIGHTS

The proposed method has a promising application commercially for identification, routine quantitative determination, and monitoring of stability of the evogliptin tartrate in bulk and tablet dosage forms to guarantee its safety, efficacy, and quality. Moreover, the developed method will also help in formulation development and in determining the appropriate storage conditions.

Validation of stability-indicating LC method, degradation study, and impact on antioxidant and antifungal activities of Eugenia uniflora leaves extract

The aim of this study is to demonstrate the stability-indicating capacity of an analytical method for Eugenia uniflora, enhance understanding of the stability of myricitrin, and assess the effect of degradation of spray-dried extract (SDE) on antioxidant and antifungal activities. Validation of the stability-indicating method was carried out through a forced degradation study of SDE and standard myricitrin. The antioxidant and antifungal activities of SDE were evaluated both before and after degradation. The quantification method described was found to be both accurate and precise in measuring myricitrin levels in SDE from E. uniflora, with excellent selectivity that confirmed its stability-indicating capability. The forced degradation study revealed that the marker myricitrin is sensitive to hydrolysis, but generally stable under other stress conditions. By contrast, the standard myricitrin displayed greater susceptibility to degradation under forced degradation conditions. Analysis of the antioxidant activity of SDE before and after degradation showed a negative impact in this activity due to degradation, while no significant effect was observed on antifungal activity. The method described can be a valuable tool in the quality control of E. uniflora, and the findings can assist in determining the optimal conditions and storage of products derived from this species.

Identification and structural characterization of major stress degradation products of halcinonide by liquid chromatography-high-resolution mass spectrometry

Halcinonide is a topical corticosteroid approved by the US Food and Drug Administration (FDA), known for its anti-inflammatory and antipruritic properties. The therapeutic benefits of halcinonide have rendered it an effective treatment regimen for various dermatological conditions such as psoriasis, dermatitis, and eczema. However, stability of the drug substance is a prerequisite in determining the therapeutic efficacy and plays a crucial role during formulation development and long-term storage. As corticosteroids are highly susceptible to degradation, the current study aims to expose halcinonide to different stress conditions and understand its stability behavior. An HPLC method was developed for the separation of halcinonide and its degradation products. Separation was accomplished in gradient mode using an Eclipse Plus C18 column (250 × 4.5 mm, 5 μm) with ammonium formate (10 mM, pH 6.5) and acetonitrile as the mobile phases. LC-Q-TOF/MS/MS studies were conducted on halcinonide, which led to the identification of degraded products using optimized mass parameters. A potential mechanistic degradation pathway for halcinonide, along with the major identified degradation products has been established. The chromatographic method that was developed has been validated in compliance with the Q2(R1) guideline of the International Council for Harmonization. ProTox-II was used to perform in silico toxicity studies in order to evaluate the toxicity potential of both halcinonide and the identified degradation products.

Portable capillary LC for in-line UV monitoring and MS detection: Comparable sensitivity and much lower solvent consumption

Pharmaceutical development currently relies on quality separation methods from early discovery through to line-of-site manufacturing. There have been significant advancements made regarding the column particle packing, internal diameter, length connectivity, the understanding of the impact key parameters like void volume, flow rate, and temperature all that affects the resultant separation quality, that is, resolution, peak shape, peak width, run time, and signal-to-noise ratio. There is however a strong need to establish better alternatives to large bulky high-performance liquid chromatography racks either for process analytical reaction monitoring or mass spectrometry analysis in establishing product quality. Compact, portable high-pressure liquid chromatography can be a more efficient alternative to traditional ultra-high pressure liquid chromatography and traditional liquid chromatography. The compact versatile instrument evaluated here allows good separation control with either the on-board column with fixed ultra-violet wavelength cartridge or for use with a high-resolution mass spectrometry. Significant space reduction results in greener lab spaces with improved energy efficiency for smaller labs with lower energy demands. In addition, this compact liquid chromatography was used as a portable reaction monitoring solution to compare forced degradation kinetics and assess portable liquid chromatography-mass spectrometry capability for the analyses required for pharmaceutical drug product testing.

Exquisite integration of quality-by-design and green analytical approaches for simultaneous determination of xylometazoline and antazoline in eye drops and rabbit aqueous humor, application to stability study

This work implements a stability indicating HPLC method developed to simultaneously determine xylometazoline (XYLO) and antazoline (ANT) in their binary mixture, rabbit aqueous humor and cited drug's degradates by applying analytical quality-by-design (AQbD) combined with green analytical chemistry (GAC) experiment for the first time. This integration was designed to maximize efficiency and minimize environmental impacts, as well as energy and solvent consumption. Analytical quality-by-design was applied to achieve our aim starting with evaluation of quality risk and scouting analysis, tracked via five parameters chromatographic screening using Placket-Burman design namely: pH, temperature, organic solvent percentage, flow rate, and wavelength detection. Recognizing the critical method parameters was done followed by optimization employing central composite design and Derringer's desirability toward assess optimum conditions that attained best resolution with satisfactory peak symmetry with short run time. Optimal chromatographic separation was attained by means of an XBridge® C18 (4.6 × 250 mm, 5 µm) column through isocratic elution using a mobile phase consists of phosphate buffer (pH 3.0): ethanol (60:40, by volume) at a 1.6 mL/min flow rate and 230.0 nm UV detection. Linearity acquired over a concentration range of 1.0-100.0 µg/mL and 0.5-100.0 µg/mL for XYLO and ANT, respectively. Furthermore, imperiling cited drugs' stock solutions to stress various conditions and satisfactory peaks of degradation products were obtained indicating that cited drugs are vulnerable to oxidative degradation and basic hydrolysis. Degradates' structures were elucidated using mass spectrometry. Applying various assessment tools; namely: analytical greenness (AGREE), green analytical procedure index (GAPI), analytical eco-scale, and national environmental method index (NEMI), Greenness method's evaluation was applied and proved to be green. In fact, the developed method is established to be perceptive, accurate, and selective to assess cited drugs for routine analysis.

Identification, Synthesis, and Characterization of Potential Oxidative Impurities of Venetoclax: Application of Meisenheimer Rearrangement

Venetoclax is a potent BCL-2 inhibitor that is used for the treatment of several blood cancers. During the oxidative stress degradation of venetoclax, we observed the formation of two potential impurities at levels of about 8-10%, which have similar molecular weights. The two impurities were isolated and identified as 4-(3-((1H-pyrrolo[2,3-b]pyridin-5-yl)oxy)-4-(((3-nitro-4-(((tetrahydro-2H-pyran-4-yl)methyl)amino)phenyl)sulfonyl)carbamoyl)phenyl)-1-((4'-chloro-5,5-dimethyl-3,4,5,6-tetrahydro-[1,1'-biphenyl]-2-yl)methyl)piperazine 1-oxide (venetoclax N-oxide, VNO) and 2-((1H-pyrrolo[2,3-b]pyridin-5-yl)oxy)-4-(4-((4'-chloro-5,5-dimethyl-3,4,5,6-tetrahydro-[1,1'-biphenyl]-2-yl)methoxy)piperazin-1-yl)-N-((3-nitro-4-(((tetrahydro-2H-pyran-4-yl)methyl)amino)phenyl)sulfonyl)benzamide (venetoclax hydroxylamine impurity, VHA). To confirm these two compounds, we have synthesized each impurity individually and analyzed it by high-performance liquid chromatography, mass spectrometry, 1H NMR, 13C NMR, and 2D NMR. VNO was synthesized by the oxidation of venetoclax using m-CPBA in dichloromethane to get the required N-oxide impurity. After the confirmation of the VNO impurity, the VNO impurity was heated with water at reflux in a sealed tube for 36 h to get the VHA impurity of about 6-8% after 36 h. After thorough analysis, it was confirmed that venetoclax N-oxide undergoes [1,2] Meisenheimer rearrangement to form the venetoclax hydroxylamine impurity. These two impurities may be relevant reference standards in manufacturing venetoclax Active Pharmaceutical Ingredient (API) (or) tablets.

Effect of atmosphere and relative humidity on photodegradation of clopidogrel under artificial solar and indoor light irradiation

Knowledge of the chemical stability of active pharmaceutical ingredients (APIs) is an important issue in the drug development process. This work describes a methodical approach and a comprehensive protocol for forced photodegradation studies of solid clopidogrel hydrogen sulfate (Clp) under artificial sunlight and indoor irradiation at different relative humidities (RHs) and atmospheres. The results showed that, at low RHs (up to 21%), this API was relatively resistant to simulated sunlight as well as indoor light. However, at higher RHs (between 52% and 100%), more degradation products were formed, and the degradation rate increased with rising RH. The influence of oxygen on the degradation was relatively low, and most degradation reactions proceeded even in humid argon atmosphere. The photodegradation products (DP) were analyzed with two different HPLC systems (LC-UV, LC-UV-MS) and selected impurities were separated by a semi-preparative HPLC and identified by high resolution mass spectrometry (ESI-TOF-MS) and 1H NMR techniques. Based on the obtained results, a light induced degradation pathway could be proposed for Clp in solid state.

Stability-indicating normal-phase HPLC method development for separation and quantitative estimation of S-enantiomer of lacosamide in pharmaceutical drug substance and tablet dosage form

Lacosamide (LA) is an antiepileptic medicine that is used to treat tonic-clonic seizures, partial-onset seizures, mental problems, and pain. A simple, effective, and reliable normal-phase liquid chromatographic technique was developed and validated to separate and estimate the enantiomer of (S-enantiomer) LA in pharmaceutical drug substance and drug product. Normal-phase LC was performed using USP L40 packing material (250 × 4.6 mm, 5 μm) and a mobile phase of n-hexane and ethanol at 1.0 ml min-1 . The detection wavelength, column temperature, and injection volume used were 210 nm, 25°C, and 20 μl, respectively. The enantiomers (LA and S-enantiomer) were completely separated using a minimum resolution of 5.8 and accurately quantified without any interference in a 25-min run time. Accuracy study for stereoselective and enantiomeric purity trials was conducted between 10 and 200%, with recovery values ranging from 99.4 to 103.1% and linear regression values >0.997. The stability-indicating characteristics were assessed using forced degradation tests. The proposed normal-phase HPLC technique is an alternate approach to the official monograph methods (USP and Ph.Eur.) of LA, and it was successfully used in the evaluation of release and stability samples for both tablet dosage forms and pharmaceutical substances.

Chromatographic reversed HPLC and TLC-densitometry methods for simultaneous determination of serdexmethylphenidate and dexmethylphenidate in presence of their degradation products-with computational assessment

Two Chromatographic methods have been established and optimized for simultaneous determination of serdexmethylphenidate (SER.DMP) and dexmethylphenidate (DMP) in the presence of their degradation products. The first method is a reversed phase high performance liquid chromatography with diode array detection (HPLC-DAD). Isocratic separation was carried out on Waters X-bridge Shield RP₁₈ column (150×3.9×5 μm particle size) using a mixture of 5 mM phosphate buffer (pH 5.5): acetonitrile (40:60, v/v) as a mobile phase, flow rate 1 mL/min and detection at 220 nm. The second method is a thin-layer chromatography (TLC)-densitometry method using methanol: chloroform (70:30, v/v) as a mobile phase and UV scanning at 220 nm. In HPLC method, the linearity range of SER.DMP was (2.5-25 μg/mL); with LOD (0.051 μg/mL) and LOQ (0.165 μg/mL) while for DMP was (2.5-25 μg/mL); with LOD and LOQ of (0.098 μg/mL) and (0.186 μg/mL), respectively. For TLC method the sensitivity range of SER.DMP was (5-25 μg/mL), LOD was (0.184 μg/spot), while LOQ was (0.202 μg/ spot) whereas for DMP the sensitivity range was (5-25 μg/mL) with LOD of (0.115 μg/ spot) and LOQ of (0.237 μg/ spot), respectively. SER.DMP was found to be equally labile to acidic and alkaline hydrolysis, whereas DMP was sensitive to acidic hydrolysis only. Both drugs were successfully determined in presence of acidic and basic degradants by the two developed methods (stability indicating assay method). Chromatographic separation of the degradation products was carried out on TLC aluminum silica plates 60 F254, as a stationary phase, using methanol: dichloroethane: acetonitrile (60:20:20 v/v), as a mobile phase. The degradation pathway was confirmed using TLC, IR, ¹H-NMR and mass spectroscopy; moreover, the separation power was correlated to the computational results by applying molecular dynamic simulation. The developed methods were validated according to the International Conference on Harmonization (ICH) guidelines demonstrating good accuracy and precision. They were successfully applied for quantitation of SER.DMP and DMP in pure and capsule forms. The results were statistically compared with those obtained by the reported method in terms of accuracy, precision and robustness, and no significant difference was found.

Biobased natural deep eutectic system as versatile solvents: Structure, interaction and advanced applications

The increasing emphasis on the development of green replacements to traditional organic solvents and ionic liquids (ILs) can be attributed to the rising concerns over human health and detrimental impacts of conventional solvents towards the environment. A new generation of solvents inspired by nature and extracted from plant bioresources has evolved over the last few years, and are referred to as natural deep eutectic solvents (NADES). NADES are mixtures of natural constituents like sugars, polyalcohols, sugar-based alcohols, amino acids and organic acids. Interest in NADES has exponentially grown over the last eight years, which is evident from an upsurge in the number of research projects undertaken. NADES are highly biocompatible as they can be biosynthesized and metabolized by nearly all living organisms. These solvents pose several noteworthy advantages, such as easy synthesis, tuneable physico-chemical properties, low toxicity, high biodegradability, solute sustainability and stabilization and low melting point. Research on the applicability of NADES in diverse areas is gaining momentum, which includes as - media for chemical and enzymatic reactions; extraction media for essential oils; anti-inflammatory and antimicrobial agent; extraction of bioactive composites; as chromatographic media; preservatives for labile compounds and in drug synthesis. This review gives a complete overview of the properties, biodegradability and toxicity of NADES which we propose can assist in further knowledge generation on their significance in biological systems and usage in green and sustainable chemistry. Information on applications of NADES in biomedical, therapeutic and pharma-biotechnology fields is also highlighted in the current article along with the recent progress and future perspectives in novel applications of NADES.

Mechanochemical Oxidative Degradation of Thienopyridine Containing Drugs: Toward a Simple Tool for the Prediction of Drug Stability

The long-term stability of an active-pharmaceutical ingredient and its drug products plays an important role in the licensing process of new pharmaceuticals and for the application of the drug at the patient. It is, however, difficult to predict degradation profiles at early stages of the development of new drugs, making the entire process very time-consuming and costly. Forced mechanochemical degradation under controlled conditions can be used to realistically model long-term degradation processes naturally occurring in drug products, avoiding the use of solvents, thus excluding irrelevant solution-based degradation pathways. We present the forced mechanochemical oxidative degradation of three platelet inhibitor drug products, where the drug products contain thienopyridine. Model studies using clopidogrel hydrogen sulfate (CLP) and its drug formulation Plavix show that the controlled addition of excipients does not affect the nature of the main degradants. Experiments using drug products Ticlopidin-neuraxpharm and Efient show that significant degradation occurs after short reaction times of only 15 min. These results highlight the potential of mechanochemistry for the study of degradation processes of small molecules relevant to the prediction of degradation profiles during the development of new drugs. Furthermore, these data provide exciting insights into the role of mechanochemistry for chemical synthesis in general.

Rational Design of Topical Semi-Solid Dosage Forms-How Far Are We?

Specific aspects of semi-solid dosage forms for topical application include the nature of the barrier to be overcome, aspects of susceptibility to physical and chemical instability, and a greater influence of sensory perception. Advances in understanding the driving forces of skin penetration as well as the design principles and inner structure of formulations, provide a good basis for the more rational design of such dosage forms, which still often follow more traditional design approaches. This review analyses the opportunities and constraints of rational formulation design approaches in the industrial development of new topical drugs. As the selection of drug candidates with favorable physicochemical properties increases the speed and probability of success, models for drug selection based on theoretical and experimental approaches are discussed. This paper reviews how progress in the scientific understanding of mechanisms and vehicle-influence of skin penetration can be used for rational formulation design. The characterization of semi-solid formulations is discussed with a special focus on modern rheological approaches and analytical methods for investigating and optimizing the chemical stability of active ingredients in consideration of applicable guidelines. In conclusion, the combination of a good understanding of scientific principles combined with early consideration of regulatory requirements for product quality are enablers for the successful development of innovative and robust semi-solid formulations for topical application.

Identification and enrichment of a UV-induced degradant of Anagrelide drug substance

Anagrelide (ANG) is a widely used drug for the treatment of essential thrombocytosis and myeloproliferative neoplasms. Recently, a new oxidative degradant was identified when the drug product capsule underwent stress testing. Full structural characterization of this previously unidentified degradant was conducted. Preliminary LC-MS analysis indicated the targeted degradant as a mono-oxygenated product of ANG. For the purpose of facile isolation and purification, various forced degradation conditions were screened to enrich the desired degradant, among which, pyridinium chlorochromate (PCC)-treatment effectively afforded a yield of 55 % unknown degradant. Following isolation by prep-HPLC, 1D and 2D NMR studies and HRMS characterization assigned the products as a pair of 5-hydroxy-Anagrelide (5-OH-ANG) enantiomers. A plausible mechanism of formation is proposed.

Azobisisobutyronitrile loaded on mesoporous silica particles: A new stressor for solid-state oxidative forced degradation studies

A new approach for testing drug sensitivity to autooxidative degradation in the solid state is demonstrated in this work. A novel solid-state form of stressing agent for autooxidation has been proposed, based on azobisisobutyronitrile loaded into mesoporous silica carrier particles. The new solid-state form of the stressing agent was applied in degradation studies of two active pharmaceutical ingredients: bisoprolol and abiraterone acetate. The effectiveness and predictivity of the method were evaluated by comparing impurity profiles with those obtained by traditional stability testing of commercial tablets containing the investigated APIs. The results obtained by the new solid-state stressor were also compared with those obtained by an existing method for testing peroxide oxidative degradation in the solid state using a complex of polyvinylpyrrolidone with hydrogen peroxide. It was found that the new silica particle-based stressor was able to effectively predict which impurities could be formed by autooxidation in tablets and that this new approach is complementary to methods for testing peroxide oxidative degradation known from the literature.