Degradation Impurities Research Articles

Building machine-learning-based models for retention time and resolution predictions in ion pair chromatography of oligonucleotides

Support vector regression models are created and used to predict the retention times of oligonucleotides separated using gradient ion-pair chromatography with high accuracy. The experimental dataset consisted of fully phosphorothioated oligonucleotides. Two models were trained and validated using two pseudo-orthogonal gradient modes and three gradient slopes. The results show that the spread in retention time differs between the two gradient modes, which indicated varying degree of sequence dependent separation. Peak widths from the experimental dataset were calculated and correlated with the guanine-cytosine content and retention time of the sequence for each gradient slope. This data was used to predict the resolution of the n – 1 impurity among 250 000 random 12- and 16-mer sequences; showing one of the investigated gradient modes has a much higher probability of exceeding a resolution of 1.5, particularly for the 16-mer sequences. Sequences having a high guanine-cytosine content and a terminal C are more likely to not reach critical resolution. The trained SVR models can both be used to identify characteristics of different separation methods and to assist in the choice of method conditions, i.e. to optimize resolution for arbitrary sequences. The methodology presented in this study can be expected to be applicable to predict retention times of other oligonucleotide synthesis and degradation impurities if provided enough training data.

Novel microfabricated solid-contact potentiometric sensors doped with multiwall carbon-nanotubes for simultaneous determination of bisoprolol and perindopril in spiked human plasma

The main concern when developing solid contact ion selective electrodes is the choice of ion sensing membranes while keeping in mind, cost effectiveness, simplicity, potential stability, and reproducibility of results. The main aim of this work is to design microfabricated solid contact ion selective electrodes (SC-ISEs) for the selective determination of bisoprolol (BIS) and perindopril (PER) either in their combined pharmaceutical formulation or simultaneously in human plasma. The obstacle was improving the detection limit of the proposed microfabricated sensors so they can determine the plasma peak concentrations of both drugs. Two factors were considered, namely the addition of ionophores and doping the ion sensing membranes with multiwalled carbon nanotubes (MWCNTs). Four sensors were developed for BIS while two other sensors were developed for PER, and their electrochemical performance was assessed. Selectivity of the sensors was determined in presence of some degradation products, impurities and metabolites of BIS and PER. Doping the ion sensing membranes with MWCNTs proved to interfere with the formation of water layer, resulting in more stable performance. Furthermore, addition of calix[6]arene (CX6) increased the sensitivity in case of BIS sensor. The optimum results for BIS were obtained with ion sensing membrane of potassium tetrakis(4-chlorophenyl)borate, CX6 and MWCNTs. Whereas an ion sensing membrane of tetradodecylammonium bromide and MWCNTs, showed best response in case of PER. The linearity range obtained in case of BIS was 8 × 10−9–1 × 10−2 M with an LOD of 1.74 × 10−9M. While for PER, the linearity range was 1 × 10−8–1 × 10−2 M with an LOD of 9.12 × 10−9 M.

Identification, Characterization, and the Determination of Process-related Impurities in Minodronic Acid Bulk Drug

Background: Minodronic acid (MA) is a third-generation nitrogen-containing heterocyclic bisphosphonate used to treat osteoporosis. In the process of starting materials research and preparation, the key intermediate impurities and degradation impurities have a great impact on the quality control of the drug. Objective: A sensitive, reliable, high-performance liquid chromatography (HPLC) method was developed and validated for the quantitative determination of MA and its related impurities (a total of 6 compounds, including 2 new impurities). Methods: The separation was achieved on an InertSustain ODS-4 C18 (250 mm × 4.6 mm, 5 μm) column using the mixture of 0.01 mol/L sodium pyrophosphate and 1 mmol tetrabutylammonium phosphate (the mobile phase pH was adjusted to 7.80 by phosphonic acid). Results: The quantitative analytical method was fully validated with respect to linearity (r > 0.999), sensitivity (limit of detection < 35 ng/mL), precision, accuracy (the recovery was between 98.7% and 104.2%), and robustness. Six process-related impurities in Minodronic Acid (MA) bulk drug were determined by high-performance liquid chromatography (HPLC). Furthermore, except for two starting materials, other four impurities were identified and characterized as 2-(imidazo[1,2-a] pyridin-3-yl) ethyl acetate (Imp-C), 2-(imidazo [1,2-a] pyridin- 3- yl)acetic acid (Imp-D), 3-(2-hydroxy-2,2- diphosphonoethyl)-4H-imidazo [1,2-a] pyridine -4- oxide (Imp-E) and 2,5- Dihydroxy- 3,6-bis(imidazo[1,2-a] pyridine-3-yl methyl) -2,5-dioxo- 1,4,2,5- dioxoDiphosphonium-3,6-diyl) bisphosphonic acid (Imp-F) using liquid chromatograph- mass spectrometer (LC-MS), MS/MS, Infrared Radiation and Nuclear Magnetic Resonance spectroscopy (1H-NMR and 13C-NMR). To the best of our knowledge, two of them (Imp- E and Imp-F) are new compounds and have not been reported previously. Conclusion: The HPLC method was developed and optimized, which could be applied for quantitative detection of the impurities, and further quality evaluation of MA.

HPLC-PDA identification and resolution of rufinamide forced degradation impurities: A congregated chemometric expedite optimization coupled with factorials and desirability.

Rufinamide is used presently to treat Lenaux-Gastaut syndrome. A full factorial design and desirability approach was investigated for the optimization of hydrolytic stress via response surface curves (RSCs). The degradation impurities were identified and resolved using reversed-phase high-performance liquid chromatography (RP-HPLC) on the Qualisil® BDS C8 column. Acetonitrile-water (29:71, v/v) was optimized for the mobile phase and used at a flow rate of 1.0ml/min with detection at a wavelength of 230 nm. Rufinamide showed appreciable susceptibility to hydrolysis under acidic and alkaline stress, and substantial degradation in the neutral condition. It degraded much less under oxidative stress. Exposure towards thermal and photolytic stress conditions indicated appreciable stability. The developed method was subjected to validation as per the recommendations of the International Conference on Harmonization. The proposed method showed no influence from the excipients and the degradation products. As well as good precision and accuracy in determination, the method showed a linear response between 2 and 12 μg ml-1 . The method was extended for determination in a human plasma sample, which resulted in excellent recovery without interference from matrix effects. The combined use of desirability and design for the optimization of acidic and alkaline hydrolytic stress led to simple and rapid analysis.

DEGRADATION KINETICS OF CARVEDILOL PHARMACEUTICAL DOSAGE FORMS (TABLETS) THROUGH STRESS DEGRADATION STUDY

Objective: The aim of the research work to monitor impurities profiling and degradation kinetics of Carvedilol Pharmaceutical Dosage Form (Tablets) through stress degradation study.
 Methods: To study impurity profiling and degradation kinetics Chromatographic condition used as, Inertsil ODS 3V column (150 mm x 4.6 mm, 5μm) with mobile phase consisting Mobile phase-A (Water, Acetonitrile and Trifluroacetic acid in the ratio of 80:20:0.1 v/v/v respectively and pH adjusted to 2.0 with dilute potassium hydroxide solution) and Mobile phase-B (Water and acetonitrile in the ratio of 100:900 v/v respectively) delivered at flow rate of 1.0 ml min-1 and the detection wavelength 240 nm. The column compartment temperature maintained at 40 °C.
 Results: Stress degradation study conducted using Acid, Alkali, Oxidation, Humidity, Thermal and Photolytic stress degradation conditions. Known, unknown and degradant impurities nature and degradation kinetics in different stressed degradation conditions were monitored through stability indicated method reverse phase HPLC method. Carvedilol molecule found sensitive to Oxidation and Alkali conditions. Impurity-A significantly increased from its not detected level.
 Carvedilol molecule found stable in Acid, Humidity, Thermal and Photolytic stress degradation condition. In all stressed conditions, mass balance was found between 95% to 105% and peak purity of carvedilol peak was found pure.
 Conclusion: Stress degradation study is required to know the degradation pathway of product and to prove the stability indicating nature of the analytical method. Study provide information pertaining to the intrinsic stability of drug product.

Development and Validation of Novel Rapid Stability Indicating Mass Compatible UPLC Method for the Simultaneous Estimation of Assay and Related Substances of Remdesivir in Bulk and Injectable Dosage Form

Developed and validated a simple, rapid, new mass compatible reverse phase ultra-performance liquid chromatography (UPLC) method for the simultaneous estimation of assay and related substance of remdesivir in bulk and injectable dosage form. The developed method is capable of separating all the potential process and degradation impurities within 15 min. Chromatography was carried out using Waters Acquity BEH C18 column (50 mm length, 2.1 mm internal diameter and 1.7 μ particle size) with gradient elution. Ghost buster column (30 mm length, 2.1 mm internal diameter) was used as inline filter to suppress the response of peaks originating from mobile phase. Mobile phase A composed of 10 mM ammonium acetate buffer pH 3.5 and acetonitrile in the ratio of 90:10 v/v and mobile phase B composed of 10 mM ammonium acetate buffer pH 3.5 and acetonitrile in the ratio of 10:90 v/v. The flow rate of the mobile phase was set at 0.35 mL/min and the column temperature was maintained at 35 ºC. The detection was carried out using UV detector at 245 and 270 nm. Method validation was performed according to ICH guidelines. The validated method is simple, rapid, mass compatible, economical, specific, accurate, linear, precise, rugged, sensitive, robust and stability indicating. This method can be employed for the simultaneous estimation of assay and related substance of remdesivir in bulk and injectable dosage forms at quality control laboratories of pharmaceutical industries.

Ibuprofen And Diphenhydramine Citrate Related Substances In Tablet Dosage Form May Be Determined Simultaneously Using A Reversed-Phase High-Performance Liquid Chromatographic Technique

Ibuprofen and diphenhydramine citrate have been combined into one dosage form, and a novel graded reverse-phase elevated HPLC technology has been created for the simultaneous detection of related chemicals in this dosage form. This technique is also capable of detecting degradation products and impurities associated with the manufacturing process. The approach involved the utilization of a C18 column and a mobile phase composed of a gradient mixture of solvent A and B. Moreover, this method is well-suited for the determination of the assay of citrate versions of ibuprofen and diphenhydramine from pharmaceutical sources. Furthermore, the technique is stability-indicating, indicating its suitability for evaluating the shelf-life of pharmaceutical products.

New Stability Indicating Rp-Hplc Method for the Determination of Potential Process Related Impurites and its Degradation Products of Dasatinib and Identification, Isolation and Chracterization of Unknown Acid Degradation Impurity of Dasatinib

New Stability Indicating Rp-Hplc Method for the Determination of Potential Process Related Impurites and its Degradation Products of Dasatinib and Identification, Isolation and Chracterization of Unknown Acid Degradation Impurity of Dasatinib

Chemical stability of naloxone products beyond their labeled expiration dates.

The purpose of this study was to evaluate the chemical stability of previously dispensed, expired naloxone products. When properly stored, certain products maintain stable, defined as within compendia acceptability, beyond their manufacturer's expiration date. Stockpiling life-saving medications such as the opioid overdose reversing agent naloxone nasal spray (NNS) or injection (NIJ) is of utmost importance to ensure public health emergency preparedness and response. Design/interventions/methods: After each naloxone product was stored at room temperature for several months (6-19) past their labeled expiration date, the level of active therapeutic content and the presence of degradation impurity, 2,29'-bisnaloxone, were evaluated via chromatographic separation with waters higher performance liquid chromatography integrated using the Waters X-Select CSHC-18. The effluent was detected at 229 nm. Active naloxone presence and the presence of degradation impurity, 2,29'-bisnaloxone, were evaluated. The mean potency of naloxone in both NNS and NIJ, up to 10 and 19 months post-expiration, respectively, is within the 90-110 percent United States Pharmacopeia acceptance limit (NNS: 102.8 ± 2.6 percent and NIJ: 106.0 ± 1.3 percent). No impurity was detected in any chromatogram of the expired products. In summary, since both NNS and NIJ were found to be chemically stable beyond 10 months of the expiration date, shelf-life extension of climate controlled, commercially available naloxone products should be further investigated as a potential cost savings measure for national strategic stockpiles, emergency medical services, hospitals, and public responders.

USING PREPARATIVE CHROMATOGRAPHY AND NMR/LCMS/FT-IR, ISOLATION, IDENTIFICATION, AND CHARACTERIZATION OF POSACONAZOLE OXIDATIVE DEGRADATION IMPURITIES

Posaconazole is a pharmacological ingredient that is used to treat fungal infections. It comes in the form of delayedrelease tablets. During the forced degradation studies of Tablets, two unknown oxidative degradation impurities were discovered. The impurities were made from Posaconazole using meta-Chloroperoxybenzoic acid as an oxidant in the degradation process. Preparative chromatography was used to separate impurities, and spectroscopic techniques such as IR, NMR, and MS were used to deduce the structures. For the measurement of the total of six associated impurities of Posaconazole in Delayed-Release Tablets, a reverse phase HPLC technique was developed and validated according to ICH Q2 criteria

Characterization of Low-Level D-Amino Acid Degradation Impurities Using Liquid Chromatography-High Resolution Tandem Mass Spectrometry

Characterization of Low-Level D-Amino Acid Degradation Impurities Using Liquid Chromatography-High Resolution Tandem Mass Spectrometry

Using Metabolite Data to Develop Patient Centric Specification for Amide Impurity in Vildagliptin Tablets

Many specified impurities in vildagliptin’s finished product have been disclosed in the literature that are above their qualification threshold. We used the impurity B (amide impurity) as a case example to explore whether existing literature can be leveraged to determine the safe level of impurity and thereby develop a patient-centric specification (PCS) for impurities. No-observed-adverse-effect level (NOAEL) was derived from rate metabolism information and converted to human equivalent dose (HED). The HED was estimated as 6.5 mg/day. The high qualification levels are supported by repeat dose toxicity studies performed in rats, mice and dogs. Maximum theoretical amount (MTA) was correlated with the maximum observed amount (MOA) to verify whether the exposure was due to impurity and/or metabolite. MOA/MTA was found ≥1 suggesting that metabolism contributed to the amount excreted in feces and therefore could be used to further justify a higher specification limit than the usual one of ≤0.5%. Quite often the drug metabolism and degradation pathways overlap, resulting in the formation of identical constituents. Therefore, metabolism data can be leveraged for deriving safe levels of degradation impurities and develop PCS for impurities.

Separation and Characterization of the Related Substances of Bedaquiline Fumarate Using HPLC and Spectral Methods

The study focuses on isolating and characterizing the potential degradation products (DPs) and impurities of Bedaquiline fumarate in bulk drug form. A stability-indicating related substance method was developed and validated using high-performance liquid chromatography. Agilent Poroshell 120EC- C18 (150mm × 4.6mm, 2.7μm) column showed an optimum separation of 10 analytes. The mobile phase contained 0.05% trifluoroacetic acid, acetonitrile and methanol in a time gradient mode. Bedaquiline fumarate was susceptible to acid hydrolysis, oxidation, base hydrolysis and showed three potential DPs, including DP-1, DP-2 and Impurity-8. Degradation products, DP-1 and DP-2, were isolated and characterized by ESI-MS, 1H, NMR and 13C NMR spectroscopy. The developed method was validated according to ICH tripartite guidelines and showed adequate specificity, accuracy and linearity. The limit of detection and limit of quantitation were 0.05 and 0.15μg/mL, respectively.

A simple isocratic LC method for quantification of trace-level inorganic degradation impurities (ferricyanide, ferrocyanide, nitrite, and nitrate) in sodium nitroprusside injection and robustness by quality using design approach.

This study developed and validated a trace-level quantification inorganic impurities method using reversed-phase HPLC and performed the robustness check using quality-by-design approach by varying the multiple factors simultaneously. This method is economical and simple and exhibits its stability-indicating nature [for the determination of ferrocyanide ([Fe(CN)₆]4- ), ferricyanide ([Fe(CN)6 ]3- ), nitrate (NO3 - ), and nitrite (NO2 - )] in sodium nitroprusside (SNP) drug substance and liquid dosage form. Chromatographic separation was achieved using a USP L43 column (ACE PFP, 150×4.6 mm, 3 μm) with a simple isocratic elution. The buffer consists of potassium dihydrogen phosphate (50 mM), tetrabutylammonium hydrogen sulfate (9 mM), and tetrabutylammonium hydroxide (25 mM). The buffer pH was adjusted to 7.2 with tetrabutylammonium hydroxide. The mobile phase was mixed with the buffer and acetonitrile (68:32 v/v). The flow rate was 0.8 mL/min, column temperature was maintained at 30°C, and injection volume was 5.0 μL. The SNP impurities were monitored at 225 nm using a UV detector. Further, the method was validated per the International Council for Harmonisation (ICH) guidelines, and forced degradation studies were carried out under different stress conditions. The detector responses were plotted against concentrations, and correlation was linear (r > 0.999) over the range of 0.8-7.5 μg/mL for ferricyanide; 1.0-37.5 μg/mL for SNP; and 0.2-7.5 μg/mL for ferrocyanide, nitrite, and nitrate. The method repeatability was established for all the impurities with relative standard deviation (%), and the results were found to be less than 2.0.

Efficient Synthesis of Potential Impurities in Levonadifloxacin (WCK 771).

Levonadifloxacin (WCK 771) is a novel broad-spectrum anti-methicillin-resistant Staphylococcus aureus (MRSA) agent recently launched in India. Five process impurities and one degradation impurity were synthesized as reference standards for their quantification by high-performance liquid chromatography (HPLC) methodology in drug substance and drug product. These compounds are not easily commercially available. The synthesis and characterization of these impurities are discussed in detail.

STABILITY INDICATING RP-HPLC METHOD FOR SEPARATION AND QUANTIFICATION OF RELATED SUBSTANCES OF TICLOPIDINE IN BULK AND PHARMACEUTICAL FORMULATIONS

A simple, specific, accurate and stable reverse phase liquid chromatographic method was developed for the simultaneous determination of ticlopidine and its related impurities A and B in bulk drug and tablet dosage forms. The analysis has been performed on XTerra C18 column (250 mm×4.6 mm; 5 µ id) and mobile phase containing of methanol and pH 6.8 phosphate buffer in the ratio of 80:20 (V/V). The detection was carried at 228 nm with a flow rate of 1.0 mL/min. The retention times were found to be 8.9, 5.98 and 4.62 min for ticlopidine, impurities A and B, respectively. The method was validated according to ICH guidelines. The method was validated for specificity, precision, linearity, accuracy and robustness. The linearity range of 50-200 µg/mL for ticlopidine and 0.5-2.0 µg/mL for impurity A and B. The recoveries of ticlopidine and impurities were found to be within the range of 98-102 and the % RSD in each spiked level was found to be less than 2. The stress degradation studies confirmed that the method was effectively separate the degradation products and impurities formed in the stress studies and hence the method was found to be stability indicating method. The method can effectively quantify the standard drug ticlopidine and its impurities A and B in bulk drug and pharmaceutical formulations.

Determination, Isolation, and Identification of Related Impurities in Erdosteine Bulk Drug.

Erdosteine is a mucolytic drug and has antioxidant activity. The study aimed to develop an HPLC method for determination of erdosteine and its impurities in erdosteine bulk drug and to identify the main impurities to help improve the quality of erdosteine bulk drug. The chromatographic separations were performed on a CAPCELL PAK C18 column (250 mm × 4.6 mm id, 5 μm). Acetonitrile-0.01 mol/L citric acid solution (13 + 87, by volume) pumped at a flow rate of 1.0 mL/min was used as the mobile phase. The detection wavelength was 254 nm. Two main impurities in erdosteine bulk drug were enriched by an ODS column chromatography and oxidative degradation, respectively, and then both were purified by semipreparative HPLC. Finally, their structures were identified by a variety of spectral data (MS, 1H NMR and 13C NMR). Good separations of erdosteine and its related impurities were observed. A new impurity was confirmed as ethyl ({2-oxo-2-[(2-oxotetrahydro-3-thiophenyl) amino] ethyl} sulfanyl)acetate, which was erdosteine ethyl ester, and was produced in the refining process of erdosteine bulk drug when using ethanol as a refining solvent. Another impurity was confirmed as ({2-oxo-2-[(2-oxotetrahydro-3-thiophenyl)amino]ethyl}sulfinyl) acetic acid, which was an erdosteine oxide. An HPLC method for determination of erdosteine and its related impurities was developed and validated. Two main impurities in erdosteine bulk drug were isolated and identified. Avoiding ethanol as the refining solvent can improve the purity of erdosteine bulk drug. A new process-related impurity and an oxidative degradation impurity in erdosteine bulk drug were isolated and identified.

A novel stability-indicating method for known and unknown impurities profiling for diltiazem hydrochloride pharmaceutical dosage form (tablets)

BackgroundA novel gradient, high-sensitive and specific stability-indicating reverse-phase HPLC method was developed and validated for quantitative purpose of known, unknown and degradant impurities profiling for diltiazem hydrochloride tablets. The impurities were separated on the Zorbax RX C8 column (150 mm × 4.6 mm, 5 μm) with mobile phase-A consisting of a mixture of 0.05 M sodium dihydrogen phosphate monohydrate buffer pH 3.0 and methanol in the ratio 800:200v/v and mobile phase-B consisting of acetonitrile with a flow rate of 1.0 mL min−1. The column compartment was maintained at 35 °C, and the detection wavelength was 240 nm. Diltiazem hydrochloride, its known impurities and unknown impurities have been well resolved from each other.ResultsThe linearity of the method has been demonstrated across the concentration range of 0.18 to 5.65 µg mL−1 for EP impurity-F with correlation coefficient R2 greater than 0.99. Recovery of method was proved from LOQ to 150% for known and unknown impurities with respect to test concentration and found in between 80 and 120%. Forced degradation study and specificity experiment results with mass balance proved the stability-indicating nature of the method and separated all known, unknown impurities and degradants from each other as well as from main drug component (diltiazem hydrochloride). The mass balance for stress study was found in between 95 and 105%.ConclusionNewly developed analytical method was validated as per ICH Q2 (R1) guidelines “Validation of analytical procedure” and found linear, accurate, specific, robust and precise in the established working range.

A study on structural characterization of potential impurities of Sugammadex sodium using LC/ESI/QTOF/MS/MS and NMR

The first selective relaxant binding agent (SRBA), Sugammadex sodium (SGS) is used to reverse anesthesia. A study of the process related and degradation products will help to optimize process parameters and also to develop the analytical methods and set the quality standard for a quality control strategy in pharmaceutical industry. During the manufacture of SGS, all the process related impurities are controlled in every stage and process related and degradation products are controlled in the active pharmaceutical ingredient (API) as per ICH guidelines. A total of nine process related and degradation impurities of SGS (Impurity-A to Impurity-I) were isolated and characterized by using LC/ESI/QTOF/MS/MS and NMR studies.

The Influence of Supersaturation and the Presence of Biuret on the Nucleation, Growth and Morphology of Urea Crystallised from Ethanolic Solutions

AbstractThe influence of biuret, a degradation impurity, on the crystallisability, nucleation, growth and morphology of urea, is examined as a function of supersaturation in ethanolic solutions, through a combination of polythermal turbidometry assessment and optical microscopy measurements, complemented by molecular modelling.The inclusion of a small amount of impurity is found to increase the stability of supersaturated solutions through widening the metastable zone width. Polythermal analysis of crystallisation and dissolution on‐sets as a function of cooling and heating rate, respectively, is found to be concentration‐dependent associated with both the pure and doped systems, with the nucleation mechanism changing from progressive to instantaneous with increasing solute concentration. The addition of biuret significantly increases nucleation rate when compared to the pure system, from 9.2–20.5 to 9.3–67.7 nm−3 s−1, along with a decrease in the critical nucleus size, as would be consistent with the impurity promoting nucleation i. e. resulting in more nuclei and smaller crystals.The crystal habit of urea in ethanolic solutions is found to be dominated by the prismatic {110} faces, and smaller polar {111} capping faces. The mean crystal growth rates of these faces are found to increase with respect to supersaturation, with the {111} faces exhibiting a greater level of increase than {110}, consistent with stronger solvent binding which restricts the growth of the {110} face. The addition of biuret is found to have a greater effect on retarding the growth of {111} compared to {110}, resulting in a more compact and equant morphology. These results are rationalised with computational visualisation and modelling of the surface chemistry of the crystal habit planes together with the energetics of the impurity binding to them.