Impurities In Active Pharmaceutical Ingredient Research Articles

Mutagenic Azido Impurities in Drug Substances: A Perspective.

Contamination of drug products and substances containing impurities is a significant concern in the pharmaceutical industry because it may impact the quality and safety of medicinal products. Special attention is required when mutagenic impurities are present in pharmaceuticals, as they may pose a risk of carcinogenicity to humans. Therefore, controlling potential mutagenic impurities in active pharmaceutical ingredients to an acceptable safety limit is mandatory to ensure patient safety. As per the International Council for Harmonization (ICH) M7 (R2)3 Guideline, mutagenic impurities are those compounds or materials that induce point mutations. In 2018, the sartan class of drugs was recalled due to the presence of N-nitrosamine impurities, which are potential mutagens. In addition to the primary impurities being detected, this class of products, especially losartan, irbesartan and valsartan, have been identified as having organic azido contaminants, which are again highly reactive toward DNA, leading to an increased risk of cancer. These azido impurities form during the preparation of the tetrazole moiety via the reaction of a nitrile intermediate with sodium azide. Given that this is a newly raised issue in the pharmaceutical world, it should be noteworthy to review the related literature. Thus, this review article critically accounts for (i) the toxicity of azido impurities and the proposed mechanism of mutagenicity, (ii) the regulatory perspective, and (iii) the sources and control strategies used during the preparation of drug substances and (iv) future perspectives.

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.

A Review on The Impurity Profile of Pharmaceuticals

A collection of analytical procedures known collectively as “impurity profiling” are intended to detect, identify, clarify the structure of, and quantify both organic and inorganic impurities as well as residual solvents in pharmaceutical formulations and bulk pharmaceuticals. This is the main task of contemporary drug analysis since it is the most effective approach to describe the stability and quality of pharmaceutical formulations and bulk pharmaceuticals. To keep an eye on them, specific analytical techniques must be created. When modifications are made to the synthesis, formulation, or production processes, even if they are done to improve them, new purities could be seen. The identification of impurities in Active Pharmaceutical Ingredients (APIs) and the need for purity are being emphasised by a number of regulatory bodies, including the Canadian Drug and Health Agency (CDHA), the United States Food and Drug Administration (FDA), and the International Conference on Harmonisation (ICH). Pharmaceutical products can contain impurities from a variety of sources, including reagents, heavy metals, ligands, catalysts and other materials like charcoal, filter aids, and the like. Degraded end products from hydrolysis, photolytic cleavage, oxidative degradation, decarboxylation, and other processes can also contain impurities, as can enantiomeric impurities. The various pharmacopoeias, including the Indian, American, and British pharmacopoeias, are gradually adding restrictions to the permissible concentrations of contaminants found in APIs or formulations. Capillary electrophoresis, electron paramagnetic resonance, gas-liquid chromatography, gravimetric analysis, high performance liquid chromatography, solidphase extraction techniques, liquid-liquid extraction techniques, mass spectrometry, ultraviolet spectrometry, infrared spectroscopy, supercritical fluid extraction column chromatography, nuclear magnetic resonance (NMR) spectroscopy, and RAMAN spectroscopy are some of the techniques used to isolate and characterize impurities in pharmaceuticals. Liquid Chromatography (LC)-Mass Spectroscopy (MS), GC-MS, LC-NMR, LC- NMR-MS, and LC-MS are the most frequently used hyphenated techniques for drug impurity profiling. This demonstrates the importance and range of drug impurity profiling in pharmaceutical research.

Molecularly Imprinted Polymers for Pharmaceutical Impurities: Design and Synthesis Methods.

The safety of a medicinal product is determined by its pharmacological and toxicological profile, which depends not only on the active substance's toxicological properties, but also on the impurities it contains. Because impurities are a problem that must be considered to ensure the safety of a drug product, many studies have been conducted regarding the separation or purification of active pharmaceutical ingredients (APIs) and the determination of impurities in APIs and drug products. Several studies have applied molecularly imprinted polymers (MIPs) to separate impurities in active ingredients and as adsorbents in the sample preparation process. This review presents the design of MIPs and the methods used to synthesise MIPs to separate impurities in APIs and drug product samples, the application of MIPs to separate impurities, and a view of future studies involving MIPs to remove impurities from pharmaceutical products. Based on a comparison of the bulk and surface-imprinting polymerisation methods, the MIPs produced by the surface-imprinting polymerisation method have a higher adsorption capacity and faster adsorption kinetics than the MIPs produced by the bulk polymerisation method. However, the application of MIPs in the analysis of APIs and drug products are currently only related to organic compounds. Considering the advantages of MIPs to separate impurities, MIPs for other impurities still need to be developed, including multi-template MIPs for simultaneous separation of multiple impurities.

PH-Switchable Phase-Transfer Agents for Host Cell Protein Rejection in the Cascaded Biocatalytic Synthesis of an Active Pharmaceutical Ingredient

Given the increased reliance on multienzymatic cascades to synthesize biologically inspired small molecule drug candidates, the pharmaceutical industry requires efficient strategies to control immunogenic protein impurities in active pharmaceutical ingredients. Despite advances in directed enzyme evolution and biocatalysis, it is still economical to use unpurified enzymes overexpressed in host cell lysates in manufacturing processes. Due to similar solubility profiles between protein impurities and the pharmaceutical, separation strategies relying on solubility differences (direct crystallization from water or extraction) often fail. Leveraging the rapid generation of modular acid–base pairs, we describe a pH-responsive extraction strategy using tertiary ammonium phase-transfer agents for efficient purification and isolation of hydrophilic immuno-oncology drug candidate MK-1454 from an aqueous biocatalytic cascade containing crude E. coli cell lysates. We demonstrate this technique to isolate several hundred grams of MK-1454 with undetectable protein impurities for human administration in clinical trials. We further show that this extraction technique is driven by reverse micellization, and may be generally applied to the purification of other hydrophilic small molecules.

Identification and validation of potential genotoxic impurities, 1,3-dichloro-2-propanol, and 2,3-dichloro-1-propanol, at subtle levels in a bile acid sequestrant, colesevelam hydrochloride, using hyphenated GC-MS technique.

Potential genotoxic impurities (PGI) and N-nitrosamine impurities in active pharmaceutical ingredients (APIs) and their determination at low levels are substantial challenges for cholesterol-lowering agents in recent years. Herein we developed a robust, reliable, rapid, accurate and validated technique of gas chromatography equipped with a mass spectrometer (GC-MS) for quantifying subtle levels of 1,3-dichloro-2-propanol (PGI-I) and 2,3-dichloro-1-propanol (PGI-II) in colesevelam hydrochloride drug substance (bile acid sequestrant). The separation of colesevelam hydrochloride, PGI-I and PGI-II was executed with chromatographic technique using a capillary column, DB-624 measuring with 30 m × 0.32 mm × 1.8μm specification of 6% cyanopropylphenyl-94% dimethylpolysiloxane copolymer and helium carrier gas. This developed technique gave a good intensity peak without any interference and extra masses at the retention times of 11.17 min for PGI-I and 11.59 min for PGI-II, which was adequate, with mass spectra (m/z) of 79 and 62, respectively. The method's sensitivity and linearity are demonstrated by its detection and quantification limits at subtle levels with correlation coefficients of 0.9965 for PGI-I and 0.9910 for PGI-II. The determination is mainly focused on improving sensitivity with the limits of detection and quantitation far below the specifications, which can support tighter limits. This results in a cost-effective and easily adoptable methodology having precise and accurate results in colesevelam hydrochloride APIat subtle levels.

Holistic analytical characterization and risk assessment of residual host cell protein impurities in an active pharmaceutical ingredient synthesized by biocatalysts.

Host cell proteins (HCPs) are a significant class of process-related impurities commonly associated with the manufacturing of biopharmaceuticals. However, due to the increased use of crude enzymes as biocatalysts for modern organic synthesis, HCPs can also be introduced as a new class of impurities in chemical drugs. In both cases, residual HCPs need to be adequately controlled to ensure product purity, quality, and patient safety. Although a lot of attentions have been focused on defining a universally acceptable limit for such impurities, the risks associated with residual HCPs on product quality, safety, and efficacy often need to be determined on a case-by-case basis taking into consideration the residual HCP profile in the product, the dose, dosage form, administration route, and so forth. Here we describe the unique challenges for residual HCP control presented by the biocatalytic synthesis of an investigational stimulator of interferon genes proteinagonist, MK-1454, which is a cyclic dinucleotide synthesized using Escherichia coli cell lysate overexpressing cyclic GMP-AMP synthaseas a biocatalyst. In this study, a holistic characterization of residual protein impurities using a variety of analytical tools including nanoscale liquid chromatography coupled to tandem mass spectrometry, together with in silico immunogenicity prediction of identified proteins, facilitated risk assessment and guided process development to achieve adequate removal of residual protein impurities in MK-1454 active pharmaceutical ingredient.

Measurement Uncertainty Estimation for the Quantitative Determination of Elemental Impurities in Active Pharmaceutical Ingredients Using Microwave Digestion Followed by ICP-OES According to USP <232> and <233> Specifications

Measurement Uncertainty Estimation for the Quantitative Determination of Elemental Impurities in Active Pharmaceutical Ingredients Using Microwave Digestion Followed by ICP-OES According to USP <232> and <233> Specifications

A review on benefits of mass spectrometry for the small molecule drug discovery

The drug discovery is a very much time consuming as well as costly procedure. The Mass Spectrometry (MS) technology offers the aptitude for characterization, identification, as well as quantification of a target entity in a complex matrix and has settled into a leading analytical tool in the field of medicinal chemistry and drug discovery. However, by using specific MS-based techniques including personalized sample design, coupling to the gas and liquid chromatography and various ionization techniques, both qualitative as well as quantitative analysis of small molecular drug particles can be obtained. The current review describes MS strategies which are used to enhance and accelerate drug identification besides degradation linked impurities in active pharmaceutical ingredients (API) or articulated products. The level of protein expression is often termed as proteomics research. With use of MS technology, we can learn more reliable as well as dynamic ways of protein analysis. Key words: MS, drug discovery, active pharmaceutical ingredients (API), spectroscopy.

Intrinsic acetamide brush-off by polyurea biodendrimers.

The presence of genotoxic impurities in active pharmaceutical ingredients (APIs) is a major concern for the pharmaceutical industry. Acetamide is a common genotoxic byproduct found in synthetic routes of many APIs, mainly due to acetonitrile hydrolysis, and selective scavenging is a still a challenging task. Herein, as a proof-of-concept, we evaluate polyurea (PURE) biodendrimers as strategic nanopolymers to prepare safe drug nanoformulations from mixtures containing acetamide, using (S)-ibuprofen (IBF) as a model drug. Furthermore, computational molecular dynamics (MD) simulations were conducted to rationalize in vitro results and to identify the key intermolecular interactions within mixtures. Experimental data were corroborated by MD simulations which showed that acetamide, IBF and carboxyfluorescein interactions with PURE biodendrimers are mostly at the surface. Also, PURE nanoformulations appear to be driven by hydrogen bonding, electrostatic and hydrophobic interactions.

Impurity profiling of Cefteram pivoxil based on Fourier transform ion cyclotron resonance MS

Profiling impurities for the active pharmaceutical ingredients (APIs) is an indispensable step in drug development process. Nowadays, high resolution mass spectrometry is the first choice for determining the chemical formula of organic impurities. However, merely base on the accurate mass to screen the formula is obviously not a flawless method. In this paper, a reliable strategy based on Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) was presented to profile the related impurities. Firstly, Cefteram pivoxil was subjected to forced degration under hydrolytic (acidic and basic), oxidative, photolytic and thermal conditions according to ICH guidelines. Then, a highly specific and efficient HPLC-FT-ICR MS compatible method was developed and it was used to separate and characterize the process related substances and the major degradation products in Cefteram pivoxil. Next, isotopic fine structures (IFSs) of all impurities were acquired to decisively determine their elemental composition. Finally, the possible chemical structures of impurities were predicted by combining the information of accurate mass, retention time, IFSs and characteristic fragmentation ions. As a result, a total of 20 related substances including 6 process related substances and 14 degradation products were identified and characterized. To the best of our knowledge, 13 of these related substances were not reported in the previous literature. It indicates that the developed strategy is accurate and standard independent to determine the chemical formulae of organic impurities in APIs. In conclusion, the impurity profiles obtained in this study are critical to the quality control and stability study of Cefteram pivoxil. Moreover, the developed method can be used as a versatile workflow to profile the impurities in APIs in the future, especially for the unknown impurities.

A multi-technique analytical approach for impurity profiling during synthesis: The case of difluprednate

A methodology for the qualitative analysis of a mixture of compounds obtained during the synthesis of difluprednate is described herein for the first time. For this scope a multi-technique analytical approach was developed, combining Liquid Chromatography/Mass Spectrometry (LC/MS), Nuclear Magnetic Resonance (NMR) and computational chemistry. Separation of isomers is frequently required for the identification of impurities in active pharmaceutical ingredients (APIs) to assess the impact they may exhibit on public health. During the final step of the difluprednate synthesis apart from the desired product, various by-products may be obtained. Structural analysis of the products using LC/MS and NMR indicated that the steroid difluprednate was obtained along with its acetyl/butyryl regional isomers, whereas the results were further supported by semi-empirical calculations of the MS-derived data. Following the proposed approach, we managed to elucidate the structures of the challenging 11-acetate, 17-butyrate from the 17-acetate, 21-butyrate, 6α,9α-difluoro prednisolone isomers. The approach utilized may be of general applicability for the analysis of impurities in active pharmaceutical ingredients obtained during chemical synthesis.

Analysis of impurities in pharmaceuticals by LC-MS with cold electron ionization.

Pharmaceuticals require careful and precise determination of their impurities that might harm the user upon consumption. Although today, the most common technique for impurities identification is liquid chromatography-mass spectrometry (LC-MS/MS), it has several downsides due to the nature of the ionization method. Also, the analyses in many cases are targeted thus despite being present, some of the compounds will not be revealed. In this paper, we propose and show a new method for untargeted analysis and identification of impurities in active pharmaceutical ingredients (APIs). The instrument used for these analyses is a novel electron ionization (EI) LC-MS with supersonic molecular beams (SMB). The EI-LC-MS-SMB was implemented for analyses of several drug samples spiked with an impurity. The instrument provides EI mass spectra with enhanced molecular ions, named Cold EI, which increases the identification probabilities when the compound is identified with the aid of an EI library like National Institute of Standards and Technology (NIST). We analyzed ibuprofen and its impurities, and both the API and the expected impurity were identified with names and structures by the NIST library. Moreover, other unexpected impurities were found and identified proving the ability of the EI-LC-MS-SMB system for truly untargeted analysis. The results show a broad dynamic range of four orders of magnitude at the same run with a signal-to-noise ratio of over 10 000 for the API and almost uniform response.

Simultaneous detection of nitrosamines and other sartan-related impurities in active pharmaceutical ingredients by supercritical fluid chromatography

Since July 2018, the pharmacological class of “sartans” has been the subject of considerable media and analytical interest, as it became known that they are contaminated with nitrosamines such as N-nitrosodimethylamine (NDMA), N-nitrosodiethylamine (NDEA) and N-nitrosodiisopropylamine (NDiPA). Previous compendial methods are not able to detect these new contaminants. Using the latest and innovative Quality-by-Design (QbD) approach, it has now been possible to develop an analytical method that enables to investigate sartans, such as valsartan and losartan. Also a large class of different nitrosamines in the ppb range and sartan-related impurities can thus be determined simultaneously in a single analysis using supercritical fluid chromatography (SFC). By using SFC, a broad spectrum of nonpolar and very polar impurities can be separated and analyzed in under 20 min. The analytical method developed is validated for limit testing according to ICH Q2(R1) and fulfills default thresholds of EMA and FDA for testing of drug substances and genotoxic impurities. Additionally, it can also be adapted to other pharmaceuticals that may be contaminated with nitrosamines, since tetrazole synthesis as the underlying cause of nitrosamine contamination is important for a set of other non-sartan drug substances.

Solid State Behavior of Impurities during “In-Process” Phase Purity Analysis of an API

Manufacturing a specified polymorphic form of an active pharmaceutical ingredient (API) is of immense importance in the pharmaceutical industry. Crystal polymorphism and transformations among different forms of APIs are studied in detail during process development. While associated impurities in API are characterized in depth for their chemical structures and properties, solid state characteristics of impurities are usually overlooked, mainly because of their presence in low levels. Herein, we discuss a case of a process impurity, BrettPhos oxide (BPO), interfering with in-process phase analysis of an API. The impact of changing the workup procedure on the impurity purging and its effect on solid form analysis of the API is highlighted. Complexities encountered due to interplay between different solid forms of BPO and API are presented. Further, phase behavior of BPO in some common process relevant solvents is established.

Impurity Identification and Characterization of some Anti-Diabetic Drugs using various Analytical Methods

Various regulatory authorities such as the International Conference on Harmonization (ICH), The United States Food and Drug administration (FDA) are emphasizing on the purity requirements and the identification of impurities in Active Pharmaceutical Ingredients (APIs). Now a day research give great exposure to impurity profiling and forced degradation study of Active pharmaceutical ingredient and combined dosage form used for the treatment of Diabetic. Anti-Diabetic drugs class include: Sulfonylureas, Meglitinides, Thiazolidinediones, Alpha-glucosidases inhibitor, Dipeptidyl-peptidase-4 (DPP-4) inhibitors, Glucagon-like peptide-1 (GLP-1) agonist, Sodium glucose co-transporter 2 (SGLT2) inhibitors. As per ICH, Impurity profiling description of the identified and unidentified impurities present in a typical batch of API produced by a specific controlled production process. There are number of Spectroscopic method like UV(Ultraviolet Spectrometry), MS(Mass spectrometry), IR (infrared spectroscopy), NMR(Nuclear magnetic resonance) and Chromatographic methods identification and better resolution between impurities having near to similar structure with each other or with APIs like Liquid Chromatography (LC)-Mass Spectroscopy (MS), LC-NMR, LC-NMR-MS, GC-MS, and LC-MS. This leads interest of impurity profiling in pharmaceuticals.

Application of hydrophilic interaction liquid chromatography for the quantification of succinylcholine in Active Pharmaceutical Ingredient and medicinal product. Identification of new impurities of succinylcholine chloride

A new method, using hydrophilic interaction chromatography (HILIC), for quantification of succinylcholine and impurities in Active Pharmaceutical Ingredient (API), as well as in the medicinal product, was developed. Additionally, the new impurities in API were discovered using ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-QTOF) technique. The substances were quantified with the application of a UV detector (λ = 214 nm). Chromatographic separation was performed isocratically with the application of 30% phosphate buffer (pH 4,0; 0.05 M) in ACN as a mobile phase. A major feature of the developed method is a very high resolution (Rs > 3), between succinylcholine and its main impurity - succinylmonocholine, whereas the width of peak bands does not exceed 0.7 min. A low value of limits of detection (LOD) were obtained for succinic acid, succinylmonocholine and for succinylcholine, which amounted to 2.4, 6.0 and 11.5 μg ml−1, respectively. Another feature of the developed method is linearity in a very wide range of concentrations: 7.3 μg ml−1 – 670 μg ml−1 amounting to R2 = 0.999. The recovery provided by this method at three different fortification levels for all analytes remained within the following range: 95.7 – 98.9 %. Intra-day and inter-day precision remained within the following range: 1.0 – 5.9 % coefficient of variation (CV), whereas accuracy within the range: −1.3 – 6.3. The developed method of hydrophilic interactions made it possible to quantify two new impurities, probably originating from the synthesis of an API: [2-(trimethylaminium)ethyl]-[2ʹ-(trimethylaminium)vinyl] succinate and [2-(dimethylamino)etyl]-[2ʹ-(trimethylaminium)etyl] succinate, which were identified and described for the first time. In addition, a physicochemical form of peak doublet described in the USP as impurities was studied and it was demonstrated that these peaks are the result of the specific physicochemical interactions in ion pair chromatography.

Development and validation of ultra-performance liquid chromatography method for the determination of meloxicam and its impurities in active pharmaceutical ingredients

The main objective was to develop a suitable and rapid ultra-performance liquid chromatography (UPLC) method for the quantitative determination of meloxicam and its impurities. Starting from data in literature, we calculated the new parameters to translate a high performance liquid chromatography method used for the analysis of meloxicam with its major degradation products to UPLC method, and then we switched on many trials to optimize and improve its analytical performance. Chromatographic separation was achieved on ACQUITY UPLC HSS-T3 (2.1×100mm, 1.8μm). The eluted compounds were monitored at 260nm and 350nm. The flow rate was set at 0.4mL/min, injection volume at 0.8μl, and the column oven temperature was maintained at 45°C. The developed method was validated according to the International Conference on Harmonisation (ICH) guidelines for specificity, linearity, accuracy, precision, robustness, quantification limit, detection limit; and then applied to stability study of meloxicam subjected to different ICH prescribed stress conditions (hydrolysis, oxidation, heat and photolysis). The results show that the new UPLC method enables separation of meloxicam from its impurities in only 5min with a total mobile phase consumption of 1.8mL. All impurities get separated with good peak shapes and resolution factor greater than 2. The new method indicates stability and proved to be specific, precise accurate with linear correlation between concentrations and peak areas, allowing gain of more than six times analysis and more than twenty times solvent consumption, so in cost. Therefore, it can be beneficial for pharmaceutical industrial output.

Intended high-performance liquid chromatography procedure for the quantification of norfloxacin and its potential impurities in active pharmaceutical ingredient and tablet dosage forms

Intended high-performance liquid chromatography procedure for the quantification of norfloxacin and its potential impurities in active pharmaceutical ingredient and tablet dosage forms

Potential Impurities of the Anti-epileptic Drug, Clobazam: Synthesis and Characterization

Background: Clobazam (CLB) has been used as an anxiolytic, anticonvulsant and antiepileptic drug under the trade names, Frisium, Urbanol, Onfi and Tapclob. Impurity profiling in the pharmaceutical industries is a central task in the manufacturing of drug product. The quantification of impurities in active pharmaceutical ingredients (APIs) is also receiving considerable importance from the regulatory authorities in the point of stringent quality requirement. Thus, the provision of substantial quantity of impurities as standards, which are accomplished either by isolation from crude reaction mass or the synthesis of material with proposed structure using new synthetic route, to analytical method development and validation is a good demand. Therefore, easily accessible synthetic routes to the preparation of impurities with the lowest cost are sought after. To date, no synthetic specifics were found on the synthesis and characterization of CLB Imp-B, -C, -D and –F, and the synthesis of CLB Imp-E. Therefore, the comprehensive study was undertaken on the synthesis and characterization of CLB related impurities and this study might be useful to prepare CLB impurities in the required quantity with purity to use as a reference standard of analytical method development in pharmaceutical industry. Methods: The synthetic routes were developed for the synthesis of CLB impurities such CLB Imp-B to Imp-F and isolated them using purification techniques with purity in the required quantity. The commercially available key starting materials, reagents and solvents were used in the course of synthesis of impurities. The analytical techniques such as NMR, IR and mass were used to characterize the structure of synthesized CLB related impurities. Results: The easy accessible synthetic methods were developed for the synthesis of clobazam related impurities, CLB Imp-B to F in good to excellent yields with purity as well as described the cause to formation of these impurities. The KSM related impurity, 2-chloro-1-nitrobenzene and the active methylene hydrogens in clobazam are caused to the formation of CLB Imp-B and CLB Imp-C&-D, respectively. CLB Imp-E and –F are formed due to the degradation of drug molecule, CLB in the presence of base (NaOH). CLB Imp-B was prepared from 2-chloro-1-nitrobenzene by following similar process of CLB reported in the synthetic specific. CLB Imp-F was prepared from 5-chloro-N1 -phenylbenzene-1,2-diamine by coupling with mono-methyl malonate followed by N-methylation using dimethyl sulfate. The rest of all impurities were planned to prepare by taking CLB as starting material. CLB Imp-C and –D were synthesized by treating CLB with methyl iodide in the presence of inorganic base. The mixture of aqueous NaOH and CLB was agitated vigorously at 75-80°C to obtain CLB Imp-E. All the synthesized compounds were purified using purification techniques such as crystallization and column chromatography, and well characterized by IR, ESI-mass, 1H NMR, 13C NMR and DEPT analyses. Conclusion: The immaculate discussion about synthetic approaches and structural elucidation using analytical applications such as IR, NMR (1H, 13C and DEPT) of CLB Imp-B to F, which are listed in the European pharmacopoeia monograph of clobazam, has been described. All the impurities were obtained with stringent purity (>98%) in the described synthetic routes and the same impurities have been used in analytical method development in our pharmaceutical industry. Also, the plausible mechanistic path ways to the formation of impurities, keeping in view the regulatory importance of clobazam, were discussed in detail. Keywords: APIs, clobazam, characterization, EP impurities, synthesis, NMR.