Development and Validation of a Customized Amplex UltraRed Assay for Sensitive Hydrogen Peroxide Detection in Pharmaceutical Water.

For clean-room technologies such as isolators and restricted access barrier systems (RABS), decontamination using hydrogen peroxide (H2O2) is increasingly attractive to fulfill regulatory requirements. Several approaches are currently used, ranging from manual wipe disinfection to vapor phase hydrogen peroxide (VPHP) or automated nebulization sanitization. Although the residual airborne H2O2 concentration can be easily monitored, detection of trace H2O2 residues in filled products is rather challenging. To simulate the filling process in a specific clean room, technical runs with water for injection (WfI) are popular. Thus, the ability to detect traces of H2O2 in water is an important prerequisite to ensure a safe and reliable use of H2O2 for isolator or clean room decontamination. The objective of this study was to provide a validated quantitative, fluorometric Amplex UltraRed assay, which satisfies the analytical target profile of quantifying H2O2 in WfI at low nanomolar to low micromolar concentrations (ppb range) with high accuracy and high precision. The Amplex UltraRed technology provides a solid basis for this purpose; however, no commercial assay kit that fulfills these requirements is available. Therefore, a customized Amplex UltraRed assay was developed, optimized, and validated. This approach resulted in an assay that is capable of quantifying H2O2 in WfI selectively, sensitively, accurately, precisely, and robustly. This assay is used in process development and qualification approaches using WfI in H2O2-decontaminated clean rooms and isolators.

Compatibility and stability of ademetionine 1,4-butanedisulfonate injection mixed with fructose and glucose diluents and pilot study of long-term storage impurities by LC-MS/MS.

Fructose injection is occasionally used to dilute ademetionine 1,4-butanedisulfonate injection for patients who cannot receive glucose or sodium chloride injections in clinical settings. Since our PIVAS staff reported that discoloration occurred after ademetionine 1,4-butanedisulfonate dissolved with fructose injection, this study aims to investigate the stability of ademetionine 1,4-butanedisulfonate in fructose and glucose solutions. Ademetionine 1,4-butanedisulfonate was purchased and diluted with fructose or glucose injection for compatibility testing. The solutions were maintained under various conditions for different periods of time, after which the concentration of ademetionine 1,4-butanedisulfonate and other impurities was analyzed. The chemical structures of unknown impurities were further investigated by liquid chromatography-tandem mass spectrometry. The analytical method was validated and was deemed to be suitable for the analyses in this study. Compatibility tests indicated that ademetionine 1,4-butanedisulfonate is sensitive to temperature, illumination, and pH. When diluted with fructose or glucose, the concentration of ademetionine 1,4-butanedisulfonate decreased over time. The contents of impurities increased accordingly. Additionally, an unknown impurity was identified, speculated to be a hydroxyl oxidation product of ademetionine based on the LC-MS/MS results. Both fructose and glucose injections can be used as diluents for ademetionine 1,4-butanedisulfonate, and the resulting mixture remains stable for up to 8 h after preparation.

Deuterated Drugs: Isotope Distribution and Impurity Profiles.

A recent review identified the problem of lower isotopologues in deuterated active pharmaceutical ingredients (APIs) as a critical issue in this area of medicinal chemistry. In this Perspective, the relationship between overall enrichment and isotope distribution for deuterated APIs is discussed. Deuterated APIs are divided into single deuterium, methyl-d3, and polydeuterated compounds. For the latter category, distribution calculations demonstrate that the parent deuterated API contains significant quantities of the lower isotopologues. As an alternative to the use of overall enrichment to describe these compounds, it is suggested that describing these compounds with a distribution profile should be preferred, giving an accurate and defensible description of the API. Using this approach, the lower isotopologues become an integral part of the API and not an impurity.

Safety assessment of drug impurities for patient safety: A comprehensive review.

Drug impurities are undesirable but unavoidable chemicals which can occur throughout the drug life cycle. The safety implications of drug impurities can be significant given that they can impact safety, quality, and efficacy of drug products and that certain drug impurities are mutagenic, carcinogenic, or teratogenic. The characteristics of drug impurities could be specific to drug modalities (e.g., small molecules vs. biologics). The commonly encountered drug impurities include elemental impurity, residual solvent, organic impurity, host cell protein and DNA, residual viral vector, extractable and leachable, and particle. They can cause various adverse effects such as immunogenicity, infection, genotoxicity, and carcinogenicity upon significant exposure. Therefore, the effective control of these drug impurities is central for patient safety. Regulations and guidelines are available for drug developers to manage them. Their qualification is obtained based on authoritative qualification thresholds or safety assessment following the classic toxicological risk assessment. The current review focuses on the safety assessment science and methodology used for diverse types of drug impurities. Due to the different nature of diverse drug impurities, their safety assessment represents a significant challenge for drug developers.

High-Performance Liquid Chromatography-Tandem Mass Spectrometry Method Development and Validation for Simultaneous Determination of Seven Nitrosamine and Azidomethyl-Biphenyl-Tetrazole Impurities in Losartan.

Nitrosamine-related impurities (N-nitrosomethylamino butyric acid [NMBA], N-nitrosodiethylamine [NDEA], N-nitrosodiisopropylamine [NDIPA], N-nitrosomethylphenylamine [NMPA], N-nitrosodibutylamine [NDBA], N-nitrosodimethylamine [NDMA], and N-nitrosoethylisopropylamine [NEIPA]) and 5-[4'-(azidomethyl)-[1,1'-biphenyl]-2-yl]-2H-tetrazole (AZBT) formed during the manufacture of sartan medicines have been classified into human mutagens and carcinogens after long-term treatment. The study developed a simple, economical but highly sensitive procedure for the simultaneous quantification of seven nitrosamines and AZBT impurities in sartan pharmaceuticals. After extraction with methanol (MeOH) 50%, the compounds were analyzed with a reversed-phase liquid chromatography-tandem mass spectroscopy with atmospheric-pressure chemical ionization (APCI) mode (APCI[+] for nitrosamines and APCI[-] for AZBT), selected reaction monitoring, C18 column, gradient elution with 0.1% formic acid in water and in MeOH, respectively. The validated procedure obtained high extraction efficiency (>90%), wide linear range (0.2-50.0 ng/mL NMBA, NDEA, NDIPA, NMPA, and NDBA; 0.5-50.0 ng/mL NDMA and NEIPA; 2.0-100 ng/mL AZBT), limit of quantification < 10% of the acceptance level, recovery range of 85%-115% with relative standard deviation < 15% and minimum matrix effects for all impurities. The procedure was applied to test 16 commercial losartan samples. As a result, eight samples contained AZBT within the current regulatory limits, but no nitrosamine impurities were detected in all samples.

Impact of Manufacturing Process and Compounding on Properties and Quality of Follow-On GLP-1 Polypeptide Drugs.

PURPOSE: The prevalence of follow-on and compounded products of glucagon-like peptide-1 analogs is increasing. We assessed glucagon-like peptide-1 analogs semaglutide and liraglutide for purity, potential immunogenicity, and expected stability, by comparing a representative selection of commercially available follow-on drug substances (DSs) and drug products (DPs) with their corresponding originators. METHODS: Tests included several chromatography methods coupled with ultraviolet and mass spectrometry detectors, inductively coupled plasma optical emission spectroscopy, inductively coupled plasma mass spectrometry, nuclear magnetic resonance, dissolution analyses, in silico peptide/major histocompatibility complex II-binding prediction, and fibrillation assays. RESULTS: Overall, 16 injectable semaglutide, 8 oral semaglutide, and 2 injectable liraglutide follow-on products were analyzed alongside originator products. Compared with originator, follow-on injectable semaglutide DSs and DPs had new impurities and impurity patterns, including high molecular weight proteins, trace metals, anions, counterions, and residual solvents. Analyses showed that several commercialized follow-on oral semaglutide DPs had a markedly lower quantity of semaglutide than the label claim, while dissolution tests indicated different semaglutide and sodium N-(8-[2-hydroxybenzoyl] amino)caprylate (SNAC) release profiles, which may reduce bioavailability. Neoepitopes were identified in DS and DP semaglutide follow-ons, indicating potential immunogenicity. Fibrillation assays showed increased fibrillation tendency and reduced physical stability in liraglutide follow-on DP samples compared with originator. CONCLUSION: This study highlights that differences in the manufacturing processes of follow-on semaglutide and liraglutide (vs those used for originators) can result in several changes to the DSs and DPs. The impact of these changes on efficacy and safety outcomes remains unknown and should be investigated by clinical studies.

Misrepresentation of MDMA in the United States, 1999-2023.

BACKGROUND AND AIMS: The misrepresentation of illicit drugs in unregulated markets increases the risk of adverse health events. This study analyzed drug checking data to compare represented, expected, and actual content of alleged MDMA samples, estimate trends in the quality of the MDMA supply, document the presence of adulterants, compare patterns of adulteration, and validate drug checking against law enforcement data. METHOD: The study analyzed 4719 alleged MDMA samples submitted to the DrugsData drug checking service between 1999-2023. Measures captured characteristics and quality of the MDMA supply, including represented content, expected and actual content, sample form, and specific adulterants. Tests of association were conducted using Pearson's chi-square or Spearman's rho, and tests for trends were performed using joinpoint regression. FINDING: Most samples (75 %) were expected to contain MDMA, but this varied significantly by represented content (p<0.001). About half the samples (48 %) contained MDMA-only, which also varied significantly by represented content (p<0.001). MDMA-only prevalence declined from 1999-2009 (57.4-15.2 %, p<0.05), recovered from 2009-2017 (15.2-56.0 %, p<0.05), and increased more moderately from 2017-2023 (56.0-74.1 %, p<0.05). Overall, 199 unique adulterants were detected in the MDMA supply across 25 years. We confirmed robust correlations in adulterant prevalence trends between drug checking and law enforcement seizure data. CONCLUSIONS: While users typically expected alleged MDMA samples to contain only MDMA, more than half of the submitted MDMA samples were misrepresented in some manner. Despite high levels of misrepresentation, MDMA quality has stabilized at relatively high levels in recent years.

Detection of host cell microprotein impurities in antibody drug products.

Chinese hamster ovary (CHO) cells are used to produce almost 90% of therapeutic monoclonal antibodies (mAbs) and antibody fusion proteins (Fc-fusion). The annotation of non-canonical translation events in these cellular factories remains incomplete, limiting our ability to study CHO cell biology and detect host cell protein (HCP) impurities in the final antibody drug product. We utilised ribosome footprint profiling (Ribo-seq) to identify novel open reading frames (ORFs) including N-terminal extensions and thousands of short ORFs (sORFs) predicted to encode microproteins. Mass spectrometry-based HCP analysis of eight commercial antibody drug products (7 mAbs and 1 Fc-fusion protein) using the extended protein sequence database revealed the presence of microprotein impurities. We present evidence that microprotein abundance varies with growth phase and can be affected by the cell culture environment. In addition, our work provides a vital resource to facilitate future studies of non-canonical translation and the regulation of protein synthesis in CHO cell lines.

Simultaneous detection of multiple mycotoxins in Radix Dipsaci and estimation of exposure risk for consumers.

Like many traditional Chinese herbal medicines, preparations from Radix Dipsaci are at risk of contamination by harmful mycotoxins; however, there have been no reports of actual contamination. In this study, we developed an analytical method to simultaneously detect eight mycotoxins in Radix Dipsaci and estimate the exposure risk for consumers. We have developed an analytical method utilizing ultra-high performance liquid chromatography and tandem mass spectrometry to accurately determine the levels of AFB1, AFB2, AFG1, AFG2, OTA, ZEN, T-2 and ST mycotoxins in 45 batches of Radix Dipsaci sourced from major medicinal herb markets across five regions in China. We also analyzed migration of mycotoxins from the raw herbs into water decoction. Based on these results and data on human consumption of the herbal medicine, we estimated risk of exposure and acceptable exposure limits to mycotoxins in the Radix Dipsaci using the "margin of exposure (MOE)" method. Of the 45 batches of Radix Dipsaci, 48.89% contained at least one of the eight mycotoxins, 24.44% contained one, 17.78% contained two and 6.67% contained three. The most frequent mycotoxins were aflatoxin B1, present in 35.56% of batches (at 0.25-34.84 µg/kg); aflatoxin G1, 15.56% (1.99-44.05 µg/kg); and ochratoxin A, 22.22% (16.11-143.38 µg/kg). These three mycotoxins transferred from the raw herb into water decoction at respective rates of 20.20%, 29.14%, and 24.80%. The 95th percentile values of the MOE risk factors for health effects of AFB1 were below 10,000 at high doses but above 10,000 at low doses of Radix Dipsaci long-term treatment. With the reduction in duration of exposure years, the MOE values of AFB1 and AFG1 gradually reverted to within the acceptable range. The mean, 50th, and 95th percentile values of the MOE risk factors for health effects of OTA exceeded 10,000 regardless of whether consumers received a low or high dose of Radix Dipsaci treatment for durations ranging from 1 to lifetime. Based on this exposure and a typical human diet, we have estimated the respective 20-year exposure limits for Radix Dipsaci to be 5.821 µg/kg, 4.035 µg/kg, and 56.073 µg/kg for the three mycotoxins under consideration. Contamination with multiple mycotoxins is frequently observed in Radix Dipsaci, and the three most prevalent contaminants have been found to leach into water decoctions, thereby posing a potential health hazard for individuals consuming this herbal preparation. This work highlights the need to monitor herbal medicines for mycotoxin contamination in order to protect consumers.

Robustness evaluation of weak anion exchange chromatography method for the purity analysis of therapeutic oligonucleotides.

Therapeutic oligonucleotides are becoming an important class of therapeutics. Their manufacturing processes can result in the formation of impurities, particularly truncated species. To ensure the quality and safety of the product, it is crucial to evaluate the presence of these species. Liquid chromatography analysis enables such purity determination. In this context, a recently described weak anion exchange chromatography method was optimized to allow the effective separation of different impurities. The optimization addressed the complexity and instability of the mobile phases, which contained salts and organic compounds. Adjustments were made to the mobile phase composition and gradient to meet the requirements of QC laboratories. Additionally, to ensure the method's reliability, a robustness study was conducted based on a risk assessment. Five factors were considered potential risks and were assessed experimentally on different chromatographic outputs. This led to the definition of a robust space, ensuring the method's reliability for the purity determination of oligonucleotides.

Economical and rapid enantioselective, diastereoselective and achiral separation of palonosetron hydrochloride and its impurities using supercritical fluid chromatography.

Simultaneous separation of compounds with multiple chiral centers and highly similar structures presents significant challenges. This study developed a novel supercritical fluid chromatography (SFC) method with reduced organic solvent consumption and robust separation capabilities to address these challenges. The method was applied to simultaneously achieve enantioselective, diastereoselective, and achiral separation of palonosetron hydrochloride and its six impurities. The effects of the polysaccharide-based chiral stationary phase (CSP), modifier, additive, and column temperature on retention and separation were comprehensively evaluated. It was found that a combination of a polysaccharide-based CSP and a single modifier or a mixture of protonic modifiers could not achieve complete separation due to high structural similarity. However, an ADH column and a ternary solvent mixture containing acetonitrile (methanol: acetonitrile: diethylamine, 60:40:0.2, v/v/v) provided satisfying separation, particularly for the enantiomer and diastereomers of palonosetron. Using the optimized method, the enantioselective, diastereoselective, and achiral separation of palonosetron hydrochloride and its six impurities can be accomplished in 18 min under gradient elution. Thermodynamic results indicated that the separation process was entropy driven. A molecular docking study revealed that the separation was mainly achieved through the differences in hydrogen bond and π - π interactions between the analytes and CSP. This study lays the foundation for SFC analysis of palonosetron hydrochloride and provides a reference for the simultaneous SFC separation of the enantiomers, diastereoisomers and structurally similar compounds.

Hydrophobic interaction chromatography in continuous flow-through mode for product-related variant removal.

Product-related impurities are challenging to remove during monoclonal antibody (mAb) purification process due to molecular similarity. Frontal chromatography on hydrophobic interaction resins has demonstrated its capability to effectively remove such impurities. However, process improvements geared towards purity level comes as a trade-off with the yield loss. In this work, we present a hydrophobic interaction chromatography process using multicolumn continuous chromatography (MCC) concept and frontal analysis to remove a high prevalence product related impurity. This design uses a two-column continuous system where the two columns are directly connected during product chase step to capture product wash loss without any in-process adjustment. This polish MCC operation resulted in a 10 % increase in yield while maintaining 99 % purity, despite the presence of 20 % product-related impurities in the feed material. One challenge associated with polish MCC design is that the accumulation of the impurities renders a non-steady state recycling. To surmount this issue and ensure a robust process, a mechanistic model was developed and validated to predict multicomponent breakthrough. This model was capable to predict multiple cycle behavior and accounts for increased impurity concentration. Assisted by the model, the optimized operation parameters and conditions can be determined to account for variation in product load quality. The simulated results demonstrate an effective doubling of productivity compared to conventional batch chromatography.

A practical HPLC-MS method for the analysis of nitrosamine drug substance related impurities using an inexpensive single quadrupole mass spectrometer.

Nitrosamine drug substance related impurities (NDSRIs) are often analyzed using high performance liquid chromatography (HPLC) with mass spectrometry (MS) detection. Due to high sensitivity requirements, high resolution MS or MS/MS is commonly used. However, it is difficult to implement this type of method for routine analysis at a supply site. Herein, we report a systematic approach to develop and validate a practical, robust, and user-friendly method for the analysis of NDSRIs using an inexpensive single quadrupole MS instrument such as QDa. We used 7-nitroso-3-(trifluoromethyl)-5,6,7,8-tetrahydro- [1,2,4] triazolo [4,3-a] pyrazine (NTTP) as an example to demonstrate the method development process. By optimizing the HPLC and MS parameters, we were able to develop a simple HPLC-MS method that provides the desired specificity and sensitivity for the analysis of NTTP and can be easily implemented in an analytical lab. The limit of quantitation is 0.5 ng/mL, corresponding to 0.1 ppm with respect to 5 mg/mL sitagliptin. The method has been successfully validated per ICH guidelines.

Development, evaluation of critical method variables and stability assessment using a Box-Behnken design for the determination of organic impurities in a pharmaceutical dosage form of a centrally acting muscle relaxant drug chlorzoxazone.

This study validates a stability-indicating LC method for detecting organic impurities in the chlorzoxazone dosage form. Using a Waters X-Select R HSS T3 analytical column, mobile phase of it was made by mixing of water, methanol, and glacial acetic acid in the ratio of 700:300:10 (v/v/v). The drug product and drug substance were subjected to the stress conditions such as acid, base, oxidation, heat, and photolysis as per the recommendations of the International Conference on Harmonization (Q2) methodology. The study revealed the susceptibility of 4-chloro-2-aminophenol to alkaline environments, emphasizing peak homogeneity and stability. The method verification, per ICH guidelines and USP<1225>, established precision, specificity, linearity, accuracy, and robustness for quality control. The mean impurity recovery ranged from 95.5% to 105.2%, the correlation coefficient (r) was greater than 1.000, and the RSD values (n = 6) ranged from 0.6% to 5.1% across the LOQ-150% ranges. Full-factorial design tested final method conditions, evaluating multiple parameters concurrently. Graphical optimization within the design space defined strong method requirements, ensuring consistent and reliable outcomes. The study develops and validates chlorzoxazone stability-indicating methods, employing advanced statistical approaches like design of experiments and factorial design, with resilient conditions established through graphical optimization of the design space.

Optimizing the detection of N-nitrosamine mutagenicity in the Ames test.

Accurately determining the mutagenicity of small-molecule N-nitrosamine drug impurities and nitrosamine drug substance-related impurities (NDSRIs) is critical to identifying mutagenic and cancer hazards. In the current study we have evaluated several approaches for enhancing assay sensitivity for evaluating the mutagenicity of N-nitrosamines in the bacterial reverse mutagenicity (Ames) test. Preincubation assays were conducted using five activation conditions: no exogenous metabolic activation and metabolic activation mixes employing both 10% and 30% liver S9 from hamsters and rats pretreated with inducers of enzymatic activity. In addition, preincubations were conducted for both 60 min and 30 min. These test variables were evaluated by testing 12 small-molecule N-nitrosamines and 17 NDSRIs for mutagenicity in Salmonella typhimurium tester strains TA98, TA100, TA1535, and TA1537, and Escherichia coli strain WP2 uvrA (pKM101). Eighteen of the 29 N-nitrosamine test substances tested positive under one or more of the testing conditions and all 18 positives could be detected by using tester strains TA1535 and WP2 uvrA (pKM101), preincubations of 30 min, and S9 mixes containing 30% hamster liver S9. In general, the conditions under which NDSRIs were mutagenic were similar to those found for small-molecule N-nitrosamines.

Safety assessment of protein A and derivation of a parenteral health-based exposure limit.

Protein A (PA) is a bacterial cell wall component of Staphylococcus aureus whose function is to bind to Immunoglobulin G (IgG). Given its ability to bind IgG as well as its stability and resistance to harsh acidic and basic cleaning conditions, it is commonly used in the affinity chromotography purification of biotherapeutics. This use can result in levels of PA being present in a drug product and subsequent patient exposure. Interestingly, PA was previously evaluated in clinical trials as well as supporting nonclinical studies, resulting in a database that enables the derivation of a health-based exposure limit (HBEL). Given the widespread use of PA in the pharmaceutical industry, the IQ DruSafe Impurities Safety Working Group (WG) evaluated the available information with the purpose of establishing a harmonized parenteral HBEL for PA. Based on this thorough, collaborative evaluation of nonclinical and clinical data available for PA, a parenteral HBEL of 1.2 µg/kg/dose (60 µg/dose for a 50 kg individual) is expected to be health protective for patients when it is present as an impurity in a biotherapeutic.

Escaping the cohort of concern: in vitro experimental evidence supports non-mutagenicity of N-nitroso-hydrochlorothiazide.

In recent years, nitrosamine impurities in pharmaceuticals have been subject to intense regulatory scrutiny, with nitrosamine drug substance-related impurities (NDSRIs) treated as cohort of concern impurities, regardless of predicted mutagenic potential. Here, we describe a case study of the NDSRI N-nitroso-hydrochlorothiazide (NO-HCTZ), which was positive in the bacterial reverse mutation (Ames) test but is unstable under the test conditions, generating formaldehyde among other products. The mutagenic profile of NO-HCTZ was inconsistent with that expected of a mutagenic nitrosamine, exhibiting mutagenicity in the absence of metabolic activation, and instead aligned well with that of formaldehyde. To assess further, a modified Ames system including glutathione (3.3 mg/plate) to remove formaldehyde was developed. Strains used were S. typhimurium TA98, TA100, TA1535, and TA1537, and E. coli WP2 uvrA/pKM101. In this system, formaldehyde levels were considerably lower, with a concomitant increase in levels of S-(hydroxymethyl)glutathione (the adduct formed between glutathione and formaldehyde). Upon retesting NO-HCTZ in the modified system (1.6-5000 µg/plate), a clear decrease in the mutagenic response was observed in the strains in which NO-HCTZ was mutagenic in the original system (TA98, TA100, and WP2 uvrA/pKM101), indicating that formaldehyde drives the response, not NO-HCTZ. In strain TA1535, an increase in revertant colonies was observed in the modified system, likely due to a thiatriazine degradation product formed from NO-HCTZ under Ames test conditions. Overall, these data support a non-mutagenic designation for NO-HCTZ and demonstrate the value of further investigation when a positive Ames result does not align with the expected profile.

Identification and Activity Study of an Impurity Band Observed in the nrSDS-PAGE of Aflibercept.

BACKGROUND: Aflibercept is a biopharmaceutical targeting vascular endothelial growth factor (VEGF) that has shown promise in the treatment of neovascular age-related macular degeneration (nAMD) and diabetic macular edema (DME) in adults. Quality control studies of aflibercept employing non-reduced SDS-PAGE (nrSDS-PAGE) have shown that a significant variant band (IM1) is consistently present below the main band. Considering the quality control strategy of biopharmaceuticals, structural elucidation and functional studies are required. METHODS: In this study, the variant bands in nrSDS-PAGE were collected through electroelution and identified by peptide mass fingerprinting based on liquid chromatography-tandem MS (LC-MS/MS). This variant was expressed using knob-into-hole (KIH) design transient transfection for the detection of ligand affinity, binding activity and biological activity. RESULTS: The variant band was formed by C-terminal truncation at position N99 of one chain in the aflibercept homodimer. Then, this variant was successfully expressed using KIH design transient transfection. The ligand affinity of the IM1 truncated variant was reduced by 18-fold, and neither binding activity nor biological activity were detected. CONCLUSIONS: The efficacy of aflibercept is influenced by the loss of biological activity of the variant. Therefore, this study supports the development of a quality control strategy for aflibercept.

Aspects of complexity in quality and safety assessment of peptide therapeutics and peptide-related impurities. A regulatory perspective.

In recent years, a number of therapeutic peptides have been authorized in the EU market, and several others are in the clinical development phase or under assessment for full dossier or generic applications. Quality and safety guidelines specific to peptides are limited, and some aspects have to be considered. In particular, concerns relate to the analytical investigation for impurities and the toxicological assessment of these substances. The guidelines and the compendial pharmacopoeias provide certain references but that may be questionable if interpreted according to whether therapeutic peptides are considered chemical or biological entities, large or small. The characterization of peptide-related impurities cannot follow the small molecule approach but should consider aspects closely linked to the complex mechanisms of action that these large molecules can exert in the human body. Although direct genotoxic mechanisms cannot be excluded, hazardous interactions on biological systems cannot be ruled out, as in the case of natural peptide toxins and their specific interactions with cellular or membrane targets. From a regulatory perspective, only after specific risk identification and characterization should an equally specific safety threshold in relation to potential toxicity be defined.

Investigation of the Influence of Copovidone Properties and Hot-Melt Extrusion Process on Level of Impurities, In Vitro Release, and Stability of an Amorphous Solid Dispersion Product.

Hot-melt extrusion (HME) is a widely used method for creating amorphous solid dispersions (ASDs) of poorly soluble drug substances, where the drug is molecularly dispersed in a solid polymer matrix. This study examines the impact of three different copovidone excipients, their reactive impurity levels, HME barrel temperature, and the distribution of colloidal silicon dioxide (SiO2) on impurity levels, stability, and drug release of ASDs and their tablets. Initial peroxide levels were higher in Kollidon VA 64 (KVA64) and Plasdone S630 (PS630) compared to Plasdone S630 Ultra (PS630U), leading to greater oxidative degradation of the drug in fresh ASD tablets. However, stability testing (50 °C, closed container, 50 °C/30% RH, open conditions) showed lower oxidative degradation impurities in ASD tablets prepared at higher barrel temperatures, likely due to greater peroxide degradation. Plasdone S630 is suitable for ASDs with drugs prone to oxidative degradation, while standard purity grades may benefit drugs susceptible to free radical degradation, as they generate fewer free radicals post-HME. ASD tablets exhibited greater physical stability than milled extrudate samples, likely due to reduced exposure to stability conditions within the tablet matrix. Including SiO2 in the extrudate composition resulted in greater physical stability of the ASD system in the tablet; however, it negatively affected chemical stability, promoting greater oxidative degradation and hydroxylation of the drug substance. No impact of the distribution of SiO2 on drug release was observed. The study also confirmed the congruent release of copovidone, the drug substance, and Tween 80 using flow NMR coupled with in-line UV/vis. This research highlights the critical roles of peroxide levels and SiO2 in influencing the dissolution and physical and chemical stability of ASDs. The findings provide valuable insights for developing stable and effective pharmaceutical formulations, emphasizing the importance of controlling reactive impurities and excipient characteristics in ASD products prepared by using HME.