The potential clinical relevance of visible particles in parenteral drugs

Comparing visual inspection methods for parenteral products in hospital pharmacy: between reliability, cost, and operator formation considerations

INTRODUCTION

The COVID-19 pandemic has led to unforeseen and novel manifestations, as illustrated by the management of drug shortages through the development of hospital production of sterile pharmaceutical preparations (P2S). Visual inspection of P2S is a release control whose methods are described in monographs of the European Pharmacopoeia (2.9.20) and the United States Pharmacopeia (1790). However, these non-automated visual methods require training and proficiency testing of personnel. The main objective of this work was to compare the reliability and speed of analysis of two visual methods and an automated method for detecting visible particles by image analysis in P2S. Furthermore, these methods were used to evaluate sources of particulate contamination during pre-production processes (washing, disinfection, depyrogenation) and production (filling, capping).

MATERIALS AND METHODS

Three pharmacy technicians examined 41 clear glass vials of type I, 10 and/or 50 mL through manual visual inspection (MVI), semi-automated (SAVI), and automated (AVI) inspection. The vials were distributed as follows: (i) 16 vials of water for injection containing either glass particles (224 µm or 600 µm), stopper fragments, or textile fibres; (ii) five sterile injectable specialties; (iii) 20 vials of water for injection prepared under different pre-production conditions.

RESULTS AND DISCUSSION

MVI and SAVI detected 100% of visible particles compared with 28% for AVI, which showed a deficiency in detecting textile fibres. All three methods correctly analysed P2S that did not contain visible particles. The three methods detected particles in vials maintained under International Organization for Standardization (ISO) 9 pre-production conditions. However, detections by (i) MVI and SAVI, and by (ii) AVI of particles contained in vials maintained under ISO 8 pre-production conditions were deemed satisfactory and unsatisfactory, respectively.

CONCLUSION

The importance of visual inspection of P2S requires rapid, sensitive, and reliable detection methods. In this context, MVI and SAVI have proven to be more effective than AVI for a more competitive financial, training, and implementation investment.

Stability of Protein Pharmaceuticals: Recent Advances

There have been significant advances in the formulation and stabilization of proteins in the liquid state over the past years since our previous review. Our mechanistic understanding of protein-excipient interactions has increased, allowing one to develop formulations in a more rational fashion. The field has moved towards more complex and challenging formulations, such as high concentration formulations to allow for subcutaneous administration and co-formulation. While much of the published work has focused on mAbs, the principles appear to apply to any therapeutic protein, although mAbs clearly have some distinctive features. In this review, we first discuss chemical degradation reactions. This is followed by a section on physical instability issues. Then, more specific topics are addressed: instability induced by interactions with interfaces, predictive methods for physical stability and interplay between chemical and physical instability. The final parts are devoted to discussions how all the above impacts (co-)formulation strategies, in particular for high protein concentration solutions.'

Visible particles in parenteral drug products: A review of current safety assessment practice

Parenteral drug products (PDPs) are administered extensively to treat various diseases. Product quality plays a critical role in ensuring patient safety and product efficacy. One important quality challenge is the contamination of particles in PDPs. Particle presence in PDPs represents potential safety risk to patients. Differential guidance and practice have been in place for visible (VPs) and subvisible particles (SVPs) in PDPs. For SVPs, the amount limits have been harmonized in multiple Pharmacopeias. The pharmaceutical industry follows the guided limits for regulatory and quality compliance. However, for VPs, no such acceptable limit has been set. This results in not only quality but also safety challenges for manufacturers and drug developers in managing and evaluating VPs. It is important to understand the potential safety risk of VPs so these can be weighed against the benefit of the PDPs. To evaluate their potential risk(s), it is necessary to understand their nature, origin, frequency of their occurrence, safety risk, the risk mitigation measures, and the method to evaluate their safety. The current paper reviews the critical literature on these aspects and provides insight into considerations when performing safety assessment and managing the risk(s) for VPs in PDPs.

Evaluating Clinical Safety and Analytical Impact of Subvisible Silicone Oil Particles in Biopharmaceutical Products

Silicone oil is a commonly used lubricant in pre-filled syringes (PFSs) and can migrate over time into solution in the form of silicone oil particles (SiOPs). The presence of these SiOPs can result in elevated subvisible particle counts in PFS drug products compared to other drug presentations such as vials or cartridges. Their presence in products presents analytical challenges as they complicate quantitation and characterization of other types of subvisible particles in solution. Previous studies have suggested that they can potentially act as adjuvant resulting in potential safety risks for patients. In this paper we present several analytical case studies describing the impact of the presence of SiOPs in biotherapeutics on the analysis of the drug as well as clinical case studies examining the effect of SiOPs on patient safety. The analytical case studies demonstrate that orthogonal techniques, especially flow imaging, can help differentiate SiOPs from other types of particulate matter. The clinical case studies showed no difference in the observed patient safety profile across multiple drugs, patient populations, and routes of administration, indicating that the presence of SiOPs does not impact patient safety.

An Interlaboratory Study to Identify Potential Visible Protein-Like Particle Standards

Visible protein-like particle standards may improve visual inspection and/or appearance testing practices used in the biotechnology industry. They may improve assay performance resulting in better alignment and more standardized training among different companies. The National Institute of Standards and Technology (NIST) has conducted an interlaboratory study to test whether the standards under development mimic typical proteinaceous particles found in biotherapeutics and if they can be implemented during the visual inspection process. Fourteen organizations from industry and government have participated. A total of 20 labs from these 14 organizations participated with analysts from 6 formulation, 7 analytical, 4 quality control, and 3 manufacturing labs. The circulated samples consisted of abraded ethylene tetrafluoroethylene (ETFE) particles or photolithographic particles. The results consist of qualitative ratings, which varied substantially among organizations and within labs. Polydisperse ETFE particle suspensions, containing particles enriched in greater than 150 µm in size, were rated more favorably than the photolithographic particles by formulation and analytical scientists. The largest monodisperse photolithographic particles (approximately 300 µm in size) were favored equally compared to ETFE by all scientists. Solution modifications to decrease the settling rate or to alter optical properties of the ETFE solutions yielded lower ratings by the analysts. Both particle types received mixed ratings for their usability and for their application for visual inspection and for training purposes. Industry feedback will assist NIST in developing reference material(s) for visible protein-like particles.

Graphical Abstract

Formulation mitigations for particle formation induced by enzymatic hydrolysis of polysorbate 20 in protein-based drug products: insights from a full-factorial longitudinal study

Hydrolytic degradation of the polysorbate 20 (PS20) surfactant in protein-based liquid formulations releases free fatty acids (FFAs), which can accumulate to form particles in drug products during real-time (long-term) storage. To identify formulation conditions that mitigate the risk of particle formation, we conducted a longitudinal study using purified recombinant monoclonal antibody (mAb) formulated in 24 conditions. In this real-time stability study at 5 °C, three key formulation parameters—mAb concentration, initial PS20 concentration, and pH—were varied across representative ranges in a full-factorial design. A longitudinal regression analysis was used to evaluate the effects of these parameters and their interactions on PS20 degradation (via measurements of PS20, FFAs, and PS20 ester distribution) and on particle formation (via visible particle observations and subvisible particle counts). The time-dependent onset of visible particles trended with the rise in subvisible particle counts and FFA levels and fall in PS20 concentration. In the ranges studied here, lower mAb concentration and higher initial PS20 concentration delayed the onset of particles, whereas pH had a negligible effect. These observations were consistent with the general trends predicted by our previously published FFA solubility model. Taken together, these findings highlight the complex relationships between formulation parameters, PS20 degradation, and particle formation.

Particles in Biopharmaceutical Formulations, Part 2: An Update on Analytical Techniques and Applications for Therapeutic Proteins, Viruses, Vaccines and Cells

Particles in biopharmaceutical formulations remain a hot topic in drug product development. With new product classes emerging it is crucial to discriminate particulate active pharmaceutical ingredients from particulate impurities. Technical improvements, new analytical developments and emerging tools (e.g., machine learning tools) increase the amount of information generated for particles. For a proper interpretation and judgment of the generated data a thorough understanding of the measurement principle, suitable application fields and potential limitations and pitfalls is required. Our review provides a comprehensive overview of novel particle analysis techniques emerging in the last decade for particulate impurities in therapeutic protein formulations (protein-related, excipient-related and primary packaging material-related), as well as particulate biopharmaceutical formulations (virus particles, virus-like particles, lipid nanoparticles and cell-based medicinal products). In addition, we review the literature on applications, describe specific analytical approaches and illustrate advantages and drawbacks of currently available techniques for particulate biopharmaceutical formulations.

Metal-Induced Fatty Acid Particle Formation Resulting from Hydrolytic Polysorbate Degradation

The occurrence of visible particles over the shelf-life of biopharmaceuticals is considered a potential safety risk for parenteral administration. In many cases, particle formation resulted from the accumulation of fatty acids released by the enzymatic hydrolysis of the polysorbate surfactant by co-purified host cell proteins. However, particle formation can occur before the accumulated fatty acids exceed their expected solubility limit. This early onset of particle formation is driven by nucleation phenomena e.g. the presence of metal cations that promote the formation and growth of fatty acid particles. To further characterize and understand this phenomenon, we assessed the potential of different metal cations to induce fatty acid particle formation using a dynamic light scattering assay. We demonstrated that the presence of trace amounts of multivalent cations, in particular trivalent cations such as aluminum and iron, may act as nucleation seed in the process of particle formation. Finally, we developed a mitigation strategy for metal-induced fatty acid particles that deploys a chelator to reduce the risk of particle formation in biopharmaceutical formulations.

Pharmaceutical Excipients Enhance Iron-Dependent Photo-Degradation in Pharmaceutical Buffers by near UV and Visible Light: Tyrosine Modification by Reactions of the Antioxidant Methionine in Citrate Buffer

PURPOSE

To evaluate the effect of excipients, including sugars and amino acids, on photo-degradation reactions in pharmaceutical buffers induced by near UV and visible light.

METHODS

Solutions of citrate or acetate buffers, containing 1 or 50 μM Fe³⁺, the model peptides methionine enkephalin (MEn), leucine enkephalin (LEn) or proctolin peptide (ProP), in the presence of commonly used amino acids or sugars, were photo-irradiated with near UV or visible light. The oxidation products were analyzed by reverse-phase HPLC and HPLC-MS/MS.

RESULTS

The sugars mannitol, sucrose and trehalose, and the amino acids Arg, Lys, and His significantly promote the oxidation of peptide Met to peptide Met sulfoxide. These excipients do not increase the yields of hydrogen peroxide, suggesting that other oxidants such as peroxyl radicals are responsible for the oxidation of peptide Met. The addition of free Met reduces the oxidation of peptide Met, but, in citrate buffer, causes the addition of Met oxidation products to Tyr residues of the target peptides.

CONCLUSIONS

Commonly used excipients enhance the light-induced oxidation of amino acids in model peptides.

Physical compatibility of alprostadil with selected drugs commonly used in the neonatal intensive care units

This study aimed to determine the physical compatibility of alprostadil with 17 continuous infusion drugs commonly administered in neonatal intensive care units. Test samples were prepared in a laminar airflow hood. Alprostadil 20 mcg/ml was mixed with each drug in a 1:1 ratio, in two orders of mixing. Physical stability of the admixtures was assessed by visual examination and by measuring turbidity. Visual examination was conducted by two observers by two methods: visual examination against a black and white background under normal fluorescent light and using a high-intensity monodirectional light. pH was measured as chemical stability predictor. Evaluations were performed immediately and 4 h after mixing. An additional visual control was performed at 24 h. Visual examination was positive or doubtful for the four drug combinations not considered compatible. Turbidity values were under 0.5 NTU throughout the study in all samples. No modifications of one pH unit or more was detected in any drug pair over time.Conclusion: Alprostadil was considered physical compatible with 13 drugs (adrenalin, amiodarone, calcium gluconate, dobutamine, dopamine, fentanyl, flecainide, furosemide, heparin, ketamine, midazolam, milrinone and morphine). Incompatibility could not be ruled out for 3 drugs (cisatracurium, dexmedetomidine and noradrenalin), and insulin was considered incompatible with alprostadil. What is Known: • Y-site administration is common in neonatal intensive care units, and volume of diluents and rate of infusions in newborns were lower than in adults which might result in high concentrations and prolonged contact time at Y-site administration. • Available data about compatibility of alprostadil with other drugs was scarce. What is New: • Alprostadil was compatible with 13 drugs commonly used in neonatal intensive care units. • Insulin was considered incompatible with alprostadil, and incompatibility cannot be ruled out for cisatracurium, dexmedetomidine and noradrenalin with alprostadil.

Lyophilization Serves as an Effective Strategy for Drug Development of the α9α10 Nicotinic Acetylcholine Receptor Antagonist α-Conotoxin GeXIVA[1,2]

α-Conotoxin GeXIVA[1,2] is a highly potent and selective antagonist of the α9α10 nicotinic acetylcholine receptor (nAChR) subtype. It has the advantages of strong efficacy, no tolerance, and no effect on motor function, which has been expected help patients with neuropathic pain. However, drug development for clinical use is severely limited owing to its instability. Lyophilization is applied as the most preferred method to solve this problem. The prepared lyophilized powder is characterized by differential scanning calorimetry (DSC), powder X-ray diffractometry (PXRD), and Fourier transform infrared spectroscopy (FTIR). Molecular simulation is also used to explore the internal distribution and forces formed in the system. The analgesic effect on paclitaxel-induced neuropathic pain following single and 14-day repeated administrations are evaluated by the von Frey test and the tail-flick test. Trehalose combined with mannitol in a ratio of 1:1 is employed as the excipients in the determined formulation, where trehalose acts as the stabilizer and mannitol acts as the bulking agent, according to the results of DSC, PXRD, and FTIR. Both GeXIVA[1,2] (API) and GeXIVA[1,2] lyophilized powder (formulation) could produce stable analgesic effect. These results indicated that GeXIVA[1,2] lyophilized powder could improve the stability and provide an effective strategy to push it into clinical use as a new analgesic drug.

Evaluation of Particle Techniques for the Characterization of Subvisible Particles From Elastomeric Closure Components

Evaluating a particle profile for parenteral drug products is a well-known challenge due to inevitable variability of results with limited accuracy to actual particle levels present in the product, especially in the subvisible particulate (SbVP) range. It is important to understand the appropriate SbVP counting/characterization technology, methodology capability, and the particle source (intrinsic or extrinsic). Elastomeric closures are prevalent in many types of drug product container closure systems and are a known source of particle contribution. These components need to be considered when establishing a drug product particle profile. In this work, we describe available particle extraction methodology and its applicability in the analysis of elastomeric closure components using multiple detection technologies. Optimum sample preparation and analytical techniques were established to evaluate submicron particle and SbVP loads from elastomeric closure components. In addition, the impact of stopper siliconization and polysorbate 80 interaction on the degree of SbVPs in the final drug product was assessed.

Variance Between Different Light Obscuration and Flow Imaging Microscopy Instruments and the Impact of Instrument Calibration

Subvisible particles (SVPs) are an obligatory critical quality attribute of the product, and yet, they are found in all biopharmaceutical products intended for infusion or injection. Light obscuration (LO) is the primary pharmacopeial method used to quantify SVPs. However, the method may not be equally sensitive toward all particles that can possibly occur. Calibration of LO instruments is usually performed using polystyrene beads suspended in water. In this study, the dependence of the sizing accuracy of LO analysis was evaluated by using a calibration suspension of lower refractive index beads made of silica suspended in sucrose solution. It was demonstrated that the sizing accuracy was strongly dependent on the reference material's properties used for calibration. It was also demonstrated that flow imaging microscopy suffered from the same artifact, albeit to a smaller extent. We further tested different LO sensors and instruments. Interestingly, our results show that the sizing accuracy varied from instrument to instrument, strongly depending on the properties of the sensor. To summarize, sizing and counting accuracies were dependent on the material used for calibration and its optical properties as well as the calibration curve, the sensor, and the instrument supplier. Closer match of optical properties between calibration system and test system seems to improve the sensitivity of the measurement. The results of this study raise the following major practical implications: (1) LO and flow imaging microscopy are not truly orthogonal analytical methods, (2) while matching optimal properties of material used for calibration and test items increased sensitivity, this is of poor practical applicability given that analytes contain multiple particles, and (3) setting product-specific limits for SVPs require special considerations with regard to the data sets used.

Expanding Bedside Filtration-A Powerful Tool to Protect Patients From Protein Aggregates

Protein immunogenicity is intensively researched by academics, biopharmaceutical companies, and authorities as it can compromise the safety and efficacy of a biopharmaceutical drug. So far, the exact protein aggregate properties inducing immune responses are not known. Possible protein-related factors could be size, chemical modifications, or higher order structures. It is impossible to achieve an absolute absence of protein aggregates even for very stable formulations. The application of "bedside filtration," meaning filtration during the preparation or administration of the drug product immediately before injection, has the potential to increase the safety of every drug container and could prevent the undesired injection of particulate matter into the patient. In this study, the high efficiency of filtration for reducing the amount of protein particles was demonstrated with more than 19 stressed and nonstressed biopharmaceutical products which covered a broad concentration and molecular weight range. Furthermore, critical aspects regarding the usage of filters such as particle shedding from filters, protein loss as a result of protein adsorption, or the hold-up volume of the filters were assessed. Although differences between the filters were observed, no negative impact by the investigated filters could be found. A broader application of bedside filtration is therefore proposed.

A Newly Identified Impurity in Polysorbate 80, the Long-Chain Ketone 12-Tricosanone, Forms Visible Particles in a Biopharmaceutical Drug Product

Visible particles linked to polysorbates (PSs) used in biopharmaceutical drug products (DPs) have been observed repeatedly in recent years as an industry-wide issue, with PS degradation and insoluble degradation products, especially fatty acids and fatty acid esters, being suspected as root cause. We have shown that the visible particles observed in a monoclonal antibody DP solution in vials after 18 months of long-term storage at 5 ± 3°C were neither linked to reduction in PS (PS80) concentration nor to any known PS degradation product, but consist of 12-tricosanone, an impurity present in the raw material PS80, not a degradation product. The occurrence of visible 12-tricosanone particles in DP correlated with the usage of specific PS80 raw material lots, where 12-tricosanone was found as impurity at elevated levels. The quantities detected in these PS80 lots directly translate into the amount found in the respective monoclonal antibody DP batches. This is the first time that a clear correlation between the occurrence of the impurity 12-tricosanone in PS80 and the occurrence of visible particles in DP batches is reported. The observation and techniques described enable the control of this ketone in PS raw materials, providing means to prevent respective visible particle formation in DP.

Rubber Coring of Injectable Medication Vial Stoppers: An Evaluation of Causal Factors

Purpose:

Coring of a medication vial’s rubber stopper has been reported as a major cause of visible particle presence in injectable preparations. In this study, we investigated and quantified visible particle formation caused by coring associated with four potential causal factors.

Methods:

The factors studied were: nature of the rubber stopper; rubber stopper thickness, type of metal needle bevel used to pierce the stopper, and puncture technique. For each one of 16 different situations, 40 medication vial rubber stoppers were punctured, and the contents filtered. The filters were then examined under optical microscopy and particles present counted and measured.

Results:

The incidence of particle formation ranged from 0 % to 75 %, depending on the situation. Particle length was on average of 0.98±0.39 mm. The situation that gave the most particles (75 %; 30/40) was obtained when using a short bevelled needle, a 4 mm thick chlorobutyl vial stopper and with a puncture angle of 90°. Whilst a puncture technique reduced particle formation by more than 50 % for the most at risk situation, but without eliminating particle formation (residual formation of 22.5 %; 11/40), the use of a blunt bevelled needle totally eliminated the incidence of visible particle creation. The thickness of the rubber and the nature of the elastomer seemed to be linked to coring incidence, but in lesser proportions.

Conclusion:

Puncturing the stoppers using a technique with a 45° puncture angle reduced particle formation, but only the use of a blunt metal needle totally eliminated it.

Particulate Matter in Injectable Drugs: Evaluation of Risks to Patients

One of the fundamental principles guiding the pharmaceutical quality of parenteral products is to prevent injecting contaminants from microbiological, chemical or physical sources. It is just as difficult to ensure the absence of chemical and particulate contaminants in injectable products as it is to weigh up the microbiological risk. The problem of particulate matter is mainly related to the preparing and administrating of injectable drugs rather than through the contamination of marketed products. Particulate contamination also arises

Utilizing dynamic light scattering as a process analytical technology for protein folding and aggregation monitoring in vaccine manufacturing

Protein aggregation is a common challenge in the manufacturing of biological products. It is possible to minimize the extent of aggregation through timely measurement and in-depth characterization of aggregation. In this study, we demonstrated the use of dynamic light scattering (DLS) to monitor inclusion body (IB) solubilization, protein refolding, and aggregation near the production line of a recombinant protein-based vaccine candidate. Our results were in good agreement with those measured by size-exclusion chromatography. DLS was also used to characterize the mechanism of aggregation. As DLS is a quick, nonperturbing technology, it can potentially be used as an at-line process analytical technology to ensure complete IB solubilization and aggregate-free refolding.

Impact of preformulation on drug development

INTRODUCTION

Preformulation assists scientists in screening lead candidates based on their physicochemical and biopharmaceutical properties. This data is useful for selection of new chemical entities (NCEs) for preclinical efficacy/toxicity studies which is a major section under investigational new drug application. A strong collaboration between discovery and formulation group is essential for selecting right NCEs in order to reduce attrition rate in the late stage development.

AREAS COVERED

This article describes the significance of preformulation research in drug discovery and development. Various crucial preformulation parameters with case studies have been discussed.

EXPERT OPINION

Physicochemical and biopharmaceutical characterization of NCEs is a decisive parameter during product development. Early prediction of these properties helps in selecting suitable physical form (salt, polymorph, etc.) of the candidate. Based on pharmacokinetic and efficacy/toxicity studies, suitable formulation for Phase I clinical studies can be developed. Overall these activities contribute in streamlining efficacy/toxicology evaluation, allowing pharmacologically effective and developable molecules to reach the clinic and eventually to the market. In this review, the magnitude of understanding preformulation properties of NCEs and their utility in product development has been elaborated with case studies.