Reference Standards to Support Quality of Synthetic Peptide Therapeutics

PURPOSE

Peptides are an important class of therapeutics. Their quality is evaluated using a series of analytical tests, many of which depend on well-characterized reference standards to determine identity, purity, and strength.

OBJECTIVE

Discuss approaches to producing peptide reference standards, including vialing, lyophilization, analytical testing and stability studies.

METHODS

Case studies are used to illustrate analytical approaches to characterize reference standards, including methods for value assignment, content uniformity, and identity testing. Methods described include NMR, mass spectrometry, and chromatography techniques for identity testing and HPLC and GC methods for assessing peptide content and impurities.

RESULTS

This report describes the analytical strategy used to establish peptide reference standard and illustrates how results from multiple labs are integrated to assign a value to the final lyophilized vial. A two-step process for value assignment is described, which uses a mass balance approach to assign a quantitative value to a bulk peptide material. The bulk material is then used as a standard to assign a final value to the vialed material. Testing to confirm peptide identity and to ensure consistency of the vialed material is also described. Considerations for addressing variability, identifying outliers, and implementing stability studies are also presented.

CONCLUSION

The methods and case studies described provide a benchmark for best practices in establishing the preparation, analytical testing, handling, and storage of peptide reference standards for the pharmaceutical industry. Some peptide features, such as chiral or isobaric amino acids, may require additional techniques to ensure a full characterization of the peptide reference standard.

Dual Surface Modifications of NiOx/Perovskite Interface for Enhancement of Device Stability

Various phosphonic acid based self-assembled monolayers (SAMs) have been commonly used for interface modifications in inverted perovskite solar cells. This typically results in significant enhancement of the hole extraction and consequent increase in the power conversion efficiency. However, the surface coverage and packing density of SAM molecules can vary, depending on the chosen SAM material and underlying oxide layer. In addition, different SAM molecules have diverse effects on the interfacial energy level alignment and perovskite film growth, resulting in complex relationships between surface modification, efficiency, and lifetime. Here we show that ethanolamine surface modification combined with [2-(9H-carbazol-9-yl)ethyl]phosphonic acid (2PACz) results in significant improvement in device stability compared to devices with 2PACz modification only. The significantly smaller size of ethanolamine enables it to fill any gaps in 2PACz coverage and provide improved interfacial defect passivation, while its different chemical structure enables it to provide complementary effects to 2PACz passivation. Consequently, the perovskite films are more stable under illumination (slower photoinduced segregation), and the devices exhibit significant stability enhancement. Despite similar power conversion efficiencies (PCE) between 2PACz only and combined ethanolamine-2PACz modification (PCE of champion devices ∼21.6-22.0% for rigid and ∼20.2-21.0% for flexible devices), the T₈₀ lifetime under simulated solar illumination in ambient is improved more than 15 times for both rigid and flexible devices.

Non-Alcohol Hand Sanitiser Gels with Mandelic Acid and Essential Oils

Antimicrobial hand gels have become extremely popular in recent years due to the COVID-19 pandemic. Frequent use of hand sanitising gel can lead to dryness and irritation of the skin. This work focuses on the preparation of antimicrobial acrylic acid (Carbomer)-based gels enhanced by non-traditional compounds-mandelic acid and essential oils-as a substitute for irritating ethanol. Physicochemical properties (pH and viscosity), stability and sensory attributes of the prepared gels were investigated. Antimicrobial activity against representative Gram-positive and Gram-negative bacteria and yeasts was determined. The prepared gels with mandelic acid and essential oil (cinnamon, clove, lemon, and thyme) proved to have antimicrobial activity and even better organoleptic properties than commercial ethanol-based antimicrobial gel. Further, results confirmed that the addition of mandelic acid had a desirable effect on gel properties (antimicrobial, consistency, stability). It has been shown that the essential oil/mandelic acid combination can be a dermatologically beneficial hand sanitiser compared to commercial products. Thus, the produced gels can be used as a natural alternative to alcohol-based daily hand hygiene sanitisers.

The Effect of Humidity on the Dissolution Kinetics and Tablet Properties of Immediate-Release Tablet Formulation Containing Lamotrigine

This study aims to find the effects of high (75%) and low (30%) humidity conditions and its correlation with formulation composition on dissolution kinetics of lamotrigine (LMT) from prepared immediate-release tablets during one- and four-week periods. Two types of fillers microcrystalline cellulose (MCC) or anhydrous lactose (LAC), disintegrant sodium starch glycolate (NaSG, 0.5% or 4%), and lubricant magnesium stearate (MgST, 0.25% or 5%) were used. A three-factor two-stage complete factorial design (2³) was used to assess the influence of the composition of the tested formulations. The tablets were produced by direct compression and characterized using a disintegration test, a resistance to crushing test, and dissolution tests (pH 1.2 and pH 6.8). Using Design Expert software, it was concluded that in addition to the effect of fillers on pH 6.8, NaSG has a significant impact after exposure to high and low humidity, as well as its interaction with LAC and MCC. In the dissolution medium pH 1.2, under conditions of high humidity, the content of MgST and NaSG and their interaction show a significant influence. The release rate of LMT was affected by humidity as well as type of excipients and their interactions.

[Preparation and in vitro evaluation of quercetin nanosuspension stabilized by gypenosides]

This study was designed to explore the potential of gypenosides as a novel natural stabilizer for the production of nanosuspensions. The gypenosides-stabilized quercetin nanosuspensions(QUE-NS) were prepared using the high-speed shearing and high-pressure homogenization method with quercetin as a model drug, followed by their in vitro evaluation.Based on the measured mean particle size and polydispersity index(PDI) of QUE-NS,the single factor experiment was conducted to optimize the preparation process parameters.The freeze-drying method was used to transform QUE-NS into freeze-dried powders, whose storage stability and saturation solubility were then studied.Moreover, the effects of pH and ionic strength on the physical stability of the nanosuspension system were examined.According to the results, the optimized process parameters were listed as follows: shear rate 13 000 r·min~(-1),shear time 2 min, homogenization pressure 100 MPa, and homogenization frequency 12 times.The mean particle size of QUE-NS prepared under the optimum process conditions was(461.9±2.4) nm, and the PDI was 0.059±0.016.During the two months of storage at room temperature, the freeze-dried QUE-NS powders remained stable.The saturation solubility of freeze-dried QUE-NS powders was proved higher than those of quercetin and the physical mixture.The results of stability testing demonstrated that QUE-NS stabilized with gypenosides exhibited good stability within the pH range of 6 to 8,while coalescence was prone to occur in the presence of salt.Overall, gypenosides is expected to become a new natural stabilizer for the preparation of nanosuspensions.

Enhancing the Stabilization Potential of Lyophilization for Extracellular Vesicles

Extracellular vesicles (EV) are an emerging technology as immune therapeutics and drug delivery vehicles. However, EVs are usually stored at -80 °C which limits potential clinical applicability. Freeze-drying of EVs striving for long-term stable formulations is therefore studied. The most appropriate formulation parameters are identified in freeze-thawing studies with two different EV types. After a freeze-drying feasibility study, four lyophilized EV formulations are tested for storage stability for up to 6 months. Freeze-thawing studies revealed improved colloidal EV stability in presence of sucrose or potassium phosphate buffer instead of sodium phosphate buffer or phosphate-buffered saline. Less aggregation and/or vesicle fusion occurred at neutral pH compared to slightly acidic or alkaline pH. EVs colloidal stability can be most effectively preserved by addition of low amounts of poloxamer 188. Polyvinyl pyrrolidone failed to preserve EVs upon freeze-drying. Particle size and concentration of EVs are retained over 6 months at 40 °C in lyophilizates containing 10 mm K- or Na-phosphate buffer, 0.02% poloxamer 188, and 5% sucrose. The biological activity of associated beta-glucuronidase is maintained for 1 month, but decreased after 6 months. Here optimized parameters for lyophilization of EVs that contribute to generate long-term stable EV formulations are presented.

Stability of Metronidazole and Its Complexes with Silver(I) Salts under Various Stress Conditions

Metronidazole is a drug widely used in the prevention and treatment of bacterial infections. Due to its possibility of the formation of stable metal complexes, it was decided to broaden its activity spectrum by introducing the silver(I) coordination compounds i.e., [Ag(MTZ)2NO3] and [(Ag(MTZ)2)2]SO4, which have significant antibacterial properties. The paper presents a description of a new qualitative and quantitative analysis of metronidazole in bulk and possible pharmaceutical preparations by thin-layer chromatography with densitometric detection. Optimal separation conditions were selected, and the analytical procedure was validated according to the ICH guidelines. The obtained data indicate that the method is sufficiently sensitive, precise, and accurate. The stability of the metronidazole solutions obtained from tablets, pure metronidazole, and its silver(I) complexes was tested. The research was carried out in various environments, at different temperatures, in H2O2 solution, and during exposure to radiation (UV, sunlight). The greatest degradation was found in the alkaline environment and at higher temperatures. The silver(I) complexes exhibited relatively high stability under analyzed conditions that are higher than standard metronidazole solutions and tablets. The observations were confirmed by the kinetic and thermodynamic analysis. The described studies of new metronidazole silver(I) complexes increase the potential for their application in infections both in humans and animals.

Perspectives on the Phase 0 clinical trial of microdose administration of ABY-029 for fluorescence guided surgery: Stability testing

ABY-029, an anti-epidermal growth factor receptor (EGFR) Affibody molecule labeled with IRDye 800CW, has been used in three Phase 0 microdosing clinical trials for fluorescence guided surgery. In May of 2019, the clinical trials were put on hold because the ABY-029 produced under Good Manufacturing Practices (GMP) for human administration had come to the end of term in which the drug product was known to be stable. Stability testing was halted due to limitations in supply of a suitable reference standard and a required test product being discontinued from commercial sale. In order to complete the remaining patients in the three clinical trials, new stability tests were developed and the GMP batch of ABY-029 drug product tested under the new protocols. The GMP batch of ABY-029 passed all stability tests under the new protocols and the Federal Drug Administration (FDA) has given permission to complete the remaining patients with stability testing of ABY-029 performed for each patient. The tests developed and used to test ABY-029 drug product stability are described here.

Quality control and testing evaluation of pharmaceutical aerosols

Drug delivery to the respiratory tract locally has become an increasingly effective and important therapeutic method for treating a variety of pulmonary disorders, including chronic abstractive disease, asthma, bronchitis, pneumonia, and cystic fibrosis. Increase in prevalence respiratory disorders is a major factor driving the growth of global respiratory inhaler devices market. The effectiveness of pharmaceutical aerosols therapeutic performance is affected by various factors such as type and characteristics of propellants, whose properties are vapor pressure of propellants, viscosity and density flash point and also other factors such as type and characteristics of active ingredients, containers, valves, and actuators, along with percentage of moisture content and mechanism of emitted dose deposition, spray pattern, efficiency of valve crimping, and measurement of particle size aerosols. The purpose of this book chapter is to discuss the in-process and finished product quality control tests for pharmaceutical aerosols based on pharmacopeia standards and specifications.

Stability Study and a 14-Day Oral Dose Toxicity in Rats of Plantain Leaf Extract (Plantago lanceolata L.) Syrup

Plants have been used since antiquity to treat and prevent diseases. Plantain (Plantago lanceolata L.) is traditionally used for the treatment of the common cold and associated symptoms such as cough. This study was designed to evaluate the oral toxicity of plantain leaf extract-containing syrup. In preparation of the toxicological examination and to ensure the quality of the herbal preparation, analytical methods were developed and validated, and stability testing was performed. Physicochemical and microbial quality, thin layer chromatography patterns and high performance liquid chromatography fingerprints complied with the specifications during the entire period of stability testing. The marker substance, acteoside, remained within the stability-defining limits of 90%–110% for quantitative determinations. No hint of toxicity emerged from 14-day repeat dose toxicity testing in rats. The animals were given doses of 3, 6, or 12 mL of syrup per kg body weight by gavage twice daily. All animals showed normal appearance and behavior. Body and organ weights at the end of the study were similar to those in the control group. Overall, P. lanceolata syrup was found to be stable and non-toxic under the test conditions.

A new tool for monoclonal antibody analysis: application of IdeS proteolysis in IgG domain-specific characterization

Monoclonal antibody (mAb) products are extraordinarily heterogeneous due to the presence of a variety of enzymatic and chemical modifications, such as deamidation, isomerization, oxidation, glycosylation, glycation, and terminal cyclization. The modifications in different domains of the antibody molecule can result in different biological consequences. Therefore, characterization and routine monitoring of domain-specific modifications are essential to ensure the quality of the therapeutic antibody products. For this purpose, a rapid and informative methodology was developed to examine the heterogeneity of individual domains in mAb products. A recently discovered endopeptidase, IdeS, cleaves heavy chains below the hinge region, producing F(ab') 2 and Fc fragments. Following reduction of disulfide bonds, three antibody domains (LC, Fd, and Fc/2) can be released for further characterization. Subsequent analyses by liquid chromatography/mass spectrometry, capillary isoelectric focusing, and glycan mapping enable domain-specific profiling of oxidation, charge heterogeneity, and glycoform distribution. When coupled with reversed phase chromatography, the unique chromatographic profile of each molecule offers a simple strategy for an identity test, which is an important formal test for biopharmaceutical quality control purposes. This methodology is demonstrated for a number of IgGs of different subclasses (IgG1, IgG2, IgG4), as well as an Fc fusion protein. The presented technique provides a convenient platform approach for scientific and formal therapeutic mAb product characterization. It can also be applied in regulated drug substance batch release and stability testing of antibody and Fc fusion protein products, in particular for identity and routine monitoring of domain-specific modifications.

Factors affecting motorcycle helmet use: size selection, stability, and position

OBJECTIVES

One of the main requirements of a protective helmet is to provide and maintain appropriate and adequate coverage to the head. A helmet that is poorly fitted or fastened may become displaced during normal use or even ejected during a crash.

METHODS

Observations and measurements of head dimensions, helmet position, adjustment, and stability were made on 216 motorcyclists. Helmet details were recorded. Participants completed a questionnaire on helmet usability and their riding history. Helmet stability was assessed quasistatically.

RESULTS

Differences between the dimensions of ISO headforms and equivalent sized motorcyclists' heads were observed, especially head width. Almost all (94%) of the helmets were labeled to be compliant with AS/NZS 1698 (2006). The majority of riders were satisfied with the comfort, fit, and usability aspects of their helmets. The majority of helmets were deemed to have been worn correctly. Using quasistatic pull tests, it was found that helmet type (open-face or full-face) and the wearing correctness were among factors that affected the loads at which helmets became displaced. The forces required to displace the helmet were low, around 25 N.

CONCLUSIONS

The size of the in-use motorcycle helmets did not correspond well to the predicted size based on head dimensions, although motorcyclists were generally satisfied with comfort and fit. The in vivo stability tests appear to overpredict that helmets will come off in a crash, based on the measured forces, tangential forces measured in the oblique impact tests, and the actual rate of helmet ejection.

Bicycle helmet size, adjustment, and stability

OBJECTIVES

One of the main requirements of a protective bicycle helmet is to provide and maintain adequate coverage to the head. A poorly fitting or fastened helmet may be displaced during normal use or even ejected during a crash. The aims of the current study were to identify factors that influence the size of helmet worn, identify factors that influence helmet position and adjustment, and examine the effects of helmet size worn and adjustment on helmet stability.

METHODS

Recreational and commuter cyclists in Sydney were surveyed to determine how helmet size and/or adjustment affected helmet stability in the real world. Anthropometric characteristics of the head were measured and, to assess helmet stability, a test analogous to the requirements of the Australian bicycle helmet standard was undertaken.

RESULTS

Two hundred sixty-seven cyclists were recruited across all age groups and 91% wore an AS/NZS 2063-compliant helmet. The main ethnic group was Europeans (71%) followed by Asians (18%). The circumferences of the cyclists' heads matched well the circumference of the relevant ISO headform for the chosen helmet size, but the head shapes differed with respect to ISO headforms. Age and gender were associated with wearing an incorrectly sized helmet and helmet adjustment. Older males (>55 years) were most likely to wear an incorrectly sized helmet. Adult males in the 35-54 year age group were most likely to wear a correctly adjusted helmet. Using quasistatic helmet stability tests, it was found that the correctness of adjustment, rather than size, head dimensions, or shape, significantly affected helmet stability in all test directions.

CONCLUSIONS

Bicycle helmets worn by recreational and commuter cyclists are often the wrong size and are often worn and adjusted incorrectly, especially in children and young people. Cyclists need to be encouraged to adjust their helmets correctly. Current headforms used in standards testing may not be representative of cyclists' head shapes. This may create challenges to helmet suppliers if on one hand they optimize the helmet to meet tests on ISO-related headforms while on the other seeking to offer greater range of sizes.

Real-time stability testing of air-dried primers and fluorogenic hydrolysis probes stabilized by trehalose and xanthan

A method for conserving primers and differently labeled fluorogenic hydrolysis (i.e., TaqMan) probes at ambient conditions is presented. Primers and hydrolysis probes with four different fluorophore-quencher combinations (6- FAM-BHQ1, HEX-BHQ1, ROX-BHQ650, and Cy5-BHQ2) were mixed with trehalose and xanthan at final concentrations of 56 mM and 2.78 mM, respectively. Mixtures were air-dried at 23°C for 30 min on strips composed of cyclo olefin polymer (COP), a material widely used in the manufacturing of in vitro diagnostic (IVD) test carriers. After one year of storage, the functionality of the primers and fluorophore-quencher combinations was validated by real-time polymerase chain reaction (real-time PCR), confirming their stability when stored in the presence of stabilizers, with the best results achieved using trehalose. This approach could be of great benefit for manufacturing IVD systems, for example, for genotyping applications based on multiplexing using different fluorescent dyes.