Performed Stability Studies Research Articles

Validation of analytical methods for the production of expanded γδ T lymphocytes useful for therapeutic purposes

The use of γδ T lymphocytes as advanced therapeutic medicinal product has attracted much interest in the last years. Indeed, such cells are an ideal tool for the reconstitution of the immune system in patients receiving hematopoietic stem cell transplantation, due to their MHC-independent anti-tumor and anti-viral activities. We have here setup a protocol for the production of pure and functional γδ T lymphocytes, expanded from healthy donors’ mononuclear cells, and validated the analytical methods to identify them and to analyze their potency. Next, we performed stability studies to ensure that the cell product (γδ T cells) can be used after freezing and thawing. Notably, such protocol can be promptly translated to GMP-facility, since it has been designed using only clinical grade reagents.

Enhanced Lithium Ion Diffusivity of Nanosized Li1.2Mn0.8O2 Cathode Material Via Na and Ti Co-Doping

Ionic doping is amongst the most effective modification methods capable of altering the local atomic environment, which in turn governs the redox reactions and electrochemical performance of Li-rich cathode materials. It has been demonstrated to improve bulk structural stability and suppress oxygen loss to some extent. Independently doping with Na and Ti has sparked interest in them however, very little is understood about their combined impact in a quest to address the structural complexities encountered during the operation of Li-rich cathodes. Herein, molecular dynamics simulations were carried out on both the bulk and nanospherical structures of Li1.2Mn0.8O2, Li1.2Mn0.72Ti0.08O2, and Li1.15Na0.05Mn0.72Ti0.08O2 whereNa+ doping in the Li-site and Ti in the Mn site. The temperature variations were between 300K and 2000 K. The findings of this study depict that bulk structures have diffusion coefficients that are orders of magnitude less than those of nanospherical structures. This strongly supports the unique capabilities of nanoparticles in reducing the Li-ion diffusion distance and increasing the contact area between the electrode and the electrolyte. In terms of variation in doped systems, it was observed that singly doping the layered structure with titanium slightly increases ionic diffusion in the Li-Rich structure whereas, co-doping the same structure yields even higher diffusion coefficients. These are possible results of enhanced interlayer spacing as Na generally has a larger ionic radius than Li. Furthermore, the co-doping may have contributed to structural stability wherein cationic mixing influenced by Mn migration in pure Li1.2Mn0.8O2 is largely reduced [1]. This places the two dopants at the pinnacle of capacity enhancement for the Li-rich electrode and sparks significant interest in further performance and structural stability studies.

From an in vivo to an in vitro relative potency (IVRP) assay to fully characterize a multicomponent O-antigen based vaccine against Shigella

Outer membrane vesicles (OMV) represent an innovative platform for the design of polysaccharide based vaccines. Generalized Modules for Membrane Antigens (GMMA), OMV released from engineered Gram-negative bacteria, have been proposed for the delivery of the O-Antigen, key target for protective immunity against several pathogens including Shigella. altSonflex1-2-3 is a GMMA based vaccine, including S. sonnei and S. flexneri 1b, 2a and 3a O-Antigens, with the aim to elicit broad protection against the most prevalent Shigella serotypes, especially affecting children in low-middle income countries.Here we developed an In Vitro Relative Potency assay, based on recognition of O-Antigen by functional monoclonal antibodies selected to bind the key epitopes of the different O-Antigen active ingredients, directly applied to our Alhydrogel-formulated vaccine. Heat-stressed altSonflex1-2-3 formulations were generated and extensively characterized. The impact of detected biochemical changes in in vivo and in vitro potency assays was assessed.The overall results showed how the in vitro assay can replace the use of animals, overcoming the inherently high variability of in vivo potency studies. The entire panel of physico-chemical methods developed will contribute to detect suboptimal batches and will be valuable to perform stability studies. The work on Shigella vaccine candidate can be easily extended to other O-Antigen based vaccines.

Probing voltage-dependent stability of nucleosomes using glass nanopores.

The packaging of DNA in the form of chromatin helps the cell to compact and regulate its genetic material. It is known that the nucleosomes exist in various structural and positional combinations that leads to chromatin assuming locally folded structures. This allows for its efficient packaging and also helps in the gene regulation. In this work, using resistive pulse technique with our glass nanopores, we have investigated the voltage dependent stability of mono-nucleosomes as well as the 12-mer nucleosome arrays. In experiments with our in vitro assembled mononucleosomes, we show that the octasomal nucleosomes, comprising of octameric histone complexes on DNA, systematically breakdown into its partial structures, which we reason to be hexasomes and tetrasomes, in a voltage dependent manner. We attribute these structural changes to the opposing electrical forces experienced by the positively charged histone protein complex and the negatively charged DNA. We next investigate the stability of 12-mer nucleosome arrays and find discrete multi-level events corresponding to discrete structures on the array molecules. A detailed analysis of these discrete levels revealed that these structures correspond to single, multiple as well as partial nucleosomes on the array molecule. We further show that these structures disassemble in a voltage dependent manner. Our work demonstrates, for the first time, application of the glass nanopore platform to perform stability studies on nucleosome-DNA complexes, both individually as well as on nucleosomal arrays. This opens up future studies to evaluate force dependent structural transitions in the context of epigenetic control of chromatin structure.

Stability of Thyroid Function Test Analytes Whose Serum Levels Are Determined by Immunoassay

We have performed stability studies on thyroid function tests, i.e., T4, T3, free T4, free T3 and thyroid stimulating hormone (TSH), over a five-day period on the sera of ten patients. We find that the levels for each analyte were stable; the mean coefficients of variation (CV) ranged from 3.2 % for TSH to 8.7% for T4. ANOVA statistical analysis of group means for each analyte over the five-day period indicated that there was no statistically significant difference in these means, confirming the reproducibility of values. On the other hand, the CVs are significantly larger than those found in our prior stability studies for other critical analytes such as electrolytes (sodium, potassium, chloride, calcium). In addition, significant variations in values over the five-day period occurred for T4 which showed the largest variations in values of the five analytes studied. In one patient, the values ranged from a low of <10 ug/dL to over 14 ug/dL over the five-day period. A two-tailed t test comparing the mean CV for TSH with the mean CVs of the other four analytes showed that the mean CV for TSH was statistically significantly lower than that for the other four analytes indicating that the assay for TSH yield the most precise results. These results parallel those obtained in our prior electrolyte study that showed very low CVs for sodium, potassium and chloride and a significantly higher CV for calcium. Since approximately half of total serum calcium is bound to albumin and since very high percentages of T4 and T3 (≥99%) are bound to thyroid binding globulin and albumin, protein binding of these analytes may introduce a possible source of assay imprecision.

Stereoselective Synthesis and Biological Profile of All Stereoisomers of Lactam Analogues of Strigolactones GR24 and GR18

AbstractStrigolactones (SLs) are signaling molecules involved in plant development and governing interactions with soil microorganisms in the rhizosphere as well as the germination of parasitic weeds. Developing their use in Crop Protection is a promising approach to a sustainable agriculture by mitigating biotic and abiotic stresses. Recently, a new class of lactam analogues of SL has emerged, namely strigolactams, displaying outstanding potency to induce the germination of parasitic weed O. cumana as well as enhanced chemical and soil stability. Herein, we describe the stereoselective synthesis of GR24 and GR18 lactams harnessing the chemistry of chiral keteniminium (KI) salts, in particular the unprecedented reactivity of chloro‐substituted KI, supported by DFT calculations. We disclose subsequently the biological activity on corn of the 32 stereopure strigolactams prepared, highlighting the crucial influence of stereochemistry and lactam substitution, rationalized by docking analyses. Finally, we performed stability studies in soil, which reveal that stereoisomers display very different half‐lives, reflecting the significant impact of stereochemistry on degradation kinetics.

A Machine Learning-Based Method for Identifying Critical Distance Relays for Transient Stability Studies

Protective relays play a crucial role in defining the dynamic responses of power systems during and after faults. Therefore, modeling protective relays in stability studies is crucial for enhancing the accuracy of these studies. Modeling all the relays in a bulk power system is a challenging task due to the limitations of stability software and the difficulties of keeping track of the changes in the setting information of these relays. Distance relays are one of the most important protective relays that are not properly modeled in current practices of stability studies. Hence, using the Random Forest algorithm, a fast machine learning-based method is developed in this paper that identifies the distance relays required to be modeled in stability studies of a contingency, referred to as critical distance relays (CDRs). GE positive sequence load flow analysis (PSLF) software is used to perform stability studies. The method is tested using 2018 summer peak load data of Western Electricity Coordinating Council (WECC) for various system conditions. The results illustrate the great performance of the method in identifying the CDRs. They also show that to conduct accurate stability studies, only modeling the CDRs suffices, and there is no need for modeling all the distance relays.

A Meticulous Appraisal of Vyaghri Haritaki Avaleha – An Ayurvedic Medicament WSR to Stability Study

Stability study of the Ayurvedic formulations plays a significant role to provide actual shelf life of the medicament. Hence, it is necessary to perform stability studies of Ayurvedic compound formulations. The stability study was planned to observe whether any physical, chemical, and microbiological change takes place in Vyaghri Haritaki samples by keeping them at three different temperatures (47°C, 37°C, and 25–30°C) for 3 months. The samples kept for accelerated stability study were analyzed after 3 months and the details have been presented in this section.

Performance Parameters and Stability Studies on FEL-III Beamline of Shanghai High Repetition Rate XFEL and Extreme Light Facility

Performance Parameters and Stability Studies on FEL-III Beamline of Shanghai High Repetition Rate XFEL and Extreme Light Facility

Application of chemometrics using direct spectroscopic methods as a QC tool in pharmaceutical industry and their validation.

This present review described the application of chemometrics using direct spectroscopic methods at the quality control (QC) laboratory of Pharmaceutical Industries. Using chemometrics methods, all QC assessments during the fabrication processes of the drug preparations can be well performed. Chemometrics methods have some advantages compared to the conventional methods, i.e., non-destructive, can be performed directly to intake samples without any extractions, unnecessary performing stability studies, and cost-effective. To achieve reliable results of analyses, all methods must be validated first prior to routine applications. According to the current Pharmacopeia, the validation parameters are specificity/selectivity, accuracy, repeatability, intermediate precision, range, detection limit, quantification limit and robustness. These validation data must meet the acceptance criteria, that have been described by the analytical target profile (ATP) of the drug preparations.

Design, Characterization, Analytical HPLC Method Validation, and Stability Studies of Racecadotril Capsules

This study aims to develop, characterize and validate analytical method and perform stability studies of Racecadotril capsules to treat acute diarrhea. Six formulations of Racecadotril 100mg Capsules were prepared with different excipients by varying their concentrations. The HPLC method was validated on analytical parameters recommended by ICH Q2R guidelines, including specificity, accuracy and recovery, precision, quantitation limit, detection limit, range, linearity, and robustness. Forced degradation studies were performed as per the Stability Indicating Method under various stress conditions. Accelerated stability studies were performed on three stability batches of best fit formulation of Racecadotril 100mg Capsules as per ICH guidelines. Among the six formulations of Racecadotril 100mg Capsule, F6 was the best fit with a comparatively good dissolution profile with 76.9% release in 60 minutes. The HPLC system was suitable as % R.S.D. was 0.619147%, within the acceptance criteria. Furthermore, parameters including specificity, accuracy and recovery, precision, quantitation limit, detection limit, range, linearity, and robustness lie within the acceptance criteria. The percent degradation of Racecadotril after photolytic (sunlight for 6 hr.), oxidative (3% H2O2), acidic (0.1N HCl) and necessary (0.1N NaOH) stress was found to be 6.5%, 5.8%, 11.4%, and 28.4%, respectively. The product remains unchanged after thermal stress. HPLC method was successfully validated for Racecadotril 100mg Capsule as per ICH Q2R guidelines.

UHPLC-DAD Method Development and Validation: Degradation Kinetic, Stress Studies of Farnesol and Characterization of Degradation Products Using LC-QTOF-ESI-MS with in silico Pharmacokinetics and Toxicity Predictions.

Farnesol (FAR) is a sesquiterpene molecule with high lipophilicity that has antibacterial and other pharmacological properties along with broad nutritional values with high commercial values. Although having potential, FAR stability behavior and degradation kinetics are not available in the literature. Hence, it is very essential to develop a simple, rapid, accurate, precise, robust, cheap UHPLC-DAD method for FAR. It was also proposed to study mechanistic insights into FAR under different degradation conditions. Therefore, we hypothesized to do systematic stability studies along with degradation kinetic and accelerated stability studies. The developed method was validated. FAR was studied for stress studies, degradation kinetics and ADMET prediction of degradants. Degradation products were characterized using LC-QTOF-ESI-MS. Developed method consists of an isocratic mobile phase with a wavelength of 215nm. The percent recoveries for FAR were observed within the acceptance limit of 98-102%. The eight major degradation products were formed during stress studies. FAR follows first-order degradation kinetics. FAR and all degradants were found to have more than 75% good human oral absorption, and are non-toxic. FAR UHPLC-DAD method was developed, validated and performed stability studies to know the possible degradation pattern along with degradation kinetic studies.

Long-term stability predictions of therapeutic monoclonal antibodies in solution using Arrhenius-based kinetics

Long-term stability of monoclonal antibodies to be used as biologics is a key aspect in their development. Therefore, its possible early prediction from accelerated stability studies is of major interest, despite currently being regarded as not sufficiently robust. In this work, using a combination of accelerated stability studies (up to 6 months) and first order degradation kinetic model, we are able to predict the long-term stability (up to 3 years) of multiple monoclonal antibody formulations. More specifically, we can robustly predict the long-term stability behaviour of a protein at the intended storage condition (5 °C), based on up to six months of data obtained for multiple quality attributes from different temperatures, usually from intended (5 °C), accelerated (25 °C) and stress conditions (40 °C). We have performed stability studies and evaluated the stability data of several mAbs including IgG1, IgG2, and fusion proteins, and validated our model by overlaying the 95% prediction interval and experimental stability data from up to 36 months. We demonstrated improved robustness, speed and accuracy of kinetic long-term stability prediction as compared to classical linear extrapolation used today, which justifies long-term stability prediction and shelf-life extrapolation for some biologics such as monoclonal antibodies. This work aims to contribute towards further development and refinement of the regulatory landscape that could steer toward allowing extrapolation for biologics during the developmental phase, clinical phase, and also in marketing authorisation applications, as already established today for small molecules.

Nanoparticulate Mycophenolic Acid Eye Drops - Analytical Validation of a High Performance Liquid Chromatography Assay and Stability Studies.

Mycophenolic acid (MPA), an immunosuppressive agent, is used orally to reduce corneal graft rejection. However, its oral use is associated with gastrointestinal side effects. This study aims to prepare: MPA nanoparticle eye drops and a validated analytical method. Aqueous MPA eye drops were prepared by nanoencapsulation of MPA using nanomerics MET (N-palamitoyl-N-monomethyl-N,N-dimethyl-N,N,N-trimethyl-6-O-glycolchitosan) at a MET and MPA ratio of 7.5: 1 g g-1 in the presence of glycerol (2.75% w/w). A validated MPA formulation drug substance assay was then conducted. MET-MPA formulations were prepared as well as a validated assay. Assay validation parameters for the analysis of MPA in the formulation were satisfactory [Plate count = 16458, capacity Factor = 2.4, Tailing Factor = 1.02, linearity = 0.999 (0.016-0.5 mg mL-1), limit of detection = 0.056 mg mL-1, limit of quantification = 0.17 mg mL-1, accuracy = 98%, intraday and interday relative standard deviation = 0.45% and 4% respectively]. The candidate formulation (z-average mean = 66 ± 0.4 nm, polydispersity index = 0.12 ± 0.012, drug content = 1.14 ± 0.003 mg mL-1, zeta potential = +8.5 ± 1.4 mV, pH = 7.4 ± 0.02, osmolarity = 309 ± 1.5 mOSm L-1, viscosity = 1.04 ± 0.001 mPa.s) was then found to be stable for 14 days with respect to drug content at refrigeration, room and accelerated (40ºC) temperature. All other formulation parameters were within the ocular comfort range. A validated assay (ICH and US FDA guidelines) for new MPA nanoparticle eye drops has been developed.

An Algorithmic Approach for Identifying Critical Distance Relays for Transient Stability Studies

After major disturbances, power system behavior is governed by the dynamic characteristics of its assets and protection schemes. Therefore, modeling protection devices is essential for performing accurate stability studies. Modeling all the protection devices in a bulk power system is an intractable task due to the limitations of current stability software, and the difficulty in updating the setting data for thousands of protection devices. One of the critical protection schemes that is not adequately modeled in stability studies is distance relaying. Therefore, this paper proposes an iterative algorithm that uses two methods to identify the critical distance relays to be modeled in stability studies: (i) apparent impedance monitoring, and (ii) the minimum voltage evaluation (MVE). The algorithm is implemented in Python 3.6 and uses the GE positive sequence load flow analysis (PSLF) software for performing stability studies. The performance of the algorithm is evaluated on the Western Electricity Coordinating Council (WECC) system data representing the 2018 summer-peak load. The results of the case studies representing various types of contingencies show that to have an accurate assessment of system behavior, modeling the critical distance relays identified by the algorithm suffices, and there is no need for modeling all the distance relays.

Dynamic Simulation of Eastern Regional Grid of India using Power System Simulator for Engineering PSS®E

Abstract Eastern Regional (ER) grid of India is one of the five regional grids consisting of voltage level 765 kV, 400 kV, 220 kV and numerous buses at lower voltage range. ER grid is the backbone of the Indian Grid as it is one of the main power generating hubs. Stability of the Indian Grid depends a lot on ER grid as it is the core of the generation and transmission system. For performing stability studies and to determine the weak area of the grid generally L-Index method is used. For detailed analysis like computation of voltage recovery time, maximum frequency deviation and critical clearing time of the buses of the system L-Index method is not suitable. Hence dynamic simulation is performed as it provides options to compute various parameters of ER Grid. The system has been studied using 197 buses of voltage levels 220 kV and above and transmission lines running over a length of 23,693 km. In this paper the power flow modelling, simulation and analysis of the Eastern Grid of India is performed. L-Index algorithm along with dynamic simulation provides the scope of computation of voltage recovery time, maximum frequency deviation and critical clearing time (by introducing an initial transient disturbance) along with the prediction of weak area of the system which gives a complete picture of transient stability of ER Grid.

Experimental Studies on Thermal Performance and Thermo-Structural Stability of Steelmaking Slag as Inventory Material for Thermal Energy Storage

Thermal energy storage (TES) systems are key components for concentrated solar power plants to improve their dispatchability and for shifting the energy production efficiently to high revenue periods. The commercial state of the art is the molten salt two tank storage technology. However, this TES confronts some issues like freezing and decomposition, which require continued technical attention. Furthermore, the molten salt itself is very expensive compared to other storage materials. A TES option that possesses a high cost reduction potential and the ability to increase the whole power plant efficiency is the regenerator-type energy storage. Here, a packed bed inventory of waste metallurgical slag from electric arc furnace (EAF) can achieve further cost reduction. Despite previous studies regarding the use of steelmaking slag as an inventory material for thermal energy storages, there are still basic questions to be answered. This work presents experimental thermal performance and thermo-structural stability studies of slag-based TES, obtained during the European project REslag. The EAF slag and different insulation options were tested for their thermomechanical strength in a uniaxial compression test rig. The thermal cyclic behavior was investigated in a pilot TES plant with temperatures up to 700 °C. The experimental results confirm the suitability of steelmaking slag as thermal energy storage inventory material. Furthermore, a comparison of experimental and simulation model results shows an agreement of over 90%.

Simultaneous Estimation of Aspirin, Atorvastatin Calcium and Clopidogrel Bisulphate in a Combined Dosage form by RP-HPLC

A rugged robust RP-HPLC method has been developed and validated for the simultaneous quantification of Aspirin (ASP), Atorvastatin calcium (ATO) and Clopidogrel bisulphate (CLO) in a combined dosage form. Optimized mobile phase composition of 25 mM KH2PO4: Methanol (20:80% v/v) pH 3.0 (adjusted with 20% o-phosphoric acid) isocratic mode with flow rate of 1 ml min-1, detection at 230 nm. Employed Princeton SPHER C18 (150 x 4.6 mm i.d. 5 µm) column for separation at ambient temperature with an isocratic flow. The linearity of each drug across the range of 0.5-32 µg/ml with correlation coefficient for ASP, ATO, and CLO in value of 0.979, 0.988 and 0.989 respectively. The retention time (min.) for ASP, ATO and CLO were found 1.85, 3.04 and 6.91 respectively. Limit of detection (LOD) of ASP, ATO and CLO - 0.04, 0.04, 0.08 (μg ml-1) respectively and Limit of Quantification (LOQ) of ASP, ATO and CLO- 0.14, 0.13, 0.28 (μg ml-1) in order. Performed analysis of marketed tablet formulation ASP (Ecosprin-75 mg), ATO (Aztor®40- 40 mg), CLO (Clopivas- 75 mg) found percentage recovery for ASP (99.93), ATO (100.00) and CLO (99.87). Performed stability studies found satisfactory results. Developed method has been validated, results of different parameter found in acceptable range. Chromatogram peaks are resolve, symmetric shape and without interference.

Optimized transformation, overexpression and purification of S100A10.

As a member of the S100 protein family, S100A10 has already been purified. However, its purity, or even yield, haveoften not beenreported in the literature. To facilitate future biophysical experiments with S100A10, we aimed to obtain it at a purity of at least 95% in a reasonably large amount. Here, we report optimized conditions for the transformation, overexpression and purification of the protein. We obtained a purity of 97% and performed stability studies by circular dichroism. Our data confirmed that the S100A10 obtained is suitable for experiments to be performed at room temperature up to several days.

Stability studies in oncology

Abstract Introduction: Hospital pharmacists, physicians, and nurses need stability information on the drugs used in their daily practice. The objectives of this work were to evaluate if the information given by pharmaceutical companies about the stability of reconstituted and diluted solutions in the field of oncology were sufficient in the daily practice of hospitals. Methods: The first step was to establish a list of the main needs about stability data on the basis of the daily practice of hospital pharmacists. The second step was to search through information given by pharmaceutical companies and then to compare to hospital pharmacists’ needs. The third step was to find information in the cases, in which pharmaceutical companies’ information was not sufficient. Results: The situation is different depending on the product. For originators, stability data given by pharmaceutical companies are often very limited, the goal being to obtain the marketing authorization. For generics or biosimilars, extended stability studies are carried out to conquer the market and are part of the marketing strategy. A list of studies to fill the gap of companies’ information was presented. Examples including bortezomib, rituximab, azacitidine, nivolumab, and some mixtures were presented. The importance of stability studies conducted in hospitals is emphasized. Conclusion: Pharmaceutical companies perform stability studies for their products and for their own interest. In many cases, the results of these studies are insufficient and do not meet the need for information that hospital pharmacists are looking for. Conducting stability studies by hospital pharmacy teams should be encouraged.