Development and multicenter validation of an LC-MS-based bioanalytical method for antisense therapeutics.

Background: Many bioanalytical methods for antisense oligonucleotides (ASOs) using LC-MS have been reported. However, no data have been available on the reproducibility and robustness of a single bioanalytical method for ASOs. As such, in the current study, we evaluated the reproducibility and robustness of LC-MS-based bioanalytical methods for ASOs in multiple laboratories. Methods/Results: Seven independent laboratories were included in this study. Mipomersen was measured by ion-pairing LC-MS (IP-LC-MS) as a model ASO using different LC-MS. The validation results of calibration curve, accuracy, precision and selectivity met the criteria of conventional bioanalytical method validation guidelines using LC/GC-MS for drugs in all laboratories. Meanwhile, carryover (>20%) was detected in three laboratories. Conclusion: We first demonstrated the multicenter-validated IP-LC-MS bioanalytical method for ASOs. Our data showed that the method was sensitive, robust and reproducible. However, the occurrence of carryover should be carefully monitored in its future application.

Bioanalysis of therapeutic monoclonal antibody by peptide adsorption-controlled LC-MS.

Aim: We aimed to develop an easy, low-cost and versatile mass spectrometric method for the bioanalysis of a therapeutic monoclonal antibody (mAb) in human serum that employs peptide adsorption-controlled (PAC)-LC/MS using selected reaction monitoring mode (LC-MS/MS-SRM). Materials & methods: Rituximab was used as a model mAb. To apply the method to human serum samples, a peptide of the complementarity-determining region was selected as the surrogate peptide. The usefulness of PAC-LC-MS/MS-SRM was evaluated by a collaborative study. Results: The calibration curve ranged from 0.5 (or 1.0) to 1000.0 µg/ml. The selectivity, linearity, accuracy and precision met the predefined acceptance criteria. Conclusion: Our method could be a useful bioanalytical method for the quantification of mAbs in clinical samples.

Basic considerations on the practical method for predicting sound insulation performance of a single-leaf window.

As a basic study of a practical method for predicting the sound insulation performance of windows, this report presents a study of the sound reduction index of windows with single glazing, below a critical frequency. First, the results calculated by an existing theory for a single plate for the sound reduction indices are compared with measured results of actual windows to assess the theory's applicability for evaluating the sound insulation performance of windows. Then, a regression analysis is employed to measure the results of a certain number of actual windows to explore a further development of a more practical prediction. The following findings were obtained: (1) Sound reduction indices of actual fixed windows are predictable using Sewell's transmission theory for a single plate. However, sound reduction indices of openable windows, especially those of sliding windows, are strongly affected by gaps in the window frame. Therefore, predicting sound reduction indices of all windows accurately is difficult if using only one theory. (2) The frequency slope of the window reduction index is much lower than that of the mass law. Regression analyses indicate that the frequency slope of the reduction index of all examined windows is 3.0 dB per octave, on average.

Application of transparent microperforated panels to acrylic partitions for desktop use: A case study by prototyping.

There are various measures currently in place to prevent the spread of coronavirus (COVID-19); however, in some cases, these can have an adverse effect on the acoustic environment in buildings. For example, transparent acrylic partitions are often used in eating establishments, meeting rooms, offices, etc., to prevent droplet infection. However, acrylic partitions are acoustically reflective; therefore, reflected sounds may cause acoustic problems such as difficulties in conversation or the leakage of conversation. In this study, we performed a prototyping of transparent acrylic partitions to which a microperforated panel (MPP) was applied for sound absorption while maintaining transparency. The proposed partition is a triple-leaf acrylic partition with a single acrylic sheet without holes between two MPP sheets, as including a hole-free panel is important to prevent possible droplet penetration. The sound absorption characteristics were investigated by measuring the sound absorption in a reverberation room. As the original prototype showed sound absorption characteristics with a gentle peak and low values due to the openings on the periphery, it was modified by closing the openings on the top and sides. The sound absorption performance was improved to some extent when the top and sides were closed, although there remains the possibility of further improvement. For this study, only the sound absorption characteristics were examined in the prototype experiments. The effects during actual use will be the subject of future study.

Development of a bioanalytical method for an antisense therapeutic using high-resolution mass spectrometry.

Background: Ion-pairing reverse-phase LC coupled with high-resolution mass spectrometry (IP-LC/HRMS) has gained attention in oligonucleotide therapeutic bioanalyses owing to its high sensitivity and selectivity. However, optimization and validation of IP-LC/HRMS-based methods are rare. The objective of this study is the development of a sensitive and reproducible IP-LC/HRMS-based bioanalytical method using clinically approved mipomersen as a model for antisense oligonucleotides. Materials & methods/results: Mipomersen was extracted from rat plasma using Clarity OTX SPE and quantified by IP-LC/HRMS. The calibration range was 0.5-250.0 ng/ml. The developed method met the general regulatory criteria for accuracy, precision, carry-over, selectivity, matrix effect and dilution integrity. Conclusion: A highly sensitive and reliable method for mipomersen measurement with potential antisense oligonucleotide bioanalysis applications has been developed.

Human plasma concentration-time profiles of troglitazone and troglitazone sulfate simulated by in vivo experiments with chimeric mice with humanized livers and semi-physiological pharmacokinetic modeling.

Troglitazone and its major metabolite troglitazone sulfate were intravenously administered to chimeric mice with different ratios of liver replacement by human hepatocytes. Total clearances were converted to hepatic intrinsic clearances normalized to their liver weight, with the assumption that extra-hepatic elimination of these compounds was negligible. These values were plotted against the replacement indices, and postulated values for virtual 100% chimeric mice were assumed to be equivalent to those in humans. Metabolic formation ratio was estimated by comparing AUCs of troglitazone sulfate after separate administration of troglitazone and troglitazone sulfate. Liver to plasma concentration ratios were obtained from direct measurement. These parameters were extrapolated to 100% chimeric mice and subjected to semi-physiological pharmacokinetic modeling using pharmacokinetic parameters for oral administration taken from literature. Our simulated plasma concentration-time profile of troglitazone agreed well with observed values obtained in clinical study. However, the profile of troglitazone sulfate was far below the reported values. Although the possible reasons for this discrepancy remains unsolved, the combination of chimeric mice with semi-physiological PK modeling proved to be a useful tool in understanding the function of each PK parameter in human pharmacokinetics of troglitazone and its conjugated metabolite.

Generic MS-based method for the bioanalysis of therapeutic monoclonal antibodies in nonclinical studies.

Aim: A generic bioanalytical method was developed to quantify therapeutic IgG1 monoclonal antibodies (mAbs) in mouse sera by combining an easy sample preparation method with LC/MS using selected reaction monitoring. Materials & methods: Rituximab and trastuzumab were used as model mAbs. A synthetic stable isotope-labeled peptide or a stable isotope-labeled mAb was used as an internal standard. The method feasibility was evaluated by a collaborative study involving six laboratories. Results: The calibration curve ranged from 1.0 to 1000.0 µg/ml (correlation coefficient >0.99). The validation parameters including selectivity, linearity of calibration curve, accuracy and precision met the predefined acceptance criteria. Conclusion: Our method is a useful bioanalytical method for the quantification of therapeutic IgG mAbs in nonclinical animal studies.

Some considerations on the use of space sound absorbers with next-generation materials reflecting COVID situations in Japan: additional sound absorption for post-pandemic challenges in indoor acoustic environments.

In this study, we first point out the possible acoustic problems associated with the post-pandemic operation of built environments. In particular, we focus on the problem of acoustic deficiency due to the lack of absorption. This deficiency, which is likely to be encountered in most enclosed spaces in a range of establishments, is due to the reduced number of audience members or users of the space as a result of social distancing. As one of the promising solutions to this problem, we introduce a sound absorption technique using three-dimensional (3D) space sound absorbers developed through our recent research projects. Significantly, the type of sound absorber proposed herein is made of materials that are especially suited to hygiene considerations. The materials are microperforated panels (MPPs) and permeable membranes (PMs), both of which are easily washable and sanitised. Furthermore, we point out that 3D-MPP or PM space absorbers possess the additional value of aesthetic designability.

Establishment of the Global SEND Alliance (G-SEND) in Japan and efficient creation of electronic SEND datasets between CROs.

The Standard for Exchange of Nonclinical Data (SEND), adopted by the US Food and Drug Administration (FDA), is a set of regulations for digitalization and standardization of nonclinical study data; thus, related organizations have begun implementing processes in support of SEND. The Global Editorial and Steering Committee (GESC), which provides oversight of the International Harmonization of Nomenclature and Diagnostic Criteria (INHAND), has prepared the SEND Controlled Terminology (CT) for toxicologic pathology. SEND provides electronic data standards created by the Clinical Data Interchange Standards Consortium (CDISC), and CDISC also collaborates in the implementation of SEND. Furthermore, the Pharmaceutical Users Software Exchange (PhUSE), which includes members of the US FDA, has conducted various activities to promote realistic and effective methods to implement SEND. As we reported in 2015, there is a significant variation in the efficiency and quality of SEND data implementation across pharmaceutical companies and contractors (CROs) globally. To address this problem, the Global SEND Alliance (G-SEND) was established in August 2018 to facilitate the coordination and standardization of SEND datasets across CROs in Asia. This paper reports the first method for organizationally and jointly creating consistent SEND datasets between CROs using G-SEND.

Development of a novel RANKL-based peptide, microglial healing peptide1-AcN (MHP1-AcN), for treatment of ischemic stroke.

Although the regulation of post-ischemic inflammation is an important strategy to treat ischemic stroke, all clinical trials have failed to show its efficacy. To solve the problem, we previously developed a novel partial peptide of RANKL, microglial healing peptide 1 (MHP1), which could reduce ischemic injury by inhibiting Toll-like receptor (TLR) induced inflammation. However, optimization of the peptide was necessary to increase the stability and efficacies for clinical use. According to information gathered through HPLC/MS in serum, we have newly designed a series of modified MHP1 peptides and have found that N-terminal acetylation and C-terminal amidation in MHP1 (MHP1-AcN), can strengthen its anti-inflammatory effects and increase its stability with anti-osteoclastogenic effects. Anti-TLR activity was reported to be reduced in MHP1 when incubated at 37 °C for 24 hrs, but MHP1-AcN could keep the activity under the same condition. The therapeutic effect of MHP1-AcN was observed in transient ischemic stroke model at lower dose than MHP1. Importantly, MHP1-AcN did not affect thrombolytic effects of tissue plasminogen activator (tPA) and inhibited tPA-induced hemorrhagic transformation. These findings indicated that MHP1-AcN was stable and effective anti-TLR signal peptide and could be a promising agent for treating stroke patients receiving tPA and endovascular therapy.

Simulation of human plasma concentration-time profiles of the partial glucokinase activator PF-04937319 and its disproportionate N-demethylated metabolite using humanized chimeric mice and semi-physiological pharmacokinetic modeling.

1. The partial glucokinase activator N,N-dimethyl-5-((2-methyl-6-((5-methylpyrazin-2-yl)carbamoyl)benzofuran-4-yl)oxy)pyrimidine-2-carboxamide (PF-04937319) is biotransformed in humans to N-methyl-5-((2-methyl-6-((5-methylpyrazin-2-yl)carbamoyl)benzofuran-4-yl)oxy)pyrimidine-2-carboxamide (M1), accounting for ∼65% of total exposure at steady state. 2. As the disproportionately abundant nature of M1 could not be reliably predicted from in vitro metabolism studies, we evaluated a chimeric mouse model with humanized liver on TK-NOG background for its ability to retrospectively predict human disposition of PF-04937319. Since livers of chimeric mice were enlarged by hyperplasia and contained remnant mouse hepatocytes, hepatic intrinsic clearances normalized for liver weight, metabolite formation and liver to plasma concentration ratios were plotted against the replacement index by human hepatocytes and extrapolated to those in the virtual chimeric mouse with 100% humanized liver. 3. Semi-physiological pharmacokinetic analyses using the above parameters revealed that simulated concentration curves of PF-04937319 and M1 were approximately superimposed with the observed clinical data in humans. 4. Finally, qualitative profiling of circulating metabolites in humanized chimeric mice dosed with PF-04937319 or M1 also revealed the presence of a carbinolamide metabolite, identified in the clinical study as a human-specific metabolite. The case study demonstrates that humanized chimeric mice may be potentially useful in preclinical discovery towards studying disproportionate or human-specific metabolism of drug candidates.

Relationship between sound radiation from sound-induced and force-excited vibration: Analysis using an infinite elastic plate model.

Although sound radiation from sound-induced vibration and from force-excited vibration of solid structures are similar phenomena in terms of radiating from vibrating structures, the general relationship between them has not been explicitly studied to date. In particular, airborne sound transmission through walls and sound radiation from structurally vibrating surfaces in buildings are treated as different issues in architectural acoustics. In this paper, a fundamental relationship is elucidated through the use of a simple model. The transmission coefficient for random-incidence sound and the radiated sound power under point force excitation of an infinite elastic plate are both analyzed. Exact and approximate solutions are derived for the two problems, and the relationship between them is theoretically discussed. A conversion function that relates the transmission coefficient and radiated sound power is obtained in a simple closed form through the approximate solutions. The exact solutions are also related by the same conversion function. It is composed of the specific impedance and the wavenumber, and is independent of any elastic plate parameters. The sound radiation due to random-incidence sound and point force excitation are similar phenomena, and the only difference is the gradient of those characteristics with respect to the frequency.

Distinct effects of moisture and air contents on acoustic properties of sandy soil.

Knowledge of distinct effects of moisture content and air volume on acoustic properties of soil is sought to predict the influence of human activities such as cultivation on acoustic propagation outdoors. This work used an impedance tube with the two-thickness method to investigate such effects. For a constant moisture weight percentage, the magnitude of the characteristic impedance became smaller and the absorption coefficient became higher with increase of the air space ratio. For a constant air space ratio, the absorption coefficient became larger and the magnitude of the propagation constant became smaller with increasing moisture weight percentage.

Application of modified integration rule to time-domain finite-element acoustic simulation of rooms.

The applicability of the modified integration rule for time-domain finite-element analysis is tested in sound field analysis of rooms involving rectangular elements, distorted elements, and finite impedance boundary conditions. Dispersion error analysis in three dimensions is conducted to evaluate the dispersion error in time-domain finite-element analysis using eight-node hexahedral elements. The results of analysis confirmed that fourth-order accuracy with respect to dispersion error is obtainable using the Fox-Goodwin method (FG) with a modified integration rule, even for rectangular elements. The stability condition in three-dimensional analysis using the modified integration rule is also presented. Numerical experiments demonstrate that FG with a modified integration rule performs much better than FG with the conventional integration rule for problems with rectangular elements, distorted elements, and with finite impedance boundary conditions. Further, as another advantage, numerical results revealed that the use of modified integration rule engenders faster convergence of the iterative solver than a conventional rule for problems with the same degrees of freedom.