Utility of High Resolution 2D NMR Fingerprinting in Assessing Viscosity of Therapeutic Monoclonal Antibodies.

PURPOSE: The viscosity of highly concentrated therapeutic monoclonal antibody (mAb) formulations at concentrations ≥ 100 mg/mL can significantly affect the stability, processing, and drug product development for subcutaneous delivery. An early identification of a viscosity prone mAb during candidate selection stages are often beneficial for downstream processes. Higher order structure of mAbs may often dictate their viscosity behavior at high concentration. Thus it is beneficial to gauge or rank-order their viscosity behavior using noninvasive structural fingerprinting methods and to potentially screen for suitable viscosity lowering excipients. METHODS: In this study, Dynamic Light Scattering (DLS) and 2D NMR based methyl fingerprinting were used to correlate viscosity behavior of a set of Pfizer mAbs. The viscosities of mAbs were determined. Respective Fab and Fc domains were generated for studies. RESULT: Methyl fingerprinting of intact mAbs allows for differentiation of viscosity prone mAbs from well behaved ones even at 30-40 mg/ml, where bulk viscosity of the solutions are near identical. For viscosity prone mAbs, peak broadening and or distinct chemical shift changes were noted in intact and fragment fingerprints, unlike the well-behaved mAbs, indicative of protein protein interactions (PPI). CONCLUSION: Fab-Fab or Fab-Fc interactions may lead to formation of protein networks at high concentration. The early transients to these network formation may be manifested through peak broadening or peak shift in the 2D NMR spectrum of mAb/mAb fragments. Such insights go beyond rank ordering mAbs based on viscosity behavior, which can be obtained by other methods as well..

It is ethical to diagnose a public figure one has not personally examined.

Should psychiatrists be able to speculate in the press or social media about their theories? John Gartner argues the risk to warn the public of concerns about public figures overrides the duty of confidentiality; whereas Alex Langford suggests this is beyond the ethical remit of psychiatric practice.Declaration of interestA.O'B is joint debates and analysis Editor of the British Journal of Psychiatry. J.G. is the founder of Duty To Warn, an association of mental health professionals who advocate the president's removal under the 25th Amendment on the grounds that he is psychologically unfit and dangerous.

Impact of Formulation and Suspension Properties on Redispersion of Aluminum-Adjuvanted Vaccines.

The adsorption of antigens to the surface of 2 commonly used insoluble adjuvants, aluminum phosphate and aluminum hydroxide, has been well characterized. In spite of the pharmaceutical benefits, alum-based vaccine formulations can present challenges in redispersion of the final product after storage. Inability to resuspend alum-based vaccines during administration results in inadequate dosing, thus rendering the product unusable. Here, the influence of formulation conditions on the resuspendability of aluminum adjuvant-containing vaccines was investigated. Particle size analysis by Micro-Flow Imaging (MFI™), zeta potential measurement, and sedimentation analysis by Turbiscan® were used to characterize suspension properties. Ionic strength, pH, and antigen concentration were found to significantly influence sedimentation behavior, particle size, and redispersion. Increasing ionic strength increased the sedimentation rate of adjuvants favoring resuspendability. The addition of bovine serum albumin to aluminum phosphate reduced resuspendability more significantly than the addition of lysozyme. Decreased resuspendability correlated with an increase in fine-to-large particle ratio and decrease in sedimentation rate. In summary, resuspendability of adjuvant drug product is favored by increased flocculation, decrease in fine-to-large particle ratio, and reduction in surface charge of antigen and adjuvant. A careful balance of these formulation conditions can therefore be an effective means to mitigate challenges of alum adjuvant redispersion.

Intermittent catatonia and complex automatisms caused by frontal lobe epilepsy in dementia.

An 82-year-old man was admitted to the emergency department following bizarre behaviour. Police had noticed him driving erratically through his village. He did not stop when instructed, drove slowly home and appeared 'vacant' on questioning. While in hospital, he had approximately 15 episodes of catatonia, involving rigidity, negativism, mutism except echolalia and perseveration, automatic obedience and utilisation phenomena, lasting 2-20 min each. Between episodes, he was amnestic but otherwise well. Electroencephalography demonstrated bifrontal slowing with left-sided emphasis, and captured two focal onset partial seizures with the clinical correlate of the syndrome described above. He improved rapidly on levetiracetam and lorazepam, was discharged and received a diagnosis of dementia by his community mental health team shortly afterwards, based on chronic short-term memory loss, functional decline and MRI changes. This case has implications for our understanding of the neural correlate of catatonia, specifically frontal lobe pathway dysfunction.

Trimerization Dictates Solution Opalescence of a Monoclonal Antibody.

Opalescence, sometimes observed in antibody solutions, is thought to be mediated by light scattering of soluble oligomers or insoluble particulates. However, mechanistic features, such as stoichiometry and self-association affinity of oligomeric species related to opalescence, are poorly understood. Here, opalescence behavior of a monoclonal antibody (mAb-1) solution was studied over a wide range of solution conditions including different protein concentrations, pH, and in the presence or absence of salt. Hydrodynamic and thermodynamic properties of mAb-1 solutions were studied by analytical ultracentrifugation and dynamic light scattering. Opalescence in mAb-1 solutions is pH and concentration dependent. The degree of opalescence correlates with reversible monomer-trimer equilibrium detected by analytical ultracentrifugation. Increased trimer formation corresponds to increased opalescence in mAb-1 solutions at higher pH and protein concentrations. Addition of NaCl shifts this equilibrium toward monomer and reduces solution opalescence. This study demonstrates that opalescence in mAb-1 solutions does not arise from the light scattering of monomer or random molecular self-associations but is strongly correlated with a specific self-association stoichiometry and affinity. Importantly, at pH 5.5 (far below isoelectric point of mAb-1), the solution is not opalescent and with nonideal behavior. This study also dissects several parameters to describe the hydrodynamic and thermodynamic nonideality.

Electrocution-induced atrial fibrillation: a novel cause of a familiar arrhythmia.

A previously fit and well 40-year-old man presented to the emergency department with palpitations after suffering an 11 000 volt electrical shock from overhead power cables through a mobile crane which he was operating. His ECG demonstrated the presence of new atrial fibrillation at a rate of 80 beats per min. He was haemodynamically stable, and had otherwise only sustained a small exit burn to his left great toe. Routine blood tests including creatine kinase and troponin T were normal. A bolus of intravenous flecainide failed to restore sinus rhythm, but an amiodarone infusion was successful. An electrical shock is a rare cause of atrial fibrillation. There is no consensus over optimal medical management. Numerous treatment plans have been previously employed with varying degrees of success.