Publications by authors named "Junyan Ji"

Temperature cycling stability studies can be appropriately designed and utilized to ensure that drug product quality, efficacy, and safety are not compromised when materials are subjected to short term temperature excursions from intended storage that may occur during e.g., shipping, transport, or patient use.

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Oxidation is an important degradation pathway of protein drugs. The susceptibility to oxidation is a common concern for therapeutic proteins as it may impact product efficacy and patient safety. In this work, we used 2,2'-azobis (2-amidinopropane) dihydrochloride (AAPH) as an oxidative stress reagent to evaluate the oxidation of therapeutic antibodies.

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We have previously demonstrated that upregulation of Sonic hedgehog (SHH) expression in allergic airway epithelia essentially contributes to the goblet cell metaplasia and mucous hypersecretion. However, the mechanism underlying the upregulation of SHH expression remains completely unknown. In cultured human airway epithelial cells, IL-4/IL-13 but not IL-5 robustly induces the mRNA and protein expression of SHH and in turn activates SHH signaling by promoting the JAK/STAT6-controlling transcription of gene.

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A new class of highly potent biopharmaceutical drugs, antibody-drug conjugates (ADCs), has been proven to be clinically effective to treat oncologic diseases. ADCs contain 3 major components: the monoclonal antibody, cytotoxic drug, and chemical linker. THIOMAB™ drug conjugates and interchain-cysteine ADCs are common ADC platforms that apply thiol-maleimide chemistry via Michael addition to conjugate linker-drugs to cysteine residues.

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Unlabelled: Degradation of the surfactant polysorbate (PS) by enzyme impurities has been previously suggested as a mechanism for the formation of visible and subvisible particles that affect product quality. Although chemical degradation pathways of PS, such as oxidation and acid/base hydrolysis, have been previously characterized, enzymatic degradation of PS remains poorly understood. In this report, enzyme-mediated hydrolysis of the major components of PS was monitored using an evaporative light scattering detection-high-performance liquid chromatography method.

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Polysorbates (PSs), as acquired from manufacturing processes and chemical nature of fatty acids (FAs) used in production of biotherapeutic formulations, are heterogeneous mixtures of structurally related compounds, covering a wide range of physicochemical properties. Such complexity presents a certain challenge for analysis of these important surfactants and demands the use of methods offering sufficient resolution to monitor individual classes of species and detect changes upon stress. A liquid chromatography mass spectrometry method, benefiting from the use of low m/z marker ions, simplifies profiling of PSs by providing detailed information on FA composition even of chromatographically overlapping peaks.

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Polysorbates (PSs), as acquired from manufacturing processes and chemical nature of fatty acids (FAs) used in production of biotherapeutic formulations, are heterogeneous mixtures of structurally related compounds, covering a wide range of physicochemical properties. Such complexity presents a certain challenge for analysis of these important surfactants and demands the use of methods offering sufficient resolution to monitor individual classes of species and detect changes upon stress. A liquid chromatography mass spectrometry method, benefiting from the use of low m/z marker ions, simplifies profiling of PSs by providing detailed information on FA composition even of chromatographically overlapping peaks.

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The long serum half-lives of mAbs are conferred by pH-dependent binding of IgG-Fc to the neonatal Fc receptor (FcRn). The Fc region of human IgG1 has three conserved methionine residues, Met252, Met358, and Met428. Recent studies showed oxidation of these Met residues impairs FcRn binding and consequently affects pharmacokinetics of therapeutic antibodies.

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Polysorbate 20 is a nonionic surfactant commonly used in the formulation of therapeutic monoclonal antibodies (mAb) to prevent protein denaturation and aggregation. It is critical to understand the molecular heterogeneity and stability of polysorbate 20 in mAb formulations as polysorbate can gradually degrade in aqueous solution over time by multiple pathways losing surfactant functions and leading to protein aggregation. The molecular heterogeneity of polysorbate and the interference from proteins and the excipient in the formulation matrix make it a challenge to study polysorbate in protein formulations.

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Polysorbate 20 (PS-20) is often included in the formulation for therapeutic proteins to reduce protein aggregation and surface adsorption. During the production process of therapeutic proteins, various membrane filters are used to filter product pools containing PS-20. The purpose of this study is to quantify the effects of these membrane filtration processes on the concentration and composition of PS-20.

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The oxidation of PTH(1-34) catalyzed by ferrous ethylenediaminetetraacetic acid (EDTA) is site-specific. The oxidation of PTH(1-34) is localized primarily to the residues Met[8] and His[9]. Beyond the transformation of Met[8] and His[9] into methionine sulfoxide and 2-oxo-histidine, respectively, we observed a hydrolytic cleavage between Met[8] and His[9].

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The physical stability of an immunoglobulin G4 monoclonal antibody (mAb) upon dilution into intravenous (i.v.) bags containing 0.

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2,2'-Azobis(2-amidinopropane) dihydrochloride (AAPH), a free radical-generating azo compound, is gaining prominence as a model oxidant in small molecule and protein therapeutics, namely for its ability to initiate oxidation reactions via both nucleophilic and free radical mechanisms. To better understand its degradation pathways, AAPH was degraded at 40°C in aqueous solutions over a wide pH range. Samples were analyzed via liquid chromatography-ultraviolet spectroscopy and liquid chromatography-tandem mass spectrometry (LC-MS/MS).

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Polysorbates (PS) are widely used as oil-in-water emulsifiers, stabilizers, wetting agents, solubilizers, and dispersants in the agricultural, food, personal care, and pharmaceutical industries due to their cost effectiveness, biocompatibility, formulation flexibility, low toxicity, and good stabilizing and protecting properties. The polysorbates are often pictured as polyoxyethylated sorbitan monoesters of saturated and/or unsaturated fatty acids. In reality, polysorbates are complex mixtures of multiple components, as follows from the reactions involved in their production.

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The physicochemical stability of protein therapeutics is of significant pharmaceutical interest. Immunoglobulin gamma (IgG) hinge region fragmentation has recently garnered attention as an important degradation route of therapeutic monoclonal antibodies. In this work, the rates and relative amount of fragment species are compared for five different IgGs (IgG1-5) with widely varying solution properties.

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Polysorbate 20 (polyoxyethylenesorbitan monolaurate) and polysorbate 80 (polyoxyethylenesorbitan monooleate) used in protein drug formulations are complex mixtures that have been difficult to characterize. Here, two HPLC methods are used with evaporative light scattering detection (ELSD) and mass spectrometry (MS) to characterize polysorbate from commercial vendors. The first HPLC method used a mixed-mode stationary phase (Waters Oasis MAX, mixed-mode anion exchange and reversed-phase sorbent) with a step gradient to quantify both the total polyoxyethylene sorbitan ester and polyoxyethylene sorbitan (POE sorbitan, a non-surfactant) in polysorbate.

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Purpose: To study recombinant human vascular endothelial growth factor (rhVEGF), the release characteristics from topical gel formulations, and its interaction with the gelling agents.

Methods: The release kinetics were followed by quantifying rhVEGF that diffused into the receptor chamber of Franz cells. Analytical ultracentrifuge (AUC) was used to characterize the sedimentation velocity of rhVEGF experienced in the gel.

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Methylcellulose and hydroxypropylmethylcellulose (hypromellose) are used in topical formulations of a protein to form a viscous hydrogel. Five lots of hypromellose raw material were made into 3% gel; all showed viscosity loss after sterilization by autoclave. EDTA (edetate disodium) minimized the viscosity loss caused by autoclaving in the presence of up to 100 ppm H(2)O(2).

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Recent oxidation events on monoclonal antibody candidates prompted us to investigate the mechanism of oxidation of Met, Trp, and His residues and to search for suitable stabilizers. By using parathyroid hormone (1-34), PTH, as a model protein and various oxidants, aided by liquid chromatography, peptide mapping, and mass spectrometry, we identified and quantified the oxidation of these vulnerable residues. Whereas H(2)O(2) and t-butyl hydroperoxide (t-BHP) primarily oxidized the two Met residues, 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH), and H(2)O(2) + Fe(II) oxidized Met and Trp residues, with AAPH more capable of generating oxidized Trp species than the latter.

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The compatibility between several dressing materials and a recombinant human vascular endothelial growth factor (rhVEGF) topical methylcellulose gel formulation was investigated. The dressings being studied were Adaptic, Non-stick Dressing, Conformant 2, Opsite and Tegapore. The criteria to select a compatible dressing include protein stability, absence of leachables from the dressing, and ability to retain gel on wound.

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