Tag: <span>HPLC</span>

Physicochemical and Biological Evaluation of Bioadhesive Polymers for the Development of Intranasal Low Sialic Acid Erythropoietin Formulations

Low sialic acid erythropoietin (Neuro-EPO) is a nonerythropoietic molecule that shows neuroprotective activity in some rodent models for brain ischemia. One reason for poor absorption may be the rapid removal of the drug from the site of absorption by mucociliary clearance. For that reason, bioadhesive polymers are used to increase the residence time of the drug in the nasal cavity. The objective of the current study was to evaluate different bioadhesive polymers to identify Neuro-EPO formulations with characteristics suitable for nasal delivery. For this purpose, four different polymers: (1) hydroxypropyl methylcellulose (HPMC) F4M; (2) HPMC K4M; (3) Carbopol 974P; and (4) dextran 70 were assessed to define the appropriate concentration. The physicochemical evaluation of placebo formulations showed reductions in apparent viscosity, except with dextran 70. With dextran 70, the bioadhesive polymers interacted with other excipients such as buffers, isotonic agents, and antimicrobial preservatives. The decrease of apparent viscosity was observed significantly in the formulation with Carbopol 974P, which also showed the presence of instability. Formulations with Neuro-EPO and HPMC showed adequate physicochemical properties with the pH, isotonicity, and concentrations of protein by reverse-phase (RP) high-pressure liquid chromatography (HPLC), as expected. However, the formulation with dextran 70 showed chemical incompatibility, as evidenced by the reduction of protein concentration and purity. In the permanent unilateral ischemia model, a higher survival percentage was observed with formulations of HPMC F4M and HPMC K4M, evidenced by the analysis of neurology parameters. Both formulations were significantly different from their vehicle…

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Biologics Production

bioadhesive polymers biologics biosimilars carbopol 974p erythropoietin HPLC htmc hydroxypropyl methylcellulose intranasal epo formulations neuro-epo neuro-epo formulations

Signaling Substances Used in Plant Defense: HPLC-MS/MS Analysis of Jasmonates

Plants must be capable of responding to climatic fluctuations, diurnal rhythms, available supplies of water and nutrients, and insect attacks and infestations. To ensure such responses, plants need a network of regulating substances called phytohormones. These substances enable plants to respond to both biotic and abiotic stresses by initiating a cascade of orchestrated actions, and to trigger development-specific processes. In this article, we will discuss a highly sensitive analytical method for quantitative determination of phytohormones. The main representatives of the plant hormones are jasmonic acid (JA), cytokines, auxins, abscisic acid, salicylic acid, gibberellins, and strigolactones.

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Biologics Research

HPLC hplc-ms mass spectrometry nanoESI-MS plant signaling sartorius ultrapure water

Separation and Characterization of a Monoclonal IgG2 Antibody by Cation Exchange Chromatography

Cation exchange chromatography (CEX) is a versatile method for separation of proteins based on exploiting differences in positive electrostatic charges. In CEX, proteins are bound to the negatively charged stationary phase (cation exchangers) and then eluted using a salt gradient. Typically, the liquid-phase pH in CEX is lower than the isoelectric points (pI) of the proteins. CEX has been used to monitor various post-translational modifications such as glycosylation, deamidation, phosphorylation, truncation, oxidation, C-terminal and N-terminal clipping, and N-terminal cyclization. Some of these variants may exhibit different bioactivity. Therefore, it is important to characterize protein variants and monitor the stability of these variants throughout the process of drug discovery, development, and manufacture. Characterization of complex proteins such as antibodies, has traditionally been performed using slab gel-based techniques such as isoelectric focusing (IEF). This technique is qualitative and time consuming. It also generates large quantities of chemical waste from the staining process…

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Biologics Production

cation exchange chromatography characterization chromatography HPLC monoclonal antibody separation