Analysis of protamine peptides in insulin pharmaceutical formulations by capillary electrophoresis.

Protamines are a group of highly basic peptides that are sometimes added to insulin formulations to prolong the pharmacological action. In this study, different methods were investigated to identify protamine in insulin formulations. Capillary electrophoresis in aqueous and non-aqueous media was tested to separate these peptides with very close amino acid sequences.

Fully automated electrophoretically mediated microanalysis for CYP1A1 activity monitoring optimized by multivariate approach.

In this study, a fully automated incapillary system was developed to monitor the activity of CYP1A1 (Cytochrome P450, family 1, subfamily A, polypeptide 1) in physiological conditions. Ethoxycoumarin, the selected substrate, undergoes an inline bioreaction in the presence of CYP1A1 supersomes and Nicotinamide adenine dinucleotide phosphate reduced as cofactor, giving rise to hydroxycoumarin, the product that was assayed. The optimization of the experimental conditions was supported by the application of a design of experiment, providing a better understanding of electrophoretic mixing parameters that influence the metabolic reactions.

Separation of human, bovine, and porcine insulins, three very closely related proteins, by micellar electrokinetic chromatography.

Human, bovine, and porcine insulins are small proteins with very closely related amino acid sequences, which makes their separation challenging. In this study, we took advantage of the high-resolution power of CE, and more particularly of micellar electrokinetic chromatography, to separate those biomolecules. Among several surfactants, perfluorooctanoic acid ammonium salt was selected.

Simultaneous determination of insulin and its analogues in pharmaceutical formulations by micellar electrokinetic chromatography.

A simple and efficient MEKC method was developed to simultaneously determine human insulin, its five analogues, the main degradation products and the excipients usually present in injection formulations. A very fast method with a total analysis time of 3 min was then successfully validated for the analysis of human insulin and the quality control of commercial formulations was carried out.

In-capillary derivatization with (-)-1-(9-fluorenyl)ethyl chloroformate as chiral labeling agent for the electrophoretic separation of amino acids.

An original micellar electrokinetic chromatography (MEKC) method using in-capillary derivatization with a chiral labeling reagent was developed for the separation of amino acid (AA) derivatives. The potential of (-)-1-(9-fluorenyl)-ethyl chloroformate (FLEC) as in-capillary derivatization agent is described for the first time. Several parameters for in-capillary derivatization and subsequent MEKC separation were systematically investigated using experimental designs.

Development of a generic micellar electrokinetic chromatography method for the separation of 15 antimalarial drugs as a tool to detect medicine counterfeiting.

Since antimalarial drugs counterfeiting is dramatically present on the African market, the development of simple analytical methods for their quality control is of great importance. This work consists in the CE analysis of 15 antimalarials (artesunate, artemether, amodiaquine, chloroquine, piperaquine, primaquine, quinine, cinchonine, mefloquine, halofantrine, sulfadoxine, sulfalen, atovaquone, proguanil, and pyrimethamine). Since all these molecules cannot be ionized at the same pH, MEKC was preferred because it also allows separation of neutral compounds.

Chemo- and enantio-selective method for the analysis of amino acids by capillary electrophoresis with in-capillary derivatization.

A novel dual chiral CE method was developed for the separation of l- and d-amino acids (AAs), using in-capillary derivatization with 9-fluoroenylmethyl chloroformate (FMOC). Firstly, using pre-column derivatization, the enantioseparation of FMOC-AAs was optimized according to the nature of cyclodextrins (CD). A background electrolyte (BGE) composed of 30 mM β-CD, 30 mM octakis(2,3-dihydroxy-6-O-sulfo)-γ-CD (OS-γ-CD), 40 mM tetraborate and 15% isopropanol (IPA) was selected and led to 17 baseline resolved pairs (R(s)=1.

Micellar electrokinetic chromatography systems for the separation of mixtures of charged and uncharged compounds.

In this study, the migration behavior of charged and uncharged analytes was investigated under different conditions. Effective mobilities - electrophoretic mobilities under the influence of micelles - of cations, anions, and neutrals were measured at neutral, basic, and acidic pH (7.5, 11, and 2.

Contractile and electrophysiological properties of pulmonary artery smooth muscle are not altered in TASK-1 knockout mice.

The acid-sensitive, two-pore domain K+ channel, TASK-1, contributes to the background K+ conductance and membrane potential (Em) of rat and human pulmonary artery smooth muscle cells (PASMCs), but its role in regulating tone remains elusive. This study aimed to clarify the role of TASK-1 by determining the functional properties of pulmonary artery (PA) from mice in which the TASK-1 gene was deleted (TASK-1/3 KO), in comparison with wild-type (WT) C57BL/6 controls. Small vessel wire myography was used to measure isometric tension developed by intact PA.