Advantages of application of UPLC in pharmaceutical analysis.

Ultra Performance Liquid Chromatography (UPLC) is a relatively new technique giving new possibilities in liquid chromatography, especially concerning decrease of time and solvent consumption. UPLC chromatographic system is designed in a special way to withstand high system back-pressures. Special analytical columns UPLC Acquity UPLC BEH C(18) packed with 1.

Separation and determination of terbinafine and its four impurities of similar structure using simple RP-HPLC method.

A novel reversed-phase HPLC method for the simultaneous determination of active component terbinafine, its one impurity 1-methylaminomethylnaphtalene and three degradation products, beta-terbinafine, Z-terbinafine and 4-methyl-terbinafine occurring in pharmaceutical formulations after long-term stability tests, was developed and validated using propylparaben as an internal standard. The chromatographic separation was performed on a NUCLEOSIL 100-5-CN column, mobile phase for separation of all compounds consisted of a mixture of tetrahydrofurane, acetonitrile and citrate buffer pH 4.50 (10:20:70,v/v/v).

Analysis of phenolic compounds by high performance liquid chromatography and ultra performance liquid chromatography.

Two novel chromatographic methods both based on utilization of sub-2-micron particle columns were developed for the analysis of phenolic compounds in this work. An HPLC system was equipped with C(18) silica-based analytical column (50 mm x 4.6 mm, 1.

Hydrophilic interaction liquid chromatography method for the determination of ascorbic acid.

Hydrophilic interaction liquid chromatography (HILIC) method using internal standard for the determination and stability study of ascorbic acid was developed. HILIC method was very fast and simple using the following analytical conditions: ZIC HILIC (150 x 2.1 mm, 3.

CEBPA polymorphisms and mutations in patients with acute myeloid leukemia, myelodysplastic syndrome, multiple myeloma and non-Hodgkin's lymphoma.

The transcription factor CCAAT/enhancer binding protein (C/EBP)alpha is a myeloid-specific transcription factor which is required for normal myeloid differentiation. C/EBPalpha is encoded by an intronless gene that is 2783 bp long and maps to human chromosome 19q13.1.

Comparative study of non-invasive blood pressure measurement methods in elderly people.

Results obtained by the modern automatic blood pressure (BP) monitors using oscillometric method [5] are highly dependent on conditions of cardiovascular system of the monitored person. Especially, with people who suffer from cardiovascular diseases (e.g.

Low incidence of restrictive valvulopathy in patients with Parkinson's disease on moderate dose of pergolide.

Restrictive valvular heart disease (VHD) has recently been reported in Parkinson's disease (PD) patients treated with ergot dopamine agonists. The aim of the present study was to detect valvular changes in our patients and to investigate their relationship to long-term use of pergolide. We examined 90 patients (mean age 60.

Eukaryotic-type serine/threonine protein kinase StkP is a global regulator of gene expression in Streptococcus pneumoniae.

Signal transduction pathways in both prokaryotes and eukaryotes utilize protein phosphorylation as a key regulatory mechanism. Recent studies have proven that eukaryotic-type serine/threonine protein kinases (Hank's type) are widespread in many bacteria, although little is known regarding the cellular processes they control. In this study, we have attempted to establish the role of a single eukaryotic-type protein kinase, StkP of Streptococcus pneumoniae, in bacterial survival.

Comparison of a novel ultra-performance liquid chromatographic method for determination of retinol and alpha-tocopherol in human serum with conventional HPLC using monolithic and particulate columns.

Retinol and alpha-tocopherol are biologically active compounds often monitored in blood samples because of their evident importance in human metabolism. In this study a novel ultra-performance liquid chromatographic (UPLC) method used for determination of both vitamins in human serum has been compared with conventional HPLC with particulate and monolithic C(18) columns. In UPLC a sub-two-micron particle-hybrid C(18) stationary phase was used for separation, in contrast with a five-micron-particle packed column and a monolithic column with a highly porous structure.

A eukaryotic-type serine/threonine protein kinase StkP of Streptococcus pneumoniae acts as a dimer in vivo.

Streptococcus pneumoniae carries a single Ser/Thr protein kinase gene stkP in its genome. Biochemical studies performed with recombinant StkP have revealed that this protein is a functional membrane-linked eukaryotic-type Ser/Thr protein kinase. Here, we demonstrate that the deletion of its extracellular domain negatively affects the stability of a core kinase domain.

Increase in body weight is a non-motor side effect of deep brain stimulation of the subthalamic nucleus in Parkinson's disease.

Deep brain stimulation of the subthalamic nucleus (DBS STN) is an effective treatment method in advanced Parkinson's disease (PD) providing marked improvement of its major motor symptoms. In addition, non-motor effects have been reported including weight gain in PD patients after DBS STN. Using retrospective survey, we aimed to evaluate weight changes in our patients with advanced PD treated with DBS STN.

Advantages of ultra performance liquid chromatography over high-performance liquid chromatography: comparison of different analytical approaches during analysis of diclofenac gel.

Miniaturization embracing instrumentation, column particle size, and column dimensions is one of the major current trends in separation techniques. This leads to shortening of analysis time and great savings in solvent consumption. Ultra performance liquid chromatography (UPLC) is one of the new developments in liquid chromatography.

HPLC determination of chlorhexidine gluconate and p-chloroaniline in topical ointment.

A novel fast isocratic reversed-phase HPLC method for simultaneous determination of chlorhexidine and its degradation product p-chloroaniline was developed. Zorbax SB Phenyl column (75 mm x 4.6 mm, 3.

Lipid raft-based membrane compartmentation of a plant transport protein expressed in Saccharomyces cerevisiae.

The hexose-proton symporter HUP1 shows a spotty distribution in the plasma membrane of the green alga Chlorella kessleri. Chlorella cannot be transformed so far. To study the membrane localization of the HUP1 protein in detail, the symporter was fused to green fluorescent protein (GFP) and heterologously expressed in Saccharomyces cerevisiae and Schizosaccharomyces pombe.

Effect of phosphate on the expression of protein-Ser/Thr kinase pkg2 in Streptomyces granaticolor.

A time-correlated expression of eukaryotic-like protein Ser/Thr kinase Pkg2 of Streptomyces granaticolor was investigated by reverse transcriptase-polymerase chain reaction (RT-PCR) and by transcriptional fusion experiments. In a complex medium the activity of pkg2 promoter was constant during the life cycle. Direct RNA analysis proved the presence of corresponding pkg2 transcript.

HPLC determination of calcium pantothenate and two preservatives in topical cream.

A RP-HPLC method for simultaneous determination of calcium pantothenate and two preservatives methylparaben and propylparaben present in topical cream was developed. Different analytical columns with various stationary phases were tested. During method development, Supelco Discovery C18 column (125 mmx4.

Determination of estradiol and its degradation products by liquid chromatography.

A novel HPLC method for simultaneous determination of estradiol and its seven degradation products in topical gel was developed. Zorbax SB-CN (150 mm x 4.6 mm, 5 microm) analytical column and mobile phase composed of acetonitrile, phosphoric acid 0.

A comparison of performance of various analytical columns in pharmaceutical analysis: conventional C18 and high throughput C18 zorbax columns.

New improved types of analytical columns Zorbax Eclipse XDB-C18 (75 mm x 4.6 mm i.d.

Differential effect of phosphatidylethanolamine depletion on raft proteins: further evidence for diversity of rafts in Saccharomyces cerevisiae.

A considerable amount of evidence supports the idea that lipid rafts are involved in many cellular processes, including protein sorting and trafficking. We show that, in this process, also a non-raft lipid, phosphatidylethanolamine (PE), has an indispensable function. The depletion of this phospholipid results in an accumulation of a typical raft-resident, the arginine transporter Can1p, in the membranes of Golgi, while the trafficking of another plasma membrane transporter, Pma1p, is interrupted at the level of the ER.

Development and validation of HPLC method for determination of indomethacin and its two degradation products in topical gel.

Indomethacin forms by decomposition two degradation products: 4-chlorobenzoic acid and 5-methoxy-2-methylindoleacetic acid. They have to be monitored together with an active substance both during manufacturing process and storage of pharmaceuticals. European Pharmacopoeia (Ph.

Characterization of a eukaryotic type serine/threonine protein kinase and protein phosphatase of Streptococcus pneumoniae and identification of kinase substrates.

Searching the genome sequence of Streptococcus pneumoniae revealed the presence of a single Ser/Thr protein kinase gene stkP linked to protein phosphatase phpP. Biochemical studies performed with recombinant StkP suggest that this protein is a functional eukaryotic-type Ser/Thr protein kinase. In vitro kinase assays and Western blots of S.

Comparison of performance of C18 monolithic rod columns and conventional C18 particle-packed columns in liquid chromatographic determination of Estrogel and Ketoprofen gel.

The performance of monolithic HPLC columns Chromolith (made by Merck, Germany) and conventional C18 columns Discovery (Supelco, Sigma-Aldrich, Prague, Czech Republic) was tested and the comparison for two topical preparations Ketoprofen gel and Estrogel gel was made. The composition of mobile phases - for Ketoprofen analysis a mixture of acetonitrile, water and phosphate buffer adjusted to pH 3.5 (40:58:2) and for Estrogel analysis a mixture of acetonitrile, methanol, water (23:24:53) - was usually not optimal for analyses at all types of columns.

Simultaneous HPLC determination of ketoprofen and its degradation products in the presence of preservatives in pharmaceuticals.

A novel and quick high-performance liquid chromatography (HPLC) method with UV spectrophotometric detection was developed and validated for the determination of five compounds in topical gel. The described method is suitable for simultaneous determination of active component ketoprofen, two preservatives methylparaben and propylparaben and two degradation products of ketoprofen--3-acetylbenzophenone and 2-(3-carboxyphenyl) propionic acid--in a topical cream after long-term stability tests using ethylparaben as an internal standard. The chromatographic separation was performed on a 5microm Supelco Discovery C18 column (125mm x 4mm i.

Behavioral and neuroendocrine changes during mental stress and repeated treatment with antidepressants in healthy men.

Excessive stress loadings in daily life are believed to play a role in the development of affective disorders. Our recent finding of enhanced neuroendocrine activation during stress of hypoglycemia after repeated antidepressant treatment in healthy men supports the hypothesis that the clinical effects of antidepressant treatment may be partly due to the adjustment of the stress response, which was reported to be blunted in depressive patients. The present double-blind placebo-controlled study investigated the effects of 6 days of treatment with the antidepressants citalopram or tianeptine on neuroendocrine activation during mental stress.

HPLC determination of estradiol, its degradation product, and preservatives in new topical formulation Estrogel HBF.

This paper deals with the development of a novel method for simultaneous determination of estradiol, its degradation product estrone, and two preservatives, methylparaben and propylparaben, in the topical preparation Estradiol HBF. After optimization of the analytical conditions the method was validated and applied in studies of the stability of the topical preparation Estrogel HBF. Separation of all these compounds was performed on a Supelco Discovery C18 (250 mm x 3.