Theoretical interpretation of retention data of polychlorinated biphenyls in liquid chromatography

1991 ◽  
Vol 56 (12) ◽  
pp. 2833-2848
Author(s):  
Vladimír Jakuš ◽  
Stanislav Miertuš
Keyword(s):  
Polychlorinated Biphenyls ◽  
Biologically Active ◽  
Dominant Factor ◽  
Theoretical Interpretation ◽  
Retention Data ◽  
Theoretical Evaluation ◽  
Retention Model ◽  
New Approach ◽  
Rp Hplc ◽  
Mobile Phases

The new approach to the theoretical evaluation of Gibbs free energy of solvation is applied to the estimation of retention data in RP-HPLC. Simple models of stationary and mobile phases in RP-HPLC are used. The correlation between retention data of a series of 15 polychlorinated biphenyls (measured on chemically bonded stationary phase with C18 alkyl chains) and the contribution of the Gibbs solvation energy is investigated in order to determine the dominant factor controlling retention. The retention in RP-HPLC can be predicted on the basis of our thermodynamic retention model. This approach is suitable especially when no standards are available for some derivatives (e.g. metabolites of biologically active substances) and when the interpretation of experimental elution is not clear.

Theoretical Interpretation of High-Performance Chromatographic Data for a Heterogeneous Series of Compounds

1992 ◽  
Vol 57 (1) ◽  
pp. 33-45
Author(s):  
Vladimír Jakuš
Keyword(s):  
Experimental Data ◽  
High Performance ◽  
Theoretical Interpretation ◽  
Retention Data ◽  
Theoretical Evaluation ◽  
New Approach ◽  
Free Energy Of Solvation ◽  
Rp Hplc ◽  
Mobile Phases ◽  
Reversed Phases

A new approach to theoretical evaluation of the Gibbs free energy of solvation was applied for estimation of retention data in high-performance liquid chromatography on reversed phases (RP-HPLC). Simple and improved models of stationary and mobile phases in RP-HPLC were employed. Statistically significant correlations between the calculated and experimental data were obtained for a heterogeneous series of twelve compounds.

scholarly journals Development and Validation of Stability-Indicating RP-HPLC Method for the Estimation of Lenalidomide and its Impurities in Oral Solid Dosage Form

2019 ◽  
Vol 35 (1) ◽  
pp. 140-149 ◽  
Author(s):  
Somana Siva Prasad ◽  
G. V. Krishna Mohan ◽  
A. Naga Babu
Keyword(s):  
Limit Of Detection ◽  
Degradation Products ◽  
Pharmaceutical Formulations ◽  
Hplc Method ◽  
Stability Robustness ◽  
Rp Hplc ◽  
Mobile Phases ◽  
Limit Of Quantitation ◽  
Successful Separation ◽  
Quality By Design Approach

In this study, a novel, simple and precise RP-HPLC method has been developed for the quantitative analysis of Lenalidomide (LLM) in pharmaceutical formulations using analytical quality by design approach. An X-bridge-C18 column (150 mm × 4.6 mm × 3.5 µ) with mobile phases containing a Potassium dihydrogen orthophosphate anhydrous buffer and methanol in the ratio of (90:10 v/v) and (35:65 v/v) are used for the estimation of LLM and its degradation products. The flow rate of 0.8 mL/min is maintained and all degradation studies are performed at 210 nm using photodiode array (PDA) detector. Method Validation is carried out according to International Council for Harmonisation (ICH) guidelines and the parameters namely; precision, accuracy, specificity, stability, robustness, linearity, limit of quantitation (LOQ) and limit of detection (LOD) are evaluated. The present developed RP-HPLC method shows the purity angle of peaks is less than their threshold angle, signifying that it to be suitable for stability studies. Hence, the developed method can be used for the successful separation of LLM and its impurities in the pharmaceutical dosage formulations.

Nickel(II)- and Silver(I)-Catalyzed C–H Bond Halogenation of Anilides and Carbamates

Synthesis ◽  
2020 ◽  
Author(s):  
Ebrahim Kianmehr ◽  
Hadi Afaridoun
Keyword(s):  
Biologically Active Compounds ◽  
Biologically Active ◽  
Silver Catalyst ◽  
Active Compounds ◽  
Available N ◽  
New Approach

Abstract ortho-C–H bond halogenation of anilides and N-aryl carbamates using easily available N-halosuccinimides (NXS) as the active halogenation reagent in the presence of nickel or silver catalyst has been developed. This method provides a new approach to 2-haloanilides and carbamates, which may serve as starting materials for the synthesis of pharmaceutically and biologically active compounds.

A NEW APPROACH FOR INVESTIGATING HYPOTHALAMO-PITUITARY-GONADAL AND ADRENAL FEEDBACK CONTROL MECHANISMS: ACTIVE IMMUNIZATION WITH STEROIDS

1974 ◽  
Vol 76 (3) ◽  
pp. 556-569 ◽  
Author(s):  
E. Nieschlag ◽  
K. H. Usadel ◽  
H. K. Kley ◽  
U. Schwedes ◽  
K. Schöffling ◽  
...  
Keyword(s):  
Feedback Control ◽  
Leydig Cells ◽  
Positive Response ◽  
Active Immunization ◽  
Biologically Active ◽  
Control Group ◽  
Control Mechanisms ◽  
New Approach ◽  
Biological Neutralization ◽  
Group Serum

ABSTRACT A new method for the investigation of hypothalamo-pituitary-gonadal and adrenal feedback control mechanisms based on the biological neutralization of gonadal and adrenal steroids by active immunization is proposed. The regulatory influence of a given steroid in the feedback control is proved when reduction of the free, biologically active fraction of this steroid caused by antibody binding induces a positive response of the pituitary, thus effecting gonadal or adrenal hypertrophy and hyperfunction. The advantages and limitations of the new model are demonstrated by the effects of active immunization of rabbits with cortisol (F), aldosterone (Aldo), dehydroepiandrosterone (DHA), androstenedione (Δ4-A), testosterone (T), 5α-dihydrotestosterone (5α-DHT), 5β-DHT and oestradiol (E2). In the immunized animals and in a control group serum concentrations of total corticosteroids (TC), DHA, T, Δ4-A, E1, E2, LH and FSH, the percentage of binding of steroids in serum and the specificity of the antisera are determined. The testes are evaluated by histometry and the nuclear volume of the adrenocortical and Leydig cells is measured.

scholarly journals Retention behaviour of acyclic polyfunctional D-arabinose derivatives

2002 ◽  
pp. 35-44 ◽  
Author(s):  
Ljiljana Kolarov ◽  
Eva Loncar ◽  
Radomir Malbasa
Keyword(s):  
Mobile Phase ◽  
Volume Fraction ◽  
Retention Mechanism ◽  
Biologically Active ◽  
Polar Component ◽  
Chiral Molecules ◽  
Retention Behaviour ◽  
Polar Components ◽  
Solute Retention ◽  
Mobile Phases

It is well known that some of biologically active compounds are chiral molecules. Natural monosaccarides are applicable as chiral precursors. D-arabinose is an appropriate chiral precursor in the synthesis of very important biomolecules such as biotin and its analogues and feromon )-exobrevicomin. Acyclic poly functional D- arabinose derivatives are intermediates in the synthesis of the former biomolecules. This paper deals with the retention behaviour and retention mechanism of acyclic poly functional D-arabinose derivatives. The tested compounds have been chromato graphed on silica gel thin layer using binary organic mobile phases with a different polarity. With increasing polarity of the eluent polar components the solute retention is decreasing. The linear relationship is obtained between the values of retention constant, RM' and the logarithm of the mobile phase polar component volume fraction for all solutes tested and eluents used.

A new approach for the synthesis of biologically active chromene compounds using a photo catalyst TiO2-Ag

2021 ◽  
pp. 1-21
Author(s):  
George Kupar Kharmawlong ◽  
Ridaphun Nongrum ◽  
John Elisa Kumar ◽  
Bhusan Chhetri ◽  
Arun Kumar Yadav ◽  
...  
Keyword(s):  
Biologically Active ◽  
New Approach ◽  
Photo Catalyst

scholarly journals Decorative Magnolia Plants: A Comparison of the Content of Their Biologically Active Components Showing Antimicrobial Effects

Plants ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 879
Author(s):  
Petra Lovecká ◽  
Alžběta Svobodová ◽  
Anna Macůrková ◽  
Blanka Vrchotová ◽  
Kateřina Demnerová ◽  
...  
Keyword(s):  
High Performance ◽  
Leaf Extract ◽  
Reversed Phase ◽  
Hybrid Plant ◽  
Biologically Active ◽  
Medicinal Products ◽  
Active Components ◽  
Rp Hplc ◽  
Hybrid Plants ◽  
Hplc Fractionation

Magnolia plants are used both as food supplements and as cosmetic and medicinal products. The objectives of this work consisted of preparing extracts from leaves and flowers of eight Magnolia plants, and of determining concentrations of magnolol (1 to 100 mg·g−1), honokiol (0.11 to 250 mg·g−1), and obovatol (0.09 to 650 mg·g−1), typical neolignans for the genus Magnolia, in extracts made by using a methanol/water (80/20) mixture. The tested Magnolia plants, over sixty years old, were obtained from Průhonický Park (Prague area, Czech Republic): M. tripetala MTR 1531, M. obovata MOB 1511, and six hybrid plants Magnolia × pruhoniciana, results of a crossbreeding of M. tripetala MTR 1531 with M. obovata MOB 1511. The identification of neolignans was performed by HRMS after a reversed-phase high-performance liquid chromatography (RP-HPLC) fractionation of an extract from M. tripetala MTR 1531. The highest concentrations of neolignans were found in the flowers, most often in their reproductive parts, and obovatol was the most abundant in every tested plant. The highest concentrations of neolignans were detected in parent plants, and lower concentrations in hybrid magnolias. Flower extracts from the parent plants M. tripetala MTR 1531 and M. obovata MOB 1511, flower extracts from the hybrid plants Magnolia × pruhoniciana MPR 0271, MPR 0151, and MPR 1531, and leaf extract from the hybrid plant Magnolia × pruhoniciana MPR 0271 inhibited growth of Staphylococcus aureus.

HPLC-Diode Array Detector Fingerprints of Various Mentha Species

2014 ◽  
Vol 97 (5) ◽  
pp. 1268-1273 ◽  
Author(s):  
Mirosław A Hawrył
Keyword(s):  
Plant Material ◽  
Computer Software ◽  
Gradient Elution ◽  
Array Detector ◽  
Diode Array ◽  
Retention Data ◽  
Diode Array Detector ◽  
Mobile Phases

Abstract Gradient elution HPLC was applied to develop fingerprints of 12 extracts obtained from selected mint species. The gradient was optimized by use of Merck ChromSword computer software on the basis of retention data of some standard compounds occurring in the investigated plant material. Two column types (RP18 and pentafluorophenyl) and two mobile phases (methanol–water and acetonitrile–water) were used during the experiments. Fingerprints of all extracts were generated, and on the basis of the fingerprints identification of the mints was possible.

scholarly journals Exosome: A New Player in Translational Nanomedicine

2020 ◽  
Vol 9 (8) ◽  
pp. 2380 ◽  
Author(s):  
Houssam Aheget ◽  
María Tristán-Manzano ◽  
Loubna Mazini ◽  
Marina Cortijo-Gutierrez ◽  
Pablo Galindo-Moreno ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Cell Types ◽  
Structural Features ◽  
Biologically Active ◽  
Biological Processes ◽  
New Approach ◽  
Current State ◽  
Exosome Biogenesis ◽  
Production Techniques

Summary: Exosomes are extracellular vesicles released by the vast majority of cell types both in vivo and ex vivo, upon the fusion of multivesicular bodies (MVBs) with the cellular plasma membrane. Two main functions have been attributed to exosomes: their capacity to transport proteins, lipids and nucleic acids between cells and organs, as well as their potential to act as natural intercellular communicators in normal biological processes and in pathologies. From a clinical perspective, the majority of applications use exosomes as biomarkers of disease. A new approach uses exosomes as biologically active carriers to provide a platform for the enhanced delivery of cargo in vivo. One of the major limitations in developing exosome-based therapies is the difficulty of producing sufficient amounts of safe and efficient exosomes. The identification of potential proteins involved in exosome biogenesis is expected to directly cause a deliberate increase in exosome production. In this review, we summarize the current state of knowledge regarding exosomes, with particular emphasis on their structural features, biosynthesis pathways, production techniques and potential clinical applications.

ChemInform Abstract: Synthesis and RP HPLC Studies of Biologically Active Semicarbazides and Their Cyclic Analogues 1,2,4-Triazol-3-ones.

ChemInform ◽  
2012 ◽  
Vol 43 (30) ◽  
pp. no-no
Author(s):  
Monika Pitucha ◽  
Joanna Matysiak ◽  
Bogdan Senczyna
Keyword(s):  
Biologically Active ◽  
Rp Hplc
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