Search results for "Chromatography"

Partial purification and characterization of an NAD-dependent 3 beta-hydroxysteroid dehydrogenase from Clostridium innocuum

1989

In nine strains of Clostridium innocuum, 3 beta-hydroxysteroid-dehydrogenating activities were detected. 3 beta, 7 alpha, 12 alpha-Trihydroxy- and 3 beta-hydroxy-12-keto-5 beta-cholanoic acids were identified as reduction products of the respective 3-keto bile acids by gas-liquid chromatography and gas-liquid chromatography-mass spectrometry. One strain was shown to contain a NAD-dependent 3 beta-hydroxysteroid dehydrogenase. Enzyme production was constitutive in the absence of added bile acids. The specific enzyme activity was significantly reduced by growth medium supplementation with 3-keto bile acids, with trisubstituted acids being more effective than disubstituted ones. A pH optimum o…

Development and validation of an analytical assay for electrochemical detection and quantification of protein‐bound 3‐nitrotyrosine in biological sam…

2020

Co-Loading of Ascorbic Acid and Tocopherol in Eudragit-Nutriosomes to Counteract Intestinal Oxidative Stress

2019

The present study aimed at developing a new vesicular formulation capable of promoting the protective effect of ascorbic acid and tocopherol against intestinal oxidative stress damage, and their efficacy in intestinal wound healing upon oral administration. A pH-dependent copolymer (Eudragit&reg

Synchronizing the release rates of salicylate and indomethacin from degradable chitosan hydrogel and its optimization by definitive screening design.

2018

Abstract Three types of ionically crosslinked (with citric acid) chitosan discs were loaded with the highly water- soluble drug, sodium salicylate (SS) and the poorly water-soluble drug, indomethacin (Ind). In separate experiments the hydrated discs were immersed in a de-crosslinking solution comprising of different concentrations of calcium chloride, which induced a controlled erosion of the discs, a process which was optimized to synchronize the release rates of the two drugs over a predetermined period of time. The optimization was accomplished by manipulating six factors: chitosan MW, its amount in the formulation, the concentration of the crosslinker agent, the concentration of the de-…

Glycerosomes: Use of hydrogenated soy phosphatidylcholine mixture and its effect on vesicle features and diclofenac skin penetration.

2016

In this work, diclofenac was encapsulated, as sodium salt, in glycerosomes containing 10, 20 or 30% of glycerol in the water phase with the aim to ameliorate its topical efficacy. Taking into account previous findings, glycerosome formulation was modified, in terms of economic suitability, using a cheap and commercially available mixture of hydrogenated soy phosphatidylcholine (P90H). P90H glycerosomes were spherical and multilamellar; photon correlation spectroscopy showed that obtained vesicles were ∼131nm, slightly larger and more polydispersed than those made with dipalmitoylphosphatidylcholine (DPPC) but, surprisingly, they were able to ameliorate the local delivery of diclofenac, whic…

Solid microcrystalline dispersion films as a new strategy to improve the dissolution rate of poorly water soluble drugs: A case study using olanzapine

2016

In this study, we evaluate the dissolution rate enhancement of solid microcrystalline dispersion (SMD) films of olanzapine (OLZ) formulated with four water-soluble polymers namely poly(N-vinylpyrrolidone) (PVP), poloxamer 188 (P188), poloxamer 407 (P407) and Soluplus(®) (SLP). Prepared formulations were characterised to determine particle size, morphology, hydrogen bonding interactions, thermal characteristics as well as in vitro dissolution studies conducted under sink conditions (pH 6.8). Particle size of OLZ in all formulations ranged between 42 and 58μm. Attenuated Total Reflectance Fourier Transform Infrared spectroscopy (ATR-FTIR), Differential Scanning Calorimetry (DSC) and Hot-Stage…

COMBINATION OF ARGAN OIL AND PHOSPHOLIPIDS FOR THE DEVELOPMENT OF AN EFFECTIVE LIPOSOME-LIKE FORMULATION ABLE TO IMPROVE SKIN HYDRATION AND ALLANTOIN…

2016

Allantoin is traditionally employed in the treatment of skin ulcers and hypertrophic scars. In the present work, to improve its local deposition in the skin and deeper tissues, allantoin was incorporated in conventional liposomes and in new argan oil enriched liposomes. In both cases, obtained vesicles were unilamellar, as confirmed by cryo-TEM observation, but the addition of argan oil allowed a slight increase of the mean diameter (∼130nm versus ∼85nm). The formulations, especially those containing argan oil, favoured the allantoin accumulation in the skin, in particular in the dermis (∼8.7μg/cm(2)), and its permeation through the skin (∼33μg/cm(2)). The performances of vesicles as skin d…

Formation of 3-methyl-1,2,3-butanetricarboxylic acid via gas phase oxidation of pinonic acid – a mass spectrometric study of SOA aging

2012

Abstract. This paper presents the results of mass spectrometric investigations of the OH-initiated oxidative aging of α-pinene SOA under simulated tropospheric conditions at the large aerosol chamber facility AIDA, Karlsruhe Institute of Technology. In particular, the OH-initiated oxidation of pure pinic and pinonic acid, two well-known oxidation products of α-pinene, was investigated. Two complementary analytical techniques were used, on-line atmospheric pressure chemical ionization/mass spectrometry (APCI/MS) and filter sampling followed by liquid chromatography/mass spectrometry (LC/ESI-MS). The results show that 3-methyl-1,2,3-butanetricarboxylic acid (MBTCA), a very low volatile α-pine…

Thermomineral waters of Greece: geochemical characterization

2020

Early ROS-mediated DNA damage and oxidative stress biomarkers in Monoclonal B Lymphocytosis

2012

Monoclonal B Lymphocytosis (MBL) is defined as asymptomatic monoclonal B-cell expansion characterised by a CLL-phenotype, but with less than 5 x 10(9)/I circulating cells. Reactive oxygen species (ROS)-mediated cell damage plays a critical role in the initiation of carcinogenesis as well as in malignant transformation. The goal of this study was to perform an analysis of the oxidative stress statuses of patients affected by MBL and chronic lymphocytic leukaemia (CLL). We examined peripheral blood and urine specimens from 29 patients with MBL, 55 with CLL and 31 healthy subjects. There was a significant increase in the occurrence of the mutagenic base 8-oxo-2'-deoxiguanosine (8-oxo-dG) in th…