Search results for "liquid"
showing 10 items of 4351 documents
Evaluation of the pH effect of formulations on the skin permeability of drugs by biopartitioning micellar chromatography☆
2004
Dermal absorption of chemicals is an area of increasing interest for the pharmaceutical and cosmetic industries, as well as in dermal exposure and risk assessment processes. Biopartitioning micellar chromatography (BMC) is a mode of reversed phase micellar chromatography that has proved to be useful in the description and prediction of several pharmacological properties of xenobiotics including oral drug absorption, ocular and skin drug permeability. The present paper deals with the application of biopartitionig micellar chromatography to evaluate the pH effect on the skin permeability of twelve non-steroidal anti-inflammatory drugs and lidocaine. For this purpose the BMC retention of the w…
Silver ion chromatography and gas chromatography-mass spectrometry in the structural analysis of cyclic dienoic acids formed in frying oils
1995
The nature of the cyclic monoenoic fatty acids formed from linoleic acid in sunflower oil heated to 275°C has been determined by gas chromatography-mass spectrometry of the picolinyl ester derivatives, before and after hydrogenation and deuteration, and following simplification by silver ion high-performance liquid chromatography. In addition, they were examined by gas chromatography-Fourier transform infrared spectroscopy. Cyclopentene fatty acids (50% of the total monoenes) were formed from C-8 to C-12 and C-10 to C-14 of the original chain in equal amounts with unique stereochemistry. In some isomers the double bond appeared to remain in its original position, and in others it migrated t…
Drift Time Measurement in the ATLAS Liquid Argon Electromagnetic Calorimeter using Cosmic Muons
2010
The ionization signals in the liquid argon of the ATLAS electromagnetic calorimeter are studied in detail using cosmic muons. In particular, the drift time of the ionization electrons is measured and used to assess the intrinsic uniformity of the calorimeter gaps and estimate its impact on the constant term of the energy resolution. The drift times of electrons in the cells of the second layer of the calorimeter are uniform at the level of 1.3% in the barrel and 2.8% in the endcaps. This leads to an estimated contribution to the constant term of (0.29-0.04+0.05)% in the barrel and (0.54-0.04+0.06)% in the endcaps. The same data are used to measure the drift velocity of ionization electrons …
Effect of cultivation techniques on the hydrodynamic and mechanical behaviour of the "Lauragais-terreforts"
1993
The effect of various seed bed preparations on hydrodynamic and mechanical parameters was studied experimentally by simulated rainfall on clayeyloamy soils Lauragais, which had developed on chalky molasse on a slope greater than 12 %. The level of soaked up rain ("pluie d'imbibition", Pi) is closely connected to the inital degree of saturation of the soil ; it varies from 10 to 24 mm when the soil is humid and increases when the soil is dry (14 to 47 mm). But when the soil surface is crusted the Pi is less and seems to be no longer controlled by the degree of water in the soil. Treatments with fine structural elements show the fewest possibilities of infiltration during the soaking up stage…
Simulated raindrop's characteristic measurements. A new approach of image processing tested under laboratory rainfall simulation
2018
Abstract The size of the drops determines soil erosion and runoff rates, and then the fate of ecosystems. Various raindrop measurement techniques and tools have been developed to determine natural and simulated raindrop size distributions and mean drop size. There is a need to improve the procedure to determine the raindrop properties, and this is why we develop a new technique to analyze drop size distribution and fall velocity. For this purpose a rainfall simulator with two oscillating Veejet 80100 nozzles in laboratory condition, and high speed imaging technique and edge detection approach in image processing was applied to identify and measure drop size and calculate drop velocity. The …
Loading profile of topotecan into polyvinyl alcohol microspheres (DC Bead™) over a 7-day period
2011
Purpose: DC Bead™ is successfully used for chemoembolization of various liver cancers. The purpose of this study was todetermine the loading capacity of the semi-synthetic topoisomerase-1 inhibitor topotecan into the DC Bead™ microspheres under static or agitated conditions and to assess the physicochemical stability over a period of 7 days. Methods: Commercially available topotecan hydrochloride powder (Hycamtin®) was reconstituted with water for injection to yield a nominal concentration of 1 mg/mL topotecan. Polyvinyl alcohol (PVA)-based microspheres (DC Bead™, 300–500 µm, 2 mL/vial) were mixed with 4 mL of the reconstituted topotecan solution. Vials were stored light protected at room …
Loading, release and stability of epirubicin-loaded drug-eluting beads.
2015
Purpose The aim of this study was to determine the loading efficiency, physico-chemical stability and release of epirubicin-loaded DC Bead™ (Biocompatibles UK Ltd, a BTG International group company) (bead size 70–150 µm (=DC Bead M1™) and 100–300 µm) after loading with epirubicin solution (2 mg/ml) or reconstituted powder formulation (25 mg/ml) and controlled storage. Methods DC Bead™ were loaded with 76 mg epirubicin solution (Epimedac™, Medac GmbH) or 75 mg epirubicin powder formulation (Farmorubicin™, Pharmacia Pfizer GmbH) per 2 ml of beads. Drug loading efficiency and stability were determined by measuring the epirubicin concentration in the excess solution after predetermined interval…
Stability of tacrolimus ophthalmic solution
2017
Purpose The stability of 0.3-mg/mL tacrolimus ophthalmic solution at different storage temperatures was studied. Methods A sterile ophthalmic solution of 0.3 mg/mL tacrolimus was prepared in triplicate under aseptic conditions by diluting tacrolimus in eye drops. Three aliquots of this solution were transferred into polypropylene bottles and stored at 25, 2–8, or −15 to −25 °C. Samples were collected immediately after preparation and at selected time points and assayed in triplicate using high-performance liquid chromatography (HPLC). Samples were also visually examined for macroscopic changes. The 0.3-mg/mL tacrolimus solution was also exposed to acidic treatment and heat to force its degr…
Biopartitioning micellar chromatography: an in vitro technique for predicting human drug absorption.
2001
The main oral drug absorption barriers are fluid cell membranes and generally drugs are absorbed by a passive diffusion mechanism. Biopartitioning micellar chromatography (BMC) is a mode of micellar liquid chromatography that uses micellar mobile phases of Brij35 under adequate experimental conditions and can be useful to mimic the drug partitioning process in biological systems. In this paper the usefulness of BMC for predicting oral drug absorption in humans is demonstrated. A hyperbolic model has been obtained using the retention data of a heterogeneous set of 74 compounds, which shows predictive ability for drugs absorbed by passive diffusion. The model obtained in BMC is compared with …
Duloxetine serum concentrations and clinical effects. Data from a therapeutic drug monitoring (TDM) survey.
2009
INTRODUCTION The aim of this study was to relate drug concentrations in serum and clinical effects in patients treated with the new antidepressant duloxetine. METHODS Data were obtained from a newly established therapeutic drug monitoring (TDM) survey. Duloxetine was measured using HPLC with UV detection and clinical effects by the clinical global impressions (CGI) scale for improvement. RESULTS The study included 103 depressed inpatients (69% female). Patients under duloxetine monotherapy who were very much improved according to CGI had significantly (p<0.05) higher serum levels than patients with moderate, minimal or lacking improvement (mean+/-SD and range, 93+/-53 ng/mL and 30-182 ng/mL…