Search results for "Drug Stability"
showing 10 items of 113 documents
An investigation of the stability of free and glucuronidated 11-nor-delta9-tetrahydrocannabinol-9-carboxylic acid in authentic urine samples.
2004
Preanalytical stability of a drug and its major metabolites is an important consideration in pharmacokinetic studies or whenever the analyte pattern is used to estimate drug habits. Firstly, the stability of free and glucuronidated 11-nor-delta9-tetrahydrocannabinol-9-carboxylic acid (THCCOOH, THCCOOglu) in authentic urine samples was investigated. Random urine samples of cannabis users (n = 38) were stored at -20, 4, and 20 degrees C up to 15 days and up to 5 days at 40 degrees C, and alterations of the analyte pattern during storage were followed by liquid chromatography-tandem mass spectrometry. Secondly, the influence of pH (range 5.0-8.0) on the stability of the analytes was studied us…
Delivery of liquorice extract by liposomes and hyalurosomes to protect the skin against oxidative stress injuries.
2015
Liquorice extract, obtained by percolation in ethanol of Glycyrrhiza glabra L. roots, was incorporated in liposomes and hyalurosomes, new phospholipid-sodium hyaluronate vesicles, and their protective effect against oxidative stress skin damages was probed. As a comparison, raw glycyrrhizin was also tested. All the vesicles were small in size (≤ 100 nm), with a highly negative zeta potential ensuring long-term stability, and able to incorporate a high amount of the extract. In vitro tests showed that the liquorice extract loaded in vesicles was able to scavenge DPPH free radical (80% inhibition) and to protect 3T3 fibroblasts against H2O2-induced oxidative stress, restoring the normal condi…
In vitro digestion of betalainic foods. Stability and bioaccessibility of betaxanthins and betacyanins and antioxidative potential of food digesta.
2008
Betalains are considered to be bioactive dietary phytochemicals. The stability of betacyanins and betaxanthins from either fresh foods or manufactured products of cactus pear fruit ( Opuntia ficus indica L. Mill. cv. Gialla and Rossa) and red beet ( Beta vulgaris L. ssp. vulgaris) was assessed in a simulated oral, gastric, and small intestinal digestion and compared with the digestive stability of purified pigments. A minor loss of indicaxanthin, at the gastric-like environment only, and a decrease of vulgaxanthin I through all digestion steps were observed, which was not affected by food matrix. In contrast, food matrix prevented decay of betanin and isobetanin at the gastric-like environm…
Controlling protein interactions in blood for effective liver immunosuppressive therapy by silica nanocapsules
2020
Immunosuppression with glucocorticoids is a common treatment for autoimmune liver diseases and after liver transplant, which is however associated with severe side-effects. Targeted delivery of glucocorticoids to inflammatory cells, e.g. liver macrophages and Kupffer cells, is a promising approach for minimizing side effects. Herein, we prepare core–shell silica nanocapsules (SiO2 NCs) via a sol–gel process confined in nanodroplets for targeted delivery of dexamethasone (DXM) for liver immunosuppressive therapy. DXM with concentrations up to 100 mg mL−1 in olive oil are encapsulated while encapsulation efficiency remains over 95% after 15 days. Internalization of NCs by non-parenchymal muri…
Labeling and preliminary in vivo assessment of niobium-labeled radioactive species: A proof-of-concept study.
2016
Abstract The application of radionuclide-labeled biomolecules such as monoclonal antibodies or antibody fragments for imaging purposes is called immunoscintigraphy . More specifically, when the nuclides used are positron emitters, such as zirconium-89, the technique is referred to as immuno-PET . Currently, there is an urgent need for radionuclides with a half-life which correlates well with the biological kinetics of the biomolecules under question and which can be attached to the proteins by robust labeling chemistry. 90 Nb is a promising candidate for in vivo immuno-PET , due its half-life of 14.6h and low β + energy of E mean =0.35MeV per decay. 95 Nb on the other hand, is a convenient …
Desferrioxamine as an appropriate chelator for 90Nb: Comparison of its complexation properties for M-Df-Octreotide (M=Nb, Fe, Ga, Zr)
2014
The niobium-90 radioisotope ((90)Nb) holds considerable promise for use in immuno-PET, due to its decay parameters (t½ = 14.6h, positron yield=53%, Eß(+)(mean) = 0.35 MeV and Eß(+)(max) = 1.5 MeV). In particular, (90)Nb appears well suited to detect in vivo the pharmacokinetics of large targeting vectors (50-150 kDa). In order to be useful for immuno-PET chelators are required to both stabilize the radionuclide in terms of coordination chemistry and to facilitate the covalent attachment to the targeting vector. Different chelators were evaluated for this purpose in terms of radiolabelling efficiency and stability of the radiolabelled Nb(V) complex and in order to determine the most suitable…
[Post-translational regulation of N-glycosylated proteins expression in human intestinal cells in culture].
1991
International audience; HT-29 cells derived from a human colonic adenocarcinoma, can express a typical intestinal differentiation. Undifferentiated HT-29 cells accumulate N-linked glycoproteins substituted with unprocessed carbohydrate chains before to degrade them. Conversely, carbohydrate chains of N-linked glycoproteins are classically processed in differentiated HT-29 cells. The instability of N-linked glycoproteins in undifferentiated HT-29 cells is due to their rapid delivery from the endoplasmic reticulum to a compartment with lysosomal characteristics. This catabolitic pathway involves a bypass of the Golgi apparatus.
Nanocarriers for antioxidant resveratrol: formulation approach, vesicle self-assembly and stability evaluation.
2013
In this work we studied various nanoformulations of resveratrol in phospholipid vesicles. Conventional phophatidylcholine liposomes were prepared and characterized in parallel with PEVs (Penetration Enhancer-containing Vesicles) obtained by adding one of eight selected amphiphilic penetration enhancers (PEs; 0.2% w/v; HLB range 1-16) to the composition. All vesicles were around 100 nm, negatively charged (∼-30 mV) and able to incorporate resveratrol in good yields (>74%). The structure and the lamellar self-organization of the vesicles were investigated by Transmission Electron Microscopy (TEM) and Small and Wide Angle X-ray Scattering (SWAXS). These analyses showed that the lamellarity of …
Mechanistic and kinetic insight into spontaneous cocrystallisation of isoniazid and benzoic acid
2015
Solid-state cocrystallisation is of contemporary interest, because it offers an easy and efficient way to produce cocrystals, which are recognized as prospective pharmaceutical materials. Research explaining solid-state cocrystallisation mechanisms is important, but still too scarce to give a broad understanding of factors governing and limiting these reactions. Here we report an investigation of the mechanism and kinetics of isoniazid cocrystallisation with benzoic acid. This reaction is spontaneous; however its rate is greatly influenced by environmental conditions (humidity and temperature) and pre-treatment (milling) of the sample. The acceleration of cocrystallisation in the presence o…
Role of Seroalbumin in the Cytotoxicity of cis-Dichloro Pt(II) Complexes with (N^N)-Donor Ligands Bearing Functionalized Tails
2018
Given the potent anticancer properties of cisdiamminedichloroplatinum( II) and knowing its mode of action, we synthesized four new cis-[PtCl2(N^N)] organoplatinum complexes, two with N-substituted pbi ligands (pbiR = 1-R-2-(2-pyridyl)benzimidazole) (namely, 1 and 2) and two more with 4,4′-disubstituted bpy ligands (bpy = 2,2′-bipyridine) (namely, 3 and 4). We explored their cytotoxicity and ability to bind to deoxyguanosine monophosphate (dGMP), DNA, and albumin models. By 1H NMR and UV−vis spectroscopies, circular dichroism, agarose gel electrophoresis, differential scanning calorimetry measurements, and density functional theory calculations, we verified that only 3 can form aquacomplex s…