Search results for "glycolic acid"

Laparoscopic Repair of Boundary Incisional Hernia in a Kidney Transplant Patient: A Safe Tacks-Fibrin Glue Combined Mesh Fixation Technique.

2018

Abstract Background Incisional hernia in renal transplant patients is a complication that negatively affects the global outcome of transplant and quality of life. The repair of this condition was classically made by open repair with mesh. Increasing evidence suggests that laparoscopic repair could be advocated as the technique of choice in these patients with optimal results. However, the fixation of mesh should be performed by a mixed combination of fibrin sealant (lateral margin of wall defect) and tacks (medial margin). The tacks fixation of the mesh along the lateral margin of the wall defect, close to the graft, is generally difficult for the small size of the remaining aponeurotic pla…

Process parameters of microsphere preparation based on propylene carbonate emulsion-precursors.

2020

This study aimed for a detailed understanding of the impact of different process parameters involved during celecoxib-loaded microsphere preparation based on propylene carbonate emulsion-precursors.Microspheres were prepared by a modified emulsification-solvent extraction method. Performed investigations included polymer solubility and viscosity, microsphere size, morphology and stability, propylene carbonate content as well as celecoxib solid state, content and release.Rough-walled round microspheres with sizes between 21 µm and 122 µm and an internal sponge-like structure filled with residual propylene carbonate (content between 1.9 ± 0.1% and 6.7 ± 0.5% w/w) were obtained. Encapsulation …

High vibrational overtone excitation‐induced conformational isomerization of glycolic acid in solid argon matrix

2018

Emulsion-based synthesis of PLGA-microspheres for the in vitro expansion of porcine chondrocytes.

2007

Abstract The in vitro cell expansion of autologous chondrocytes is of high interest in regenerative medicine since these cells can be used to treat joint cartilage defects. In order to preserve chondrocyte phenotype, while optimizing adhesion on microspheres, several processing parameters for the microsphere synthesis were varied. In this study three different polylactide-co-glycolides were used with differing lactide–glycolide ratios (85:15 and 50:50) and differing inherent viscosities. An emulsion route was established, where the polymer was dissolved in chloroform and then injected into a stirred polyvinyl alcohol–water solution at different polymer concentrations and different stirring …

Dexamethasone dipropionate loaded nanoparticles of α-elastin-g-PLGA for potential treatment of restenosis.

2013

A graft copolymer of α-elastin with poly(lactic-co-glycolic) acid (PLGA) has been synthesized and successfully employed to produce nanoparticles. Exploiting the known biological activity of α-elastin to promote the maintenance of smooth muscle cells (SMCs) contractile phenotype and the antiproliferative effect of glucocorticoids, the aim of this research was to produce drug-loaded nanoparticles suitable for potential treatment of restenosis. In particular, nanoparticles of α-elastin-g-PLGA with a mean size of 200 nm have been produced and loaded with dexamethasone dipropionate (10% w/w), chosen as a model drug that inhibits proliferation of vascular SMCs. These nanoparticles are able to pro…

Strukturuntersuchung von polyestern durch direkten abbau im massenspektrometer, 4. Polyester und copolyester der milchsäure und glykolsäure

1978

Polyesters and copolyesters of 2-hydroxyacetic acid (glycolic acid) and 2-hydroxypropionic acid (lactic acid) were investigated by direct pyrolysis in the ion source of a mass spectrometer. Thermal degradation of these polyesters and copolyesters at 10−6 mbar yields cyclic oligomers which are further degraded by an electron impact induced mechanism by elimination of formaldehyde or acetaldehyde and CO2 to give characteristic series of linear ions. In the pyrolysis mass spectrum of a copolyester (mole ratio of monomeric units ≈1:1) intact sequences up to 8 monomeric units can be observed.

Uptake of polymeric nanoparticles in a human induced pluripotent stem cell-based blood-brain barrier model: Impact of size, material, and protein cor…

2021

The blood–brain barrier (BBB) maintains the homeostasis of the central nervous system, which is one of the reasons for the treatments of brain disorders being challenging in nature. Nanoparticles (NPs) have been seen as potential drug delivery systems to the brain overcoming the tight barrier of endothelial cells. Using a BBB model system based on human induced pluripotent stem cells (iPSCs), the impact of polymeric nanoparticles has been studied in relation to nanoparticle size, material, and protein corona. PLGA [poly(lactic-co-glycolic acid)] and PLLA [poly(d,l-lactide)] nanoparticles stabilized with Tween® 80 were synthesized (50 and 100 nm). iPSCs were differentiated into human brain m…

GHB related acids are useful in routine casework of suspected GHB intoxication cases

2021

Abstract GHB related acids (3,4-dihydroxy butyric acid, 2,4-dihydroxy butyric acid and glycolic acid) are produced through oxidative GHB metabolism. These analytes could be potential biomarkers to ensure the diagnosis of a GHB intoxication and even prolong the detection window. Within this study, forensic routine cases were measured to consider the potential of additional gas chromatographic mass spectrometric analysis on these acids. 17 GHB positive real cases (10 serum samples and 7 urine samples) and 40 cases with suspicion of drugging in DFC cases and negative GHB results (21 serum samples and 19 urine samples) were evaluated. Increased GHB related acid concentrations were detected in a…

2019

Molecular complexes between glycolic acid and nitrogen were studied in a low-temperature argon matrix with FTIR spectroscopy, and supported by MP2 and BLYPD3 calculations. The calculations indicate 11 and 10 stable complex structures at the MP2 and BLYPD3 levels of theories, respectively. However, only one hydrogen-bonded complex structure involving the most stable SSC conformer of glycolic acid was found experimentally, where the nitrogen molecule is bound with the carboxylic OH group of the SSC conformer. The complex shows a rich site structure variation upon deposition of the matrix in different temperatures and upon annealing experiments, which provide interesting prospects for site-sel…

Chromatographic Determination of Thiols After Pre‐column Derivatization witho‐Phthalaldehyde and Isoleucine

2004

Abstract The reaction of primary amines with excess o‐phthalaldehyde (OPA) and thiol yields unique isoindole derivatives that are readily separated by reversed‐phase liquid chromatography. In a previous work, a spectrophotometric procedure was proposed for the assay of N‐acetylcysteine by derivatization with OPA and isoleucine at pH 9.5, with satisfactory results. The chromatographic determination of this and other low molecular‐weight thiols, after isoindole formation with isoleucine, using mobile phases of acetonitrile–water at pH 3 and spectrophotometric detection, is now examined. From the assayed thiols (thioglycolic acid, 3‐mercaptopropionic acid, tiopronin, N‐acetylcysteine, N‐acetyl…