Search results for "DELIVERY"
showing 10 items of 1271 documents
Phosphonylation Controls the Protein Corona of Multifunctional Polyglycerol-Modified Nanocarriers.
2018
Nanocarriers are a platform for modern drug delivery. In contact with blood, proteins adsorb to nanocarriers, altering their behavior in vivo. To reduce unspecific protein adsorption and unspecific cellular uptake, nanocarriers are modified with hydrophilic polymers like poly(ethylene glycol) (PEG). However, with PEG the attachment of further functional structures such as targeting units is limited. A method to introduce multifunctionality via polyglycerol (PG) while maintaining the hydrophilicity of PEG is introduced. Different amounts of negatively charged phosphonate groups (up to 29 mol%) are attached to the multifunctional PGs (Mn 2-4 kg mol-1 , Ð < 1.36) by post-modification. PGs are …
Orthogonal Click Conjugation to the Liposomal Surface Reveals the Stability of the Lipid Anchorage as Crucial for Targeting
2016
Synthetic access to multiple surface decorations are a bottleneck in the development of liposomes for receptor mediated targeting. This opens a complex multiparameter space, exploration of which is severely limited in terms of sample numbers and turnaround times. Here, we unlock this technological barrier by a combination of a milligram-scale liposome formulation using dual centrifugation and orthogonal click chemistry on the liposomal surface. Application of these techniques to conceptually new amphiphilic compounds, which feature norbornene and alkyne groups at the apex of sterically stabilizing, hyperbranched polyglycerol moieties, revealed a particular influence of the membrane anchor o…
New biodegradable hydrogels based on a photocrosslinkable modified polyaspartamide: synthesis and characterization
1999
Abstract α,β-Poly( N -2-hydroxyethyl)- dl -aspartamide (PHEA), a synthetic water-soluble biocompatible polymer, was derivatized with glycidyl methacrylate (GMA), in order to introduce in its structure chemical residues having double bonds and ester groups. The obtained copolymer (PHG) contained 29 mol% of GMA residues. PHG aqueous solutions at various concentrations ranging from 30 to 70 mg/ml were exposed to a source of UV rays at λ 254 nm in the presence or in the absence of N , N ′-methylenebisacrylamide (BIS); the formation of compact gel phases was observed beginning from 50 mg/ml. The obtained networks were characterized by FT-IR spectrophotometry and swelling measurements which evide…
Biodegradable hydrogels obtained by photocrosslinking of dextran and polyaspartamide derivatives
2003
The functionalization of dextran with glycidyl methacrylate (GMA) leads to the formation of a derivative that generates hydrogels for irradiation at 365nm. The effects of various polymer concentrations and irradiation times on the yield and the properties of the obtained hydrogels are reported. The networks have been characterized by FT-IR spectra, dimensional analysis and swelling measurements carried out at different pH values. In vitro studies suggest that all samples undergo a partial chemical hydrolysis, whereas the incubation with dextranases causes a total degradation whose rate depends on the degree of crosslinking. In addition, aqueous solutions of functionalized dextran have been …
DRUG DELIVERY FROM MUCOADHESIVE DISKS BASED ON A PHOTO-CROSS-LINKABLE POLYASPARTAMIDE DERIVATIVE
2005
Disks for local delivery of amoxicillin to the buccal or gastric cavity were prepared using as starting polymer a polyaspartamide derivative. In particular, α,β-poly(N-2-hydroxyethyl)-DL-aspartamide (PHEA) was derivatized with glycidyl methacrylate (GMA) in order to synthesize PHG, a photo-cross-linkable and biodegradable polymer that gives rise to the formation of a chemical hydrogel (PHG-UV) by UV irradiation. This hydrogel was shaped as disks whose mucoadhesive properties have been confirmed by swelling measurements in phosphate buffer/citric acid solution at pH 7.0 in the presence of various concentrations of mucin. Swelling ability of PHG-UV disks was also evaluated in simulated saliva…
The baculovirus display technology--an evolving instrument for molecular screening and drug delivery.
2008
High throughput screening is a core technology in drug discovery. During the past decade, several strategies have been developed to screen (poly)peptide libraries for diverse applications including disease diagnosis and profiling, imaging, as well as therapy. The recently established baculovirus display vector system (BDVS) represents a eukaryotic screening platform that combines the positive attributes of both cell and virus-based display approaches, allowing presentation of complex polypeptides on cellular and viral surfaces. Compared to microbial display systems, the BDVS has the advantage of correct protein folding and post-translational modifications similar to those in mammals, facili…
The dynamics of privatization and regulation of water services: a comparative study of two Spanish regions
2013
As in other economic activities, privatization of water delivery has not resulted in the retreat of the public sector, but rather a change in the way in which the government intervenes in the water industry. This paper illustrates this situation by comparing urban water services in two Spanish regions, Andalusia and Catalonia. Water service delivery is structured very differently in these two regions with respect to private involvement, the degree of market concentration and, as a result, problems in competition. The characteristics of the two regions' respective regulatory agencies reflect the different paths taken to privatization: in Catalonia private firms have much more tradition and o…
The Application of an Information System in the E-Government of Colombia to Improve Service to Citizens
2020
One of the main objectives of e-government is the use of data to improve processes, identify opportunities and make better decisions, this article describes a success story in the government of Colombia in building an information system that makes use of data exploitation techniques in one of the most important state entities in the country that guides, inspects, monitors and controls registry offices and notaries. The article describes the context and reasons why the project was carried out along with the architecture that was used to design and develop the information system that is currently used to monitor and control in a timely, clear, effective and efficient service delivery to citiz…
Consumer Motivations for Click-and-Collect and Home Delivery in Online Shopping
2018
Multichannel retailers are implementing cross-shopping options such as click-and-collect with the objective of better serving their customers. When consumers shop online to multichannel retailers they usually can choose between home delivery or click-and-collect (delivery at a nearby store). In this paper we investigate the consumers’ motivations behind this choice. Our results reveal that click-and-collect is explained by higher hedonic orientation whereas home delivery is explained by convenience orientation. Immediate gratification, and perceived delivery risk do not play a significant role in the choice.
Measurement of subpubic arch angle by three-dimensional transperineal ultrasound and impact on vaginal delivery
2015
Objectives To assess whether antepartum measurement of the subpubic arch angle (SPAA) as a parameter of the bony pelvic outlet can predict vaginal delivery. Methods Between January 2007 and June 2011, 625 nulliparous women with a singleton pregnancy were recruited from the antenatal clinic to be interviewed and have a four-dimensional transperineal ultrasound examination. Ultrasound examinations were performed between 34 and 36 weeks of gestation. Volume ultrasound data were saved for offline analysis, blinded against all other data. The SPAA was measured in the axial plane and logistic regression analysis was used to examine the association between SPAA and outcomes of vaginal delivery vs …