Search results for "Drug delivery systems"
showing 10 items of 304 documents
Synthesis and Characterization of Stimuli-Responsive Star-Like Polypept(o)ides: Introducing Biodegradable PeptoStars
2017
tar-like polymers are one of the smallest systems in the class of core crosslinked polymeric nanoparticles. This article reports on a versatile, straightforward synthesis of three-arm star-like polypept(o)ide (polysarcosine-block-polylysine) polymers, which are designed to be either stable or degradable at elevated levels of glutathione. Polypept(o)ides are a recently introduced class of polymers combining the stealth-like properties of the polypeptoid polysarcosine with the functionality of polypeptides, thus enabling the synthesis of materials completely based on endogenous amino acids. The star-like homo and block copolymers are synthesized by living nucleophilic ring opening polymerizat…
Towards chemical communication between gated nanoparticles.
2014
The design of comparatively simple and modularly configurable artificial systems able to communicate through the exchange of chemical messengers is, to the best of our knowledge, an unexplored field. As a proof-of-concept, we present here a family of nanoparticles that have been designed to communicate with one another in a hierarchical manner. The concept involves the use of capped mesoporous silica supports in which the messenger delivered by a first type of gated nanoparticle is used to open a second type of nanoparticle, which delivers another messenger that opens a third group of gated nanoobjects.We believe that the conceptual idea that nanodevices can be designed to communicate with …
The conjugation strategy affects antibody orientation and targeting properties of nanocarriers.
2021
Antibody-modified drug delivery systems in the nano-range have the ability to overcome current challenges for treating diseases due to their high specificity towards the targeted body region. However, no antibody-bound nanocarrier has been clinically approved to date. This missing clinical approval may be a result of the conjugation strategy that influences the spatial orientation of the attached antibody on the nanocarriers' surface. What is not missing, however, is a diverse selection of antibody to nanocarrier conjugation strategies that determine the success of an antibody functionalized drug delivery system. In this paper, two antibody conjugation strategies were compared by conjugatin…
In situ formation of steroidal supramolecular gels designed for drug release
2013
In this work, a steroidal gelator containing an imine bond was synthesized, and its gelation behavior as well as a sensitivity of its gels towards acids was investigated. It was shown that the gels were acid-responsive, and that the gelator molecules could be prepared either by a conventional synthesis or directly in situ during the gel forming process. The gels prepared by both methods were studied and it was found that they had very similar macroand microscopic properties. Furthermore, the possibility to use the gels as carriers for aromatic drugs such as 5-chloro-8-hydroxyquinoline, pyrazinecarboxamide, and antipyrine was investigated and the prepared two-component gels were studied with…
Anisotropy Influences on the Drug Delivery Mechanisms by Means of Joint Invariant Functions
2017
In the frame of Higuchi’s type functionality, this paper presents the anisotropy influences on the drug delivery mechanisms through the joint invariant functions to the simultaneous actions of the two SL(2R) isomorphic groups. Then, a new equation for drug delivery mechanism, independent of the type of polymer matrix and/or drug, is proposed.
Influence of cryogenic grinding on properties of a self-emulsifying formulation
2003
Abstract Recently, self-emulsifying drug delivery systems (SEDDS) have been developed as a method to deliver lipophilic drugs. Gelucire® 44/14 is an excipient, from the lauroyl macrogolglycerides family, producing a fine oil-in-water emulsion when introduced into an aqueous phase under gentle agitation as SEDDS, improving thereby solubility of poorly water-soluble drugs and their bioavailability. The aims of this study were to process Gelucire® 44/14 into a powder by cryogenic grinding to produce solid oral dosage forms and to investigate influence of this process on different properties of a formulation made of Gelucire® 44/14 and ketoprofen (90/10). Cryogenic grinding produced Gelucire® 4…
Colonic drug delivery: influence of cross-linking agent on pectin beads properties and role of the shell capsule type.
2006
For colonic delivery, pectin beads obtained by ionotropic gelation method have been already reported as an interesting approach. This study investigated the influence of the cross-linking agent (calcium or zinc) and the type of shell capsule used (classical or enteric capsules) on pectin beads properties and on their performance to target the colon (in vitro dissolution studies with subsequent pH change to mimic overall gastro-intestinal tract). Zinc pectinate beads seemed to be relatively similar to calcium's ones in morphological point, except on the surface aspect. When beads were introduced in classical hard capsules, ketoprofen release was not significantly different between CPG and ZP…
Colon-specific drug delivery: Influence of solution reticulation properties upon pectin beads performance.
2006
In this study, pectinate gel beads were produced by ionotropic gelation method with different solutions of cross-linking agents and ketoprofen was entrapped as model drug. The influence of these formulation parameters was investigated upon bead properties and upon their performance to target the colon. Zinc pectinate beads obtained with 10% of counter-ions solution at pH 1.6 exhibited the strongest gel network due to "egg-box" dimmer formation helped by hydrogen bonding. Furthermore the gel network formed at low pH was arranged in a compact three-fold conformation. Thus, this matrix structure in enteric capsules induced the lowest drug release in the upper gastro-intestinal tract (pH 1.2 fo…
Prodrug based on halloysite delivery systems to improve the antitumor ability of methotrexate in leukemia cell lines
2021
The prodrug approach, as well as the development of specific systems able to deliver a chemotherapeutic agent in the target site, decreasing the side effects often associated with its administration, are still a challenging. In this context, both methotrexate drug molecules (MTX) and biotin ligand moieties, whose receptors are overexpressed on the surface of several cancer cells, were loaded on halloysite nanotubes (HNTs) to develop nanomaterial based on multifunctional and "smart" delivery systems. To highlight the crucial role played by biotin, carrier systems based on HNTs and MTX were also synthetized. In detail, several approaches were envisaged: i) a supramolecular interaction between…
Liposome Formation from Bile Salt–Lipid Micelles in the Digestion and Drug Delivery Model FaSSIFmod Estimated by Combined Time-Resolved Neutron and D…
2011
The flow of bile secretion into the human digestive system was simulated by the dilution of a bile salt-lipid micellar solution. The structural development upon the dilution of the fed state bile model FeSSIF(mod6.5) to the fasted state bile model FaSSIF(mod) was investigated by small-angle neutron scattering (SANS) and dynamic light scattering (DLS) in crossed beam experiments to observe small and large structures in a size range of 1 nm to 50 μm in parallel. Because of the physiologically low lipid and surfactant concentrations of 2.625 mM egg-phosphatidylcholine and 10.5 mM taurocholate the sensitivity of the neutron-structural investigations was improved by partial solvent deuteration w…