Search results for "Polyester"
showing 10 items of 221 documents
In-situ forming gel-like depot of a polyaspartamide-polylactide copolymer for once a week administration of Sulpiride
2015
Abstract Objectives An in-situ forming gel-like depot, prepared by using an appropriate polyaspartamide-polylactide graft copolymer, has been employed to release in a sustained way sulpiride. Methods α,β-poly(N-2-hydroxyethyl)-D,L-aspartamide-g-polylactic acid (PHEA-g-PLA) has been used as a polymer component. Its physicochemical properties make possible to dissolve it in N-methyl-2-pyrrolidone, with the obtainment of a solution able to form a gel-like depot once injected into a physiological medium. Cell compatibility of PHEA-g-PLA depot has been investigated, using murine dermal fibroblasts as cell model. 3-(4,5-Dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazo…
Nanocarriers for optimizing the balance between interfollicular permeation and follicular uptake of topically applied clobetasol to minimize adverse …
2015
The treatment of various hair disorders has become a central focus of good dermatologic patient care as it affects men and women all over the world. For many inflammatory-based scalp diseases, glucocorticoids are an essential part of treatment, even though they are known to cause systemic as well as local adverse effects when applied topically. Therefore, efficient targeting and avoidance of these side effects are of utmost importance. Optimizing the balance between drug release, interfollicular permeation, and follicular uptake may allow minimizing these adverse events and simultaneously improve drug delivery, given that one succeeds in targeting a sustained release formulation to the hair…
Microfibrillar polymeric ocular inserts for triamcinolone acetonide delivery.
2019
Abstract Despite eye drops generally represent the most convenient, simple and patient-friendly formulations to treat ocular diseases, they suffer from poor retention on the ocular surface and low drug bioavailability leading to the necessity of prolonged and continuous treatment over time. Therefore, ocular insert could represent an innovative way to benefit from ocular topical administration while minimizing all the relevant limitation related to this route of administration. Polymeric non-erodible mucoadhesive ocular inserts should be comfortable and should rapidly adhere on the ocular surface, remain in situ for prolonged period, assure a reproducible and controlled drug release as well…
Engineering in-plane mechanics of electrospun polyurethane scaffolds for cardiovascular tissue applications
2021
Effective cardiovascular tissue surrogates require high control of scaffold structural and mechanical features to match native tissue properties, which are dependent on tissue-specific mechanics, function heterogenicity, and morphology. Bridging scaffold processing variables with native tissue properties is recognized as a priority for advancing biomechanical performance of biomedical materials and, when translated to the clinical practice, their efficacy. Accordingly, this study selected electrospinning on a rotating cylindrical target as an apparatus of broad application and mapped the relationship between key processing variables and scaffold mechanics and structure. This information was…
A methodology to assess the energetic valorization of bio-based polymers from the packaging industry: pyrolysis of reprocessed polylactide
2012
The energetic valorization process of bio-based polymers is addressed in this study, taking polylactide (PLA) as model. The pyrolysis of virgin and multiple-injected PLA was simulated by means of multi-rate linear-non-isothermal thermogravimetric experiments. A complete methodology, involving control of gases, thermal stability and thermal decomposition kinetics was proposed. The release of gases was monitored by Evolved Gas Analysis of the fumes of pyrolysis, by in-line FT-IR, with the aid of 2D-correlation IR characterization. A novel model to establish the thermal stability of PLAs under any linear heating profile was proposed. A kinetic strategy was methodically applied to assess the th…
Dual Enzyme-Responsive Capsules of Hyaluronic Acid-block-Poly(Lactic Acid) for Sensing Bacterial Enzymes.
2015
The synthesis of novel amphiphilic hyaluronic acid (HYA) and poly(lactic acid) (PLA) block copolymers is reported as the key element of a strategy to detect the presence of pathogenic bacterial enzymes. In addition to the formation of defined HYA-block-PLA assemblies, the encapsulation of fluorescent reporter dyes and the selective enzymatic degradation of the capsules by hyaluronidase and proteinase K are studied. The synthesis of the dual enzyme-responsive HYA-b-PLA is carried out by copper-catalyzed Huisgen 1,3-dipolar cycloaddition. The resulting copolymers are assembled in water to form vesicular structures, which are characterized by scanning electron microscopy, transmission electron…
MRI-Visible Poly(ε-caprolactone) with Controlled Contrast Agent Ratios for Enhanced Visualization in Temporary Imaging Applications
2013
International audience; Hydrophobic macromolecular contrast agents (MMCAs) are highly desirable to provide safe and efficient magnetic resonance (MR) visibility to implantable medical devices. In this study, we report on the synthesis and evaluation of novel biodegradable poly(ε-caprolactone)-based MMCAs. Poly(α-propargyl-ε-caprolactone-co-ε-caprolactone)s containing 2, 5, and 10 mol % of propargyl groups have been prepared by ring-opening copolymerization of ε-caprolactone and the corresponding propargylated lactone. In parallel, a diazido derivative of the clinically used diethylenetriaminepentaacetic acid (DTPA)/Gd3+ complex has been synthesized. Finally, MRI-visible poly(ε-caprolactone)…
Stable, hydroxyl functional polycarbonates with glycerol side chains synthesized from CO(2) and isopropylidene(glyceryl glycidyl ether).
2012
A series of functional polycarbonates, poly((isopropylidene glyceryl glycidyl ether)-co-(glycidyl methyl ether) carbonate) (P((IGG-co-GME) C)) random copolymers with different fractions of 1,2-isopropylidene glyceryl glycidyl ether (IGG) units, is synthesized. After acidic hydrolysis of the acetal protecting groups, a new type of functional polycarbonate prepared directly from CO(2) and glycerol is obtained, namely poly((glyceryl glycerol)-co-(glycidyl methyl ether) carbonate) (P((GG-co-GME) C)). All hydroxyl functional samples exhibit monomodal molecular weight distributions with PDIs between 2.5 and 3.3 and M(n) between 12 000 and 25 000 g mol(-1) . Thermal properties reflect the amorphou…
Biopolyester-based systems containing naturally occurring compounds with enhanced thermooxidative stability
2016
Background This work presents a sustainable approach for the stabilization of polylactic acid (PLA) against thermo-oxidative aging. Methods Naturally occurring phenolic and polyphenolic compounds, such as ferulic acid (FerAc), vanillic acid (VanAc), quercetin (Querc) and vitamin E (VitE), were introduced into PLA. Results The preliminary characterization of the systems formulated containing different amounts of natural stabilizers showed that all compounds used acted as plasticizers, leading to a decrease in rheological functions with respect to neat PLA, without significantly modifying the crystallinity of the raw material. The study of the thermo-oxidative behavior of neat PLA and PLA/nat…
Nanoparticle formulations as recrystallization inhibitors in transdermal patches
2020
Abstract Drug crystallization in transdermal patches is still a major challenge, confronting the formulation development of topical drug delivery systems. Encapsulation of drugs into nanoparticles is proposed here as a promising tool for regulating drug crystallization in transdermal patches. The degree of recrystallization and transdermal permeation of ibuprofen and hydrocortisone loaded in polymeric and lipid nanoparticles from matrix-type transdermal patches were investigated. Ethyl cellulose (EC4), poly (lactide-co-glycolic acid) (PLGA) and polycaprolactone (PCL) were employed for polymeric nanoparticle preparations; while medium chain triglyceride (MCT) and witepsol were used for the p…