Poly(butylene succinate--ε-caprolactone) Copolyesters: Enzymatic Synthesis in Bulk and Thermal Properties.

This work explores for the first time the enzymatic synthesis of poly(butylene--ε-caprolactone) (PBSCL) copolyesters in bulk using commercially available monomers (dimethyl succinate (DMS), 1,4-butanediol (BD), and ε-caprolactone (CL)). A preliminary kinetic study was carried out which demonstrated the higher reactivity of DMS over CL in the condensation/ring opening polymerization reaction, catalyzed by lipase B. PBSCL copolyesters were obtained with high molecular weights and a random microstructure, as determined by C NMR.

Copolymacrolactones Grafted with l-Glutamic Acid: Synthesis, Structure, and Nanocarrier Properties.

The enzymatic ring-opening copolymerization (eROP) of globalide (Gl) and pentadecalactone (PDL) was performed in solution from mixtures of the two macrolactones at ratios covering the whole range of comonomeric compositions. The resulting P(Gl--PDL) random copolyesters were aminofunctionalized by thiol-ene reaction with aminoethanethiol. ROP of γ-benzyl-l-glutamate -carboxyanhydride initiated by P(Gl--PDL)-NH provided neutral poly(γ-benzyl-l-glutamate)-grafted copolyesters, which were converted by hydrolysis into negatively charged hybrid copolymers.

Controlling the Isothermal Crystallization of Isodimorphic PBS--PCL Random Copolymers by Varying Composition and Supercooling.

In this work, we study for the first time, the isothermal crystallization behavior of isodimorphic random poly(butylene succinate)--poly(ε-caprolactone) copolyesters, PBS--PCL, previously synthesized by us. We perform nucleation and spherulitic growth kinetics by polarized light optical microscopy (PLOM) and overall isothermal crystallization kinetics by differential scanning calorimetry (DSC). Selected samples were also studied by real-time wide angle X-ray diffraction (WAXS).

Poly (α-Dodecyl γ-Glutamate) (PAAG-12) and Polylactic Acid Films Charged with α-Tocopherol and Their Antioxidant Capacity in Food Models.

Poly (α-dodecyl γ-glutamate) (PAAG-12) was successfully synthesized from poly(γ-glutamic acid) (PGGA) according to Nuclear Magnetic Resonance (NMR) analyses. PAAG-12 films were prepared and enriched with 5% α-tocopherol, with the aim of using them as novel antioxidant active packaging for food applications. Thermogravimetric Analysis (TGA) characterization determined that α-tocopherol improved thermal stability of films, which is beneficial for industrial processing.

Partially Renewable Poly(butylene 2,5-furandicarboxylate--isophthalate) Copolyesters Obtained by ROP.

Cyclic butylene furandicarboxylate ((BF)) and butylene isophthalate ((BI)) oligomers obtained by high dilution condensation reaction were polymerized in bulk at 200 °C with Sn(Oct)₂ catalyst via ring opening polymerization to give homopolyesters and copolyesters (PBFI) with weight average molar masses in the 60,000⁻70,000 g·mol range and dispersities between 1.3 and 1.9.

Comblike Ionic Complexes of Hyaluronic Acid and Alkanoylcholine Surfactants as a Platform for Drug Delivery Systems.

Nontoxic alkanoylcholine soaps ( nACh) were synthesized from choline and fatty acids with numbers of carbons n equal to 12, 14, 16, and 18, the latter including both saturated and 9- cis unsaturated alkanoyl chains. Coupling of nACh with hyaluronic acid (HyA) rendered comblike ionic complexes nACh·HyA that were non-water-soluble. The complexes were thermally stable up to temperatures above 200 °C but readily degraded by water, in particular when hyaluronidases were present in the aqueous medium.

Validation of Smart Nanoparticles as Controlled Drug Delivery Systems: Loading and pH-Dependent Release of Pilocarpine.

Micelles are good devices for use as controlled drug delivery systems because they exhibit the ability to protect the encapsulated substance from the routes of degradation until they reach the site of action. The present work assesses loading kinetics of a hydrophobic drug, pilocarpine, in polymeric micellar nanoparticles (NPs) and its pH-dependent release in hydrophilic environments. The trigger pH stimulus, pH 5.

Amphiphilic ionic complexes of hyaluronic acid with organophosphonium compounds and their antimicrobial activity.

Amphiphilic ionic complexes of hyaluronic acid and alkyltrimethylphosphonium soaps with alkyl chains containing even numbers of carbons from 12 to 22 have been produced. The complexes have a nearly stoichiometric composition, are non-water soluble, and are stable to heat up to temperatures above 200 °C. These complexes are amphiphilic and able to adopt a biphasic structure with the paraffinic and polysaccharide phases ordered arranged with a periodicity ranging between 3 and 5 nm depending on n.

Ionic coupling of hyaluronic acid with ethyl N-lauroyl l-arginate (LAE): Structure, properties and biocide activity of complexes.

Ethyl N-lauroyl l-arginate hydrochloride (LAE) was coupled with hyaluronic acid (HyA) to form ionic complexes with LAE to HyA ratios of 1:1 and 1:2. The complexes were extensively characterized by FTIR and NMR spectroscopies and their thermal properties evaluated by thermogravimetry and calorimetry. Thin films prepared from these complexes by casting displayed a smectic-like structure based on an ordered arrangement of LAE and HyA layers with a nanometric periodicity of 3.

Antibacterial Films Made of Ionic Complexes of Poly(γ-glutamic acid) and Ethyl Lauroyl Arginate.

The biocide agent LAE (ethyl -lauroyl l-arginate chloride) was coupled with poly(γ-glutamic acid) (PGGA) to form stable ionic complexes with LAE:PGGA ratios of 1 and 0.5. The nanostructure adopted by these complexes and its response to thermal changes were examined in detail by Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) using synchrotron radiation in real time.

Modulating the T of Poly(alkylene succinate)s by Inserting Bio-Based Aromatic Units via Ring-Opening Copolymerization.

Two series of aliphatic-aromatic copolyesters derived from succinic and 2,5-furandicarboxylic acids, and di--2-(hydroxyethyl) resorcinol as diol substituent of either 1,4-butanediol or ethylene glycol, respectively, were obtained by ring opening polymerization(ROP) performed in bulk and catalyzed by Sn(Oct)₂. Cyclic oligomers of furandicarboxylate of di--2-(hydroxyethyl) resorcinol were successfully synthesized by high-dilution condensation, and then copolymerized with cyclic oligomers of either butylene or ethylene succinate. The synthesized resorcinol-containing succinate-furanoatecopolyesters had oscillating between 50,000 and 30,000 g·mol depending on composition, and they all displayed a nearly random microstructure.

Crystalline structure and thermotropic behavior of alkyltrimethylphosphonium amphiphiles.

Quaternary organophosphonium salts bearing long alkyl chains are cationic surfactants of interest owing to their physical and biological properties. In the present work, the crystal structure and thermotropic behavior of the homologous series of alkyltrimethylphosphonium bromides (nATMP·Br), with the alkyl chain containing an even number (n) of carbon atoms from 12 to 22, have been examined within the 0-300 °C range of temperatures. These compounds were shown to be resistant to heat up to ∼390 °C.

Sugar-based bicyclic monomers for aliphatic polyesters: a comparative appraisal of acetalized alditols and isosorbide.

Three series of polyalkanoates (adipates, suberates and sebacates) were synthesized using as monomers three sugar-based bicyclic diols derived from D-glucose (Glux-diol and isosorbide) and D-mannose (Manx-diol). Polycondensations were conducted in the melt applying similar reaction conditions for all cases. The aim was to compare the three bicyclic diols regarding their suitability to render aliphatic polyesters with enhanced thermal and mechanical properties.

Isohexide and Sorbitol-Derived, Enzymatically Synthesized Renewable Polyesters with Enhanced T.

Sugar-based polyesters derived from sorbitol and isohexides were obtained via solvent-free enzymatic catalysis. Pendant hydroxyl groups, coming from the sorbitol units, were present along the polyester backbone, whereas the two isohexides, namely, isomannide and isoidide dimethyl ester monomers, were selected to introduce rigidity into the polyester chains. The feasibility of incorporating isomannide as a diol compared to the isoidide dimethyl ester as acyl-donor via lipase-catalyzed polycondensation was investigated.

Green and selective polycondensation methods toward linear sorbitol-based polyesters: enzymatic versus organic and metal-based catalysis.

Renewable polyesters derived from a sugar alcohol (i.e., sorbitol) were synthesized by solvent-free polycondensation.

Copolyesters made from 1,4-butanediol, sebacic acid, and D-glucose by melt and enzymatic polycondensation.

Biotechnologically accessible 1,4-butanediol and vegetal oil-based diethyl sebacate were copolymerized with bicyclic acetalized D-glucose derivatives (Glux) by polycondensation both in the melt at high temperature and in solution at mild temperature mediated by polymer-supported Candida antarctica lipase B (CALB). Two series of random copolyesters (PB(x)Glux(y)Seb and PBSeb(x)Glux(y)) were prepared differing in which d-glucose derivative (Glux diol or Glux diester) was used as comonomer. The three parent homopolyesters PBSeb, PBGlux, and PGluxSeb were prepared as well.

Nanoparticles of esterified polymalic acid for controlled anticancer drug release.

Esterification of microbial poly(malic acid) is performed with either ethanol or 1-butanol to obtain polymalate conjugates capable to form nanoparticles (100-350 nm). Degradation under physiological conditions takes place with release of malic acid and the corresponding alcohol as unique degradation products. The anticancer drugs Temozolomide and Doxorubicin are encapsulated in nanoparticles with efficiency of 17 and 37%, respectively.

Complexes of polyglutamic acid and long-chain alkanoylcholines: nanoparticle formation and drug release.

Ionic complexes of microbial poly(γ-glutamic acid) and alkanoylcholines are fully bio-based comb-like systems able to self-organize in an ordered amphiphilic structure made of hydrophobic and hydrophilic alternating layers. Incubation of complex films under physiological conditions for one month promoted dissociation of the complex and hydrolysis of the choline ester without almost degradation of polyglutamic acid. Complex decomposition rates were depending on alkanoyl chain length and on complex stoichiometry as well.

High T(g) bio-based aliphatic polyesters from bicyclic D-mannitol.

The carbohydrate-based diol 2,4:3,5-di-O-methylene-d-mannitol (Manx) has been used to obtain aliphatic polyesters. Manx is a symmetric bicyclic compound consisting of two fused 1,3-dioxane rings and bearing two primary hydroxyl groups. In terms of stiffness, it is comparable to the widely known isosorbide, but it affords the additional advantages of being much more reactive in polycondensation and capable of producing stereoregular polymers with fairly high molecular weights.

Comb-like ionic complexes of hyaluronic acid with alkyltrimethylammonium surfactants.

Stoichiometric complexes of hyaluronic acid with alkyltrimethylammonium surfactants bearing octadecyl, eicosyl and docosyl groups were prepared by ionic coupling in aqueous solution. The complexes were non soluble in water but soluble in organic solvents. In the solid state they self-assembled in a biphasic layered structure with the alkyl side chains forming a separate phase that melted in the 50-60 °C range.

Modification of Microbial Polymalic Acid With Hydrophobic Amino Acids for Drug-Releasing Nanoparticles.

Microbial poly(β, l-malic acid) was modified with either l-leucine ethyl ester (L) or l-phenylalanine methyl ester (F) to produce amphiphylic copolymers. The degradation of these copolymers in aqueous buffer took place under physiological conditions in a few weeks by hydrolysis of the side chain ester group followed by cleavage of the main chain. Spherical nanoparticles with diameters ranging between 70 and 230 nm were prepared from these copolymers by the dialysis-precipitation method.

Poly(methyl malate) nanoparticles: formation, degradation, and encapsulation of anticancer drugs.

PMLA nanoparticles with diameters of 150-250 nm are prepared, and their hydrolytic degradation is studied under physiological conditions. Degradation occurs by hydrolysis of the side chain methyl ester followed by cleavage of the main-chain ester group with methanol and L-malic acid as the final degradation products. No alteration of the cell viability is found after 1 h of incubation, but toxicity increases significantly after 3 d, probably due to the noxious effect of the released methanol.

Carbohydrate-based polyesters made from bicyclic acetalized galactaric acid.

The dimethyl ester of 2,3:4,5-di-O-methylene-galactaric acid (Galx) was made to react in the melt with 1,n-alkanediols HO(CH(2))(n)OH containing even numbers of methylenes (n from 6 to 12) to produce linear polycyclic polyesters. Two sets of poly(alkylene 2,3:4,5-di-O-methylene-galactarate) polyesters (PE-nGalx) with weight-average molecular weights in the ∼ 5000-10000 and ∼ 35000-45000 ranges were obtained using TBT and DBTO catalysts, respectively. For comparative purposes a set of poly(alkylene adipate) polyesters (PE-nAd) was also synthesized with molecular weights in the higher range using a similar procedure.

Hydrolyzable aromatic copolyesters of p-dioxanone.

Entropically driven ring-opening copolymerization of mixtures of a fraction of cyclic oligo(hexamethylene terephthalate)s composed of cycle sizes from 2 to 5 and p-dioxanone was used to prepare random copolyesters covering a range of aromatic (HT) to aliphatic (DO) units ratios from 9 to 1.3. The composition and microstructure of the copolyesters were accurately determined by (1)H and (13)C NMR, respectively.

Nanoconjugate Platforms Development Based in Poly(β,L-Malic Acid) Methyl Esters for Tumor Drug Delivery.

New copolyesters derived from poly(β,L-malic acid) have been designed to serve as nanoconjugate platforms in drug delivery. 25% and 50% methylated derivatives (coPMLA-Me(25)H(75) and coPMLA-Me(50)H(50)) with absolute molecular weights of 32 600 Da and 33 100 Da, hydrodynamic diameters of 3.0 nm and 5.