Encapsulation–release property of amphiphilic hyperbranched d-glucan as a unimolecular reverse micelle

Structural and viscosity studies of dendritic hyper branched polymer as viscosity index improvers

Star-like structural compounds were synthesized from different moles % of either dodecyl acrylate or triethylenetetramine using a one-pot commercial synthesis technique. The polymers that were created had various terminations. Fourier Transform Infrared (FTIR) spectroscopy and 1HNMR were used to verify the produced polymers' chemical composition with different terminations. Furthermore, by analysis of Dynamic Light Scattering (DLS), the size and distribution of the synthesised branched polymers were evaluated. Using a Gel-permeation chromatograph, the modified hyperbranched polymer's molecular weight, synthesized with various end points, were assessed. The unorganized structured prepared compounds with various molar feed ratios dodecyl acrylate: triethylenetetramine (DDA: TETA) was designed as A, B, C, D and E. Moreover, the synthesized additives function as viscosity index improvers (VII). As the concentration of polymeric additives increases, it leads to higher VI values. Similarly, with the increase in percentage of triethylenetetramine in the prepared hyperbranched polymers, the VI also increases. Notably, the most effective VI achieved is (E) = 212. It is noteworthy that all the synthesized hyperbranched polymers exhibited Newtonian behavior in the rheological study.

Approaches for the preparation of non-linear amphiphilic polymers and their applications to drug delivery

Amphiphilic polymers are particularly useful for drug delivery because of their ability to self-assemble into discrete aggregates. While this behavior has been studied in depth for simple linear block copolymer amphiphiles, recent advances in synthetic methodologies have provided efficient routes to amphiphilic polymers with more complex architecture, including dendrimers, hyperbranched polymers, star polymers, and cyclic polymers. These architectures can impart unique advantages, such as increased stability, on their micellar aggregates. Herein the different strategies for preparing these complex amphiphiles are described, and the application of their assemblies towards drug delivery are summarized.

Synthesis of Hyperbranched Polymer Using Slow Monomer Addition Method

This paper details the synthesis of a well-defined hyperbranched polymer using a slow monomer addition method. The polymerization under slow monomer addition conditions results in a very low monomer concentration actually present in the reaction mixture, and the exclusive reaction of the monomer with the growing polyfunctional macromolecules occurs, resulting in a high molecular weight and a high degree of branching value. Thus, the slow monomer addition is a versatile and preferential method for the controlled synthesis of a well-defined hyperbranched polymer with both a high molecular weight and a high degree of branching value.

Enhancement of plant and bacterial lectin binding affinities by three-dimensional organized cluster glycosides constructed on helical poly(phenylacetylene) backbones

A series of poly(phenylacetylene)s bearing diverse saccharide pendants--N-acetyl-D-glucosamine, D-lactose, and N-acetyl-D-neuraminic acid--were synthesized by rhodium-mediated polymerizations of the corresponding acetyl-protected glycosylated phenylacetylenes followed by deprotection. The circular dichroism spectra of these glycosylated poly(phenylacetylene)s each displayed split-type Cotton effects in the long absorption region of the conjugated polymer backbone (260-500 nm), thus indicating predominantly one-handed helical conformations in their backbones. The binding affinities of these glycosylated poly(phenylacetylene)s, and those of previously reported phenylacetylenes bearing D-galactose, towards plant and bacterial lectins were investigated by hemagglutination inhibition assay and isothermal titration calorimetry (ITC). The stoichiometries of binding vary strongly, depending on the lectin binding sites and the accessibilities of the carbohydrate residues in the helices. The measured affinities also vary, with the maximum value observed for the interaction between poly-PA-α-Gal and lectin I from Pseudomonas aeruginosa, with a K(d) value of 4 μM per monosaccharide representing a 200-fold increase relative to the corresponding monomer.

Self-assembled micelles based on hydrophobically modified quaternized cellulose for drug delivery

Novel amphiphilic cationic cellulose (HMQC) derivatives carrying long chain alkyl groups as hydrophobic moieties and quaternary ammonium groups as hydrophilic moieties were synthesized. Structure and properties of the amphiphilic cellulose derivatives were characterized by elemental analysis, FT-IR, (1)H NMR, ζ-potential measurement, dynamic light scattering (DLS), fluorescence spectroscopy and transmission electron microscopy (TEM). The results revealed that HMQCs can be self-assembled into cationic micelles in distilled water with the average hydrodynamic radius of 320-430 nm. The cytotoxicity study showed that the HMQC exhibited low cytotoxicity. Prednisone acetate, a water insoluble anti-inflammation drug, was chosen as a model drug to investigate the utilization of self-assembled HMQC micelles as a delivery carrier for poorly water-soluble drugs. The study indicated that the prednisone acetate could be incorporated effectively in the self-assembled HMQC micelles and be controlled released.

Synthesis of Hyperbranched Carbohydrate Polymers by Ring-Opening Multibranching Polymerization of Anhydro Sugar

The synthesis of novel hyperbranched carbohydrate polymers, prepared by the ring-opening multibranching polymerizations of anhydro and dianhydro sugars, is described. The hyperbranched carbohydrate polymers were formed by the cationic polymerization of 1,6-anhydro-beta-D-hexopyranose, 1,4-anhydrotetritol, 2,3-anhydrotetritol, and 1,2:5,6-dianhydro-D-mannitol. These polymerizations proceeded without gelation to produce water-soluble hyperbranched carbohydrate polymers with controlled molecular weights and narrow polydispersities. The values for the degree of branching of the polymers were in the range of 0.28-0.50. The polymerization method, which proceeds through a ring-opening reaction by a proton-transfer reaction mechanism, is a facile method leading to a spherical carbohydrate polymer with a high degree of branching.