Pseudo-Proteins and Related Synthetic Amino Acid-Based Polymers Promising for Constructing Artificial Vaccines
Mesut Karahan in Synthetic Peptide Vaccine Models, 2021
Interestingly, even acidic products, released after ester-bond’s hydrolysis of PP-PEUs before the ultimate biodegradation, did not cause inflammation that was ascribed to the self-buffering property of PEU preventing significant pH drop during the degradation process (Stakleff et al. 2013). Many PPs are amorphous and that provides smooth biodegradation of devices made of them. Other advantages of PPs over aliphatic polyesters, especially over the polyesters obtained via ROP are (Katsarava and Gomurashvili 2011; Katsarava, Kulikova, and Puiggalí 2016): Polycondensation synthesis without using toxic catalystsSynthesis under atmospheric conditions at moderate temperatures (20–80˚C)Tunable hydrophobicity/hydrophilicity balanceHigher affinity (owing to NHCO bonds) and better compatibility with tissuesSolubility in common organic solvents (ethanol, isopropanol, THF, acetone, etc.)Longer shelf-life
PEGylated Dendritic Nanoparticulate Carriers of Anti-Cancer Drugs
Mansoor M. Amiji in Nanotechnology for Cancer Therapy, 2006
Dagani (1996) discussed and compared hyperbranched polymers and dendrimers. Hyperbranched polymers have highly branched structure, but unlike dendrimers, their structure is neither regular nor highly symmetrical. The dendrimers were obtained by careful stepwise growth of successive layers or generations. Hyperbranched polymers are obtained in a single step by polycondensation of A2B monomers that contain two reactive groups of type A and one of type B. Functional groups A and B are selected in a way that they react with each other to form a covalent bond. Structure of hyperbranched polymers is thought to be intermediate between those of linear polymers and dendrimers. Because of steric constraints and statistical nature of coupling steps, hyperbranched polymers have irregular structures as some of the A groups remain unreacted, leading to incorporation of linear segments (i.e., monomers units coupled at two rather than three points) (Frechet 1994). Voit, Turner, and Mourey (1993) showed that viscosity-MW behavior of the hyperbranched polymers does not show a maximum as observed in the case of dendrimers. Instead, they obey the Mark–Hownick–Sakunada relation. Although their viscosities are anomalously lower when compared to linear polymers of comparable size. Analogous to dendrimers, A2B hyperbranched polymers had essentially same number of reactive groups as they have monomeric units. However, unlike dendrimers, these functional groups are not all located at chain ends (Frechet 1994).
Elements of Polymer Science
E. Desmond Goddard, James V. Gruber in Principles of Polymer Science and Technology in Cosmetics and Personal Care, 1999
Carothers, in 1929, classified synthetic polymers into two classes, according to the method of their preparation, i.e., condensation polymers and addition polymers. In polycondensation, or step-growth polymerization, polymers are obtained by reaction between two poly-functional molecules and elimination of a small molecule, for example water. Typical condensation polymers are shown in Figure 2. Addition (or chain reaction) polymers are formed from unsaturated monomers in a chain reaction. Examples of addition polymers are shown in Figure 2.
Synthetic biodegradable polyesters for implantable controlled-release devices
Published in Expert Opinion on Drug Delivery, 2022
Jinal U. Pothupitiya, Christy Zheng, W. Mark Saltzman
PCL can be synthesized from CL or 6-hydroxyhexanoic acid, which are both intermediates in the oxidation of cyclohexanol to adipic acid in microorganisms. Polycondensation of 6-hydroxyhexanoic acid to yield PCL requires harsh temperature and pressure conditions in the absence of catalysts [126]. The polymerization is feasible in the presence of catalysts at low temperatures; however, PCL formation proceeds sluggishly. ROP of CL is the preferred route to produce PCL. CL is commercially produced from the oxidation of cyclohexanone and subjected to ROP to yield high molecular weight PCL. ROP allows for fine tuning of molecular weight and produces polymers with low polydispersity in molecular weight; the polydispersity, or polydispersity index (PDI), is defined as the ratio of weight average molecular weight (Mw) and the number average molecular weight (Mn), PDI = Mw/Mn [126].
Terbinafine-loaded branched PLGA-based cationic nanoparticles with modifiable properties
Published in Pharmaceutical Development and Technology, 2019
Juraj Martiska, Eva Snejdrova, Martin Drastik, Ludmila Matysova, Milan Dittrich, Jan Loskot, Petr Jilek
Direct melt polycondensation method was used as method of polyester synthesis. Glycolic acid and dl-lactic acid (LA) in ratio of 1:1, and branching monomers dipentaerythritol (D) in concentration of 8%, tripentaerythritol (T) in concentration of 3%, or poly(acrylic acid) (PAA) in concentration of 2% (w/w) were used. The reaction mixture in the round bottom flask equipped with cooler to achieve gentle reflux was gradually heated to the temperature of 160 °C under controllably increasing vacuum provided by a rotary oil pump. At this temperature and a constant pressure of 550 Pa, the reaction continued for a total time of 20–50 h. The end of the reaction was monitored both by viscosity checking and based on a significant reduction of water vapor formation in a highly viscous melt. Figure 1 shows schemes of the structures.
Fluorescent melamine-formaldehyde/polyamine coatings for microcapsules enabling their tracking in composites
Published in Journal of Microencapsulation, 2022
Christian Neumann, Sophia Rosencrantz, Andreas Schmohl, Latnikova Alexandra
The polycondensation reaction of MF prepolymer and PEI (Table 1) took place in the aqueous phase yielding a suspension. After the end of the reaction (2 h), the suspension was left to stand for 10 min at room temperature and the filtrate was isolated by vacuum filtration (4–7 µm cellulose filter paper) and washed three times with 100 ml deionised water. The filter cake was quantitatively transferred to a glass vessel and allowed to dry overnight at room temperature. The weight of the white/yellow powder allowed to calculate the yield based on the amount of solids content of the starting materials used.
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