Synthetic Polymers in Cosmetics
E. Desmond Goddard, James V. Gruber in Principles of Polymer Science and Technology in Cosmetics and Personal Care, 1999
As mentioned earlier, the newer PAA resins, which incorporate cross-linking and/ or hydrophobic modifications, have surpassed the performance attributes of the simple homopolymers, especially in personal care applications. Although very little pure PAA or PMA homopolymer is employed in the industry today, many of the properties discussed above for the homopolymers still apply to these more complex PMAs. Poly(acrylamide). Homopolymeric poly(acrylamide), while having significant commercial and industrial usefulness, has found limited success in personal care applications compared to its acrylic acid cousin . Commercial poly(acrylamide), 4, which is a homopolymer made by polymerization of acrylamide, 3, actually has a finite number of hydrolyzed amide groups, 5, (Fig. 7). This affords a polymer structurally and chemically not unlike PAA. In fact, it may be the sensitivity of the amide group to hydrolysis that causes formulators to simply develop products using PAA directly. Also, hydrolysis of poly(acrylamide) affords ammonia as a by-product, which imparts an unacceptable and difficult-to-mask “fishy” odor.
In vivo dosimetry II: Brachytherapy
Sam Beddar, Luc Beaulieu in Scintillation Dosimetry, 2018
To maximize the amount of scintillator light transmitted, the optical fiber material needs to be highly transparent to light in the wavelength range emitted by the scintillator, commonly in the blue region. Silica is a common material for optical fibers and is transparent to light in this wavelength range, but becomes too rigid with larger diameters needed in this application. Poly(methyl methacrylate) (PMMA) is also transparent to visible light and is more flexible than silica. PMMA fibers with diameters of 1 and are readily available and are suitable light guides for most applications. The higher the numerical aperture of the optical fiber, the more light from the scintillator will couple into it. The numerical aperture of a PMMA fiber is typically close to 0.5, for example with a refractive index of 1.492 in the core and 1.405 in the cladding.
Vaccine Adjuvants in Immunotoxicology
Mesut Karahan in Synthetic Peptide Vaccine Models, 2021
Nanoparticles are manufactured using albumin, collagen, starch, chitosan, and dextran out of natural polymers and polymethylmethacrylate, polyesters, polyanhydrides, and polyamides among synthetic polymers (Li et al. 2014). There are biodegradable or non-biodegradable polymers. Non-biodegradable polymers may cause unexpected effects by accumulation in the body. In the vaccine studies, the characteristics such as toxic effects of the polymer on the organism, antigen release speed capacity, stability status under storage conditions, and stability in the in vivo conditions should be taken into account in making a decision for an ideal polymer carrier system (Skwarczynski and Toth 2011, 2016). The comprehensive toxicity tests for several synthetic polymers such as polyesters, polylactic acid (PLA), polyglycolic acid, and their copolymers poly(lactic-co-glycolic acid) (PLGA) have been carried out and they are FDA-approved for use in humans (Li et al. 2014; Cordeiro and Alonso 2016). The most commonly used biodegradable polymers are PLA, PLGA, polyglutamic acid (PGA), polycaprolactone (PCL), and polyhydroxybutyrate. PLGA is the most frequently used polymer in the nanoparticle studies (Li et al. 2014). Skwarczynski and Toth (2011) have reported in their study that MUC-1 peptide vaccine assembled into PLGA nanoparticle carrier system accompanied with adjuvant MPLA created immune response by inducing T cells. However, it has been noted in the same article that need for use of adjuvant in the PLGA-based systems still continues (Skwarczynski and Toth 2011).
Microneedles for transdermal drug delivery using clay-based composites
Published in Expert Opinion on Drug Delivery, 2022
Farzaneh Sabbagh, Beom Soo Kim
Carboxymethylcellulose (CMC) is a type of cellulose derivative in which a carboxymethyl group (-CH2-COOR) is bonded to a part of the hydroxyl group present in the cellulose skeleton [92]. Polar carboxyl groups make cellulose chemically reactive, soluble, and hydrophilic. However, the main disadvantage of natural polymer-based hydrogels is poor mechanical properties due to large swelling [93]. Attempts have been made to overcome these problems by using various types of grafting, developing interpenetrating polymer networks and nanofillers, or altering the structure by physically mixing with other polymers. Poly (acrylic acid) is a hydrophilic polymer due to the presence of hydrophilic -COOH groups and can absorb huge amounts of water. Therefore, poly(acrylic acid) is widely used in drug delivery systems [67].
Chimeric liposomes incorporating functional copolymers: preparation and pH/thermo-responsive behaviour in aqueous solutions
Published in Journal of Liposome Research, 2021
Theodore Sentoukas, Costas Demetzos, Stergios Pispas
Poly(2-(dimethyl amino ethyl) methacrylate) (PDMAEMA) is a pH and thermo-responsive polymer with pKa = 7.3 at 25 °C and a Lower Critical Solution Temperature (LCST) around 45 °C, depending on molecular weight and pH of the aqueous solution. The latter depicts the hydrophilicity of the PDMAEMA at temperatures under the LCST, while a temperature increase over the LCST leads to the breakage of hydrogen bonds between the polymer and water molecules, resulting into a more hydrophobic character. At pH 3, PDMAEMA is fully protonated, fully soluble in water and thus loses its thermo-responsive behaviour. At pH 7, PDMAEMA is partially protonated and exhibits a thermal transition in the form of LCST, which depends mostly on its molecular weight (Niskanen et al. 2013, Fujii et al. 2017). On the other hand, poly(stearyl methacrylate) (PSMA), or poly(octadecyl methacrylate), comes with a long hydrocarbon crystallizable side chain, making it a highly hydrophobic polymer (Ahmed et al. 2017).
Critical design parameters to develop biomimetic organ-on-a-chip models for the evaluation of the safety and efficacy of nanoparticles
Published in Expert Opinion on Drug Delivery, 2023
Mahmoud Abdelkarim, Luis Perez-Davalos, Yasmin Abdelkader, Amr Abostait, Hagar I. Labouta
Materials that were often used are silicon and glass, which enable cell adhesion but with a lower stability [132]. Thermoplastics such as poly(methyl methacrylate) (PMMA), cyclic olefin copolymer (COC), polystyrene, and poly(ethylene terephthalate) have high mechanical strength but with greater hydrophobicity [133]. Two procedures of surface treatment were applied to decrease the hydrophobicity of thermoplastics; the first is dynamic coating with ionic or nonionic small molecules, and the second is permanent chemical modification [134]. Polymers have higher biocompatibility with lower toxicity. Of which, polydimethylsiloxane (PDMS) is the most commonly used material for microfluidic device fabrication [135]. PDMS provides greater flexibility for different dynamic flows, enhances more oxygen supply to cells due to their gas permeability as well as they have high optical clarity that allows immunostaining and imaging [136]. Plasma treatment was found to lower the hydrophobicity of PDMS, but the effect is short due to the hydrophobic recovery [137]. Surface coating with other biomaterials such as collagen, gelatin, and hydrogels act as an extracellular matrix that induces cell adhesion, proliferation, and better cell growth. It allows cells to communicate, organize and provide the required mechanical stress on the cells with low antigenicity, in addition to chitosan, which is more flexible and porous to cells [138,139].
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