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Gloves
Published in Robert N. Phalen, Howard I. Maibach, Protective Gloves for Occupational Use, 2023
Marie-Noëlle Crépy, Pierre Hoerner
For polymer-coated gloves, after leaching, the mold is dipped in the polymer coating tank. In most cases, the polymer coating is used in the form of a water dispersion (polyacrylates, polyurethanes), but the polymer can also be used in the form of a solution in alcohol or other organic solvents.
Granulation of Poorly Water-Soluble Drugs
Published in Dilip M. Parikh, Handbook of Pharmaceutical Granulation Technology, 2021
Albert W. Brzeczko, Firas El Saleh, Hibreniguss Terefe
Polyacrylates and polymethacrylates are glassy materials that are produced by the polymerization of acrylic and methacrylic acid, and derivatives of these polymers such as esters amides and nitriles. They are primarily used in oral capsule and tablet formations as film-coating agents and are commonly known by the trade name of Eudragit®. Eudragit E is often used to improve drug release since it is soluble in gastric fluid below pH 5 and swells at high pH, while Eudragit L and S are water-insoluble and used as desired to avoid release in the stomach. Eudragit L is more permeable than Eudragit S grade, and films of varying permeability can be obtained by mixing the two types together. Their capability of forming a water-insoluble film coat finds most of their pharmaceutical applications in the formation of the sustained-release formulation. Eudragit L has been successfully used to increase the dissolution of griseofulvin and spironolactone at a pH value of 6.8 [119].
Polymer/Surfactant Interaction
Published in E. Desmond Goddard, James V. Gruber, Principles of Polymer Science and Technology in Cosmetics and Personal Care, 1999
E. Desmond Goddard, James V. Gruber
For systems charged in the opposite sense (HM-P ) an excellent example and summary of fluorescence results is provided in a compilation by Magny et al. for a series of hydrophobically modified polyacrylate copolymers, viz., and . (In the first case the molar amounts of the modifying dodecylacrylamide monomer were 1 and ; in the second it was octadecylacrylamide.) The interacting surfactant chosen was dodecyltrimethylammonium chloride (DTAC). (See Fig. 29.) The results show that the already strong interaction between the surfactant and the parent polyacrylate polymer is further reinforced by the presence on the polymer of dodecyl groups, that it is increased when the content of the latter is enlarged, and that the increase is even higher when the alkyl substitution is changed to octadecyl. Clearly, in the latter cases, the alkyl groups now appear to direct the micellization process. A point of much interest is that, using steady-state and time-resolved fluorescence methods, the authors were able to demonstrate that the total number of surfactant molecules and alkyl groups in the mixed micelles is close to the aggregation number of the free surfactant micelles. Similar work for a poly(maleic acid-coalkyl vinyl ether) group of polyanions in mixture with DTAC has been presented by Anthony and Zana (115). Finally, we refer to work by McCormick
A comparative evaluation of resin- and varnish-based surface protective agents on glass ionomer cement – a spectrophotometric analysis
Published in Biomaterial Investigations in Dentistry, 2020
Shreya Tyagi, Abi M. Thomas, Neeta Devi Sinnappah-Kang
The setting reaction of GIC involves neutralization of the polyacid by the basic glass leading to the formation of metal polyacrylate units [2]. The setting reaction involves the following stages: decomposition of the powder, gelation, hardening and maturation [3]. When the acid attacks the surface of the glass it leads to decomposition of the powder and the release of metallic cations into the solution. A silica gel is then formed and this surrounds the unreacted glass particles. The ions that are released from the glass powder are Na+ and Ca2+ (or Sr2+), followed quickly by Al3+ ions. These cations react with the polymer chains of carboxylate groups and thus increase the viscosity and contribute to the gelation reaction. Hardening of the cement occurs as a result of formation of crosslinks between the polymer chains and metal cations. Initially there is formation of calcium polyacrylate within 45 s followed by aluminium polyacrylate formation in 10 min and this continues for approximately a day. After the initial hardening, further reactions continue for more than 24 h and this is known as maturation [3–5]. With maturation of the cement, the physical properties change, i.e. there is an increase in strength and translucency of the GIC.
Recent advances in polymeric materials for the delivery of RNA therapeutics
Published in Expert Opinion on Drug Delivery, 2019
David Ulkoski, Annette Bak, John T. Wilson, Venkata R. Krishnamurthy
A variety of hydrolysable gene delivery systems have been developed to increase biodegradability and facilitate payload release in endosomal environments. As previously discussed, polyesters and polyacrylates have been widely investigated due to their susceptibility to hydrolysis in basic and acidic conditions (i.e. poly(β-amino esters)). Acetals, ketals, and hydrazones have also been used thoroughly employed as pH-labile linkages for the delivery of nucleic acids (Figure 4(b)) [216–218]. Although coformulations with pH-labile systems can induce transfection, the endosmolytic activity of polyesters and polyacrylates by themselves are limited and require additional components that provide mechanistic responses (e.g. ionizability) to control nanoparticle disassembly and efficient release of the RNA cargo.
Rheological and sensory properties of hydrophilic skin protection gels based on polyacrylates
Published in International Journal of Occupational Safety and Ergonomics, 2018
Agnieszka Kulawik-Pióro, Joanna Kurpiewska, Agnieszka Kułaszka
The acrylic acid derivatives used in the study were good thickeners, forming transparent gels of adequate durability. They created hydrophilic films on the surface of the skin, protecting it against hydrophobic substances. These films were easy to remove using water. Polyacrylates can thus be used in industry to produce hydrophilic barrier creams for skin protection.The hydrophilic barrier gels with a lower yield point had a lighter texture, and hence were easier to spread on the skin.The correlation demonstrated between the rheological analysis results and the barrier property evaluation of the creams confirmed the possibility of defining the characteristics which are important from the user’s point of view.