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Selection Considerations for Membranes and Models for In Vitro/Ex Vivo Permeation Studies
Published in Tapash K. Ghosh, Dermal Drug Delivery, 2020
Pei-Chin Tsai, Tannaz Ramezanli, Dina W. Ameen, Sonia Trehan, Nathaly Martos, Zheng Zhang, Bozena Michniak-Kohn
Silicone membrane is based on silicone polymers whose backbone is composed of silicon-oxygen (Si-O) units. Among those silicone polymers, polydimethylsiloxane (PDMS) is the basic form, in which two methyl groups are linked to each silicon molecule. PDMS has unique properties such as high flexibility, low glass transition temperature and high gas permeability.74 The properties of silicone polymers can be tuned by modifying the chemical structure of PDMS. For example, an important modification to PDMS is the incorporation of vinyl groups, which significantly increases the cross-linking efficiency with organic peroxide. Methyl-vinyl silicone is a widely used silicone rubber.
Nasal and Facial Fractures
Published in John C Watkinson, Raymond W Clarke, Louise Jayne Clark, Adam J Donne, R James A England, Hisham M Mehanna, Gerald William McGarry, Sean Carrie, Basic Sciences Endocrine Surgery Rhinology, 2018
Significant orbital floor injury requires exploration and repair. The approach will be determined by the size and position of the blow-out fracture. All soft-tissue components should be mobilized and supported by a graft. Various grafts and materials have been used for this purpose. polydimethylsiloxane (PDS) are readily available and most suited for smaller defects. Titanium alloplasts, either prefabricated or custom-made using CAD-CAM technology are extremely useful especially when there are concomitant zygomatic complex fractures.42
Reproductive and Developmental Toxicity Studies by Cutaneous Administration
Published in Rhoda G. M. Wang, James B. Knaak, Howard I. Maibach, Health Risk Assessment, 2017
Rochelle W. Tyl, Raymond G. York, James L. Schardein
Two forms of polydimethylsiloxane used as prosthesis implant materials were not developmentally toxic when administered dermally to rabbits at doses of 200 or 1000 mg/kg of either a 10- or 350-centistroke material.137 Neither form was developmentally toxic when given subcutaneously at the same dosages.
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].
A method for the tribological assessment of oral pharmaceutical liquids
Published in Drug Development and Industrial Pharmacy, 2022
Hyun Joo Lee, R. Gary Hollenbeck, Jill A. Morgan, Amy Kruger Howard, Akhtar Siddiqui, Vilayat A. Sayeed, Arzu Selen, Stephen W. Hoag
Unlike rheology which measures the bulk properties of a sample, tribology is a system property that is a function of the (1) measurement geometry (ring on a plate, mini traction machine (MTM), three balls on a plate and ball on three plates), (2) surface characteristics (tribo-pairs), and (3) the lubricating liquid. For more background on these experimental instrument configurations, see Shewan et al. [9]. From previous research in the food science literature, it is known that these three parameters must be carefully controlled to get good measurements [24,25], and methods should be carefully validated to get reproducible results [26]. To date, there have been few tribological studies of pharmaceutical suspensions, which are critical dosage forms for pediatric patients. The studies that have looked at the texture properties of suspensions have either been based upon patient preference [17,22] or done using tribological measurements [1,13]. In terms of the measurement geometry, most of the suspension studies have used the MTM geometry [1,13]; however, other geometries such as the ring on plate method have some advantages and merit investigation [9]. In terms of the surfaces, most researchers in the food industry use polydimethylsiloxane (PDMS) [27,28], and some studies have used other materials like excised pig tongue and 3M surgical tape [14,29]. To date, most of the suspension studies on pharmaceutical suspensions have used PDMS [1].
Antifouling properties of amphiphilic poly(3-hydroxyalkanoate): an environmentally-friendly coating
Published in Biofouling, 2021
A. Guennec, L. Brelle, E. Balnois, I. Linossier, E. Renard, V. Langlois, F. Faÿ, G. Q. Chen, C. Simon-Colin, K. Vallée-Réhel
Poly[(3-hydroxybutyrate)-co-(3-hydroxyvalerate)] (PHBHV) containing 30 mol % of 3-hydroxyvalerate was purchased from Pacific Biotech (Thailand). Poly[(3-hydroxybutyrate)-co-(3-hydroxyhexanoate)]) (PHBHHx) with 20 mol% of HHx was supplied by CHEN Georges, Tshingua University, China. Polydimethylsiloxane (PDMS) was obtained from Momentive Performance Materials (France) as the trade mark RTV-615. O-(2-Mercaptoethyl)-O′-methylpolyethylene glycol (Mn = 2000 g mol−1) named ‘PEGSH’, 2,2-dimethoxy-2-phenylacetophenone (DMPA), allyl alcohol, dibutyltin dilaurate (DBTL), dichloromethane, Guillard’s F/2 Marine Enrichment Basal Salt Mixture, NaCl, tryptone, antibiotics, yeast extract were purchased from Sigma Aldrich, Shanghai, China. A commercial PDMS-PEG copolymer, traded under the name CoatOsil 7602, was obtained from Momentive Performance Materials (France). The copolymer has a molar mass of about 3000 g mol−1 and presents a grafted structure, as revealed by carbon and proton NMR. The copolymer contains 20–50 EO units per PDMS chain (Gillet et al. 2018).