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Glove Selection for Work with Acrylates Including Those Cured by Ultraviolet, Visible Light, or Electron Beam
Published in Robert N. Phalen, Howard I. Maibach, Protective Gloves for Occupational Use, 2023
More than 50 different acrylic monomers are commercially available and used industrially. They range from monofunctional acrylates (i.e., with one acrylic double bond) to difunctional acrylates (i.e., with two acrylic double bonds) and to multifunctional acrylates (i.e., with three, four, five, or six acrylic double bonds). Table 23.1 provides examples of these main groups of acrylates (acrylic resins or monomers) associated with dermatitis and contact dermatitis, which are discussed in this chapter. They can be divided roughly into two categories: the rather well-defined molecules with narrow molecular weight distribution and the so-called alkoxylated (i.e., ethoxylated and propoxylated) types. The former category is mostly referred to by an acronym, an abbreviation of their chemical name. The more widely used monomers in this category are the following:TPGDA, tripropyleneglycol diacrylateHDDA, 1,6-hexanediol diacrylateTMPTA, trimethylolpropane triacrylate
The Effects of Synthetic Phosphonates on Living Systems
Published in Richard L. Hilderbrand, The Role of Phosphonates in Living Systems, 2018
A series of 4-alkyl derivatives of 2,6,7-trioxa-l-phosphabicyclo [2.2.2] octane, used as flame retardants, vinyl resin stabilizers, and antioxidants, has been found to be highly toxic.110,111 The toxicity is dependent on the nature of the 4-alkyl group, with the 4-isopropyl derivative having an LD50 of 0.18 mg/kg in the mouse or a toxicity some 30 times greater than diisopropylfluorophosphate.110 The same bicyclic phosphorus ester can be formed by the nonflaming combustion of trimethylol-propane based rigid-urethane foam containing O,O-diethyl-N,N-bis-(2-hydroxyethyl)aminomethyl phosphonate. The hazard involved is independent of flame contact or carbon monoxide intoxication and is exacerbated by the loss of the behavioral response to escape.112 The bicyclic phosphate esters have no effect on brain cholinesterase and may be antagonists to the response to y–aminobutyric acid. The isopropyl and t–butyl derivatives are more potent than bicuculline as antagonists to y–aminobutyric acid in the isolated frog spinal cord.111
Effect of different doses of borneol on the pharmacokinetics of vinpocetine in rat plasma and brain after intraocular administration
Published in Xenobiotica, 2020
Qun Ma, Manman Dai, Huimin Zhang, Luyu Bai, Ning He
The DTI were 1.12, 1.18, and 1.21 following treatment with VIN and 5, 10, and 20 mg/kg of borneol, respectively, and the middle and high doses of borneol resulted in obvious brain targeting effects. Similar results were reported by Ding et al. (2017). Cai et al. (2008) demonstrated that oral administration of gastrodin combined with borneol enhanced the absorption of gastrodin in the gastrointestinal tract and accelerated its distribution to the brain. The Tmax was increased from 60 to 120 min in plasma and from 60 to 90 min in the brain following intraocular administration of VIN combined with different doses of borneol. These results suggested that borneol may require time to penetrate and increase the permeability of the blood–brain barrier (BBB). These results agreed with those from a previous study (Yan et al., 2007), which reported that oral administration of trimethylolpropane phosphate (TMPP) with borneol the Tmax of TMPP was increased from 5 to 10 min in plasma and brain.
RNAi-based therapeutics for lung cancer: biomarkers, microRNAs, and nanocarriers
Published in Expert Opinion on Drug Delivery, 2018
Mariana Magalhães, Carmen Alvarez-Lorenzo, Angel Concheiro, Ana Figueiras, Ana Cláudia Santos, Francisco Veiga
Yan et al. developed polyester nanoparticles for selective siRNA delivery into lung cancer cells promoting the activation of genes involved in the regulation of apoptosis pathways. Functional polyesters were synthesized through the polycondensation of trimethylolpropane allyl ether (TPAE) with suberoyl chloride (diACl-C8) and pyridine, and then functionalized with amino thiols[132].
Intervention of 3D printing in health care: transformation for sustainable development
Published in Expert Opinion on Drug Delivery, 2021
Sujit Kumar Debnath, Monalisha Debnath, Rohit Srivastava, Abdelwahab Omri
Microneedle (MN) device consists of needles in micron size that are arranged in small patches. Traditional microneedles are limited with simple geometry. Several important parameters like microneedle size, shape, spacing, and composition are difficult to modify using the traditional method. WhereasThe advancement of 3D techniques accelerates the application of MNs by fabricating more sophisticated and complex geometry [47]. The continuous liquid interface production (CLIP) method was used to prepare the microneedle using polyacrylic acid, trimethylolpropane triacrylate, and derivatives of polyethylene glycol-polycaprolactone [62]. This SLA technique was also employed to fabricate polymeric MN arrays for enhancing cisplatin (an anticancer drug) delivery to A-431 epidermoid skin tumors in cancer treatment [63]. These MNs were fabricated with photopolymerizing consecutive layers of a biocompatible photopolymer resin followed by inkjet dispersion of coated cisplatin formulations. The piercing capacity (80% depth penetration) and mechanical properties of these MNs were improved significantly. A new MN fabrication method was designed in this study using polylactic acid by the FDM process. A post-fabrication chemical etching protocol was adopted to decrease the tip size by 1 µm. Prepared MN was successful to break off into porcine skin and cause less pain than a 26-gauge hypodermic needle [64]. A simple and flexible 3D printing-based fabrication of MN array templates was proposed using two-photon polymerization with improved precision and low cost [65]. The prepared arrays were efficiently invaded into two different skin models with the help of their sharp conical and pyramidal needles. These array design was simple, reproducible, and can be employed in effective drug delivery. A personalized MN for trigger fingers was developed using 3D printing technology. Prepared MN showed dual action on drug delivery and splinting of the affected finger. Significant higher diclofenac penetration through the skin was achieved by 0.5 hr [66]. Microfluidic architectures embedded with microneedles serve a new area that enables fluid management to deliver drugs through the transdermal route. A fabrication scheme was designed to create a hollow microneedle that interfaced with microfluidic structures in a single step [67]. Using stereolithography 3D printing, a complex architecture was created with lower cost and higher printing speed. To improve the individualized patient treatment and healthcare system, a novel device named 3DMNMEMS was developed combining with MN and microelectromechanical system (MEMS) [68]. An in vivo study demonstrated that the 3DMNMEMS successfully delivered insulin with improved glycemic control to diabetic animals compared to subcutaneous injections. There are several methods available to fabricate MNs using 3D printing. However, it is necessary to optimize the new design and dimensions of MNs for a clinical study. Currently, there are no 3DP MNs available in the market and no clinical studies have been reported yet [69]. Therefore, it is highly essential to explore the efficiency of 3D-printed MNs on humans through clinical trials.