Polyvinylpyrrolidone (PVP) has been incorporated over the years into numerous hydrogel contact lenses as both a primary matrix component and an internal wetting agent to increase lens wettability. In this study, complementary analytical techniques were used to characterize the PVP wetting agent component of senofilcon A and samfilcon A contact lenses, both in terms of chemical composition and amount present. Photo-differential scanning calorimetry (photo-DSC), gas chromatography with a flame ionization detector (GC-FID), and high-resolution/accurate mass (HR/AM) liquid chromatography-mass spectrometry (LC-MS) techniques confirmed dual phase reaction and curing of the samfilcon A silicone hydrogel material. Gel permeation chromatography (GPC) demonstrated that high molecular weight (HMW) polymer was present in isopropanol (IPA) extracts of both lenses. High-performance liquid chromatography (HPLC) effectively separated hydrophilic PVP from the hydrophobic silicone polymers present in the extracts. Collectively, atmospheric solids analysis probe mass spectrometry (ASAP MS), Fourier transform infrared (FTIR) spectroscopy, H nuclear magnetic resonance (NMR) spectroscopy, GC-FID, and LC-MS analyses of the lens extracts indicated that the majority of NVP is consumed during the second reaction phase of samfilcon A lens polymerization and exists as HMW PVP, similar to the PVP present in senofilcon A. GC-FID analysis of pyrolyzed samfilcon A and senofilcon A indicates fourfold greater PVP in samfilcon A compared with senofilcon A. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 1064-1072, 2018.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1002/jbm.b.33904 | DOI Listing |
Nat Commun
January 2025
Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan, China.
Inspired by counterintuitive water "swelling" ability of the hydrophobic moss of the genus Sphagnum (Peat moss), we prepared a hydrophobic pseudo-hydrogel (HPH), composed of a pure hydrophobic silicone elastomer with a tailored porous structure. In contrast to conventional hydrogels, HPH achieves absorption-induced volume expansion through surface tension induced elastocapillarity, presenting an unexpected absorption-induced volume expansion capability in hydrophobic matrices. We adopt a theoretical framework elucidating the interplay of surface tension induced elastocapillarity, providing insights into the absorption-induced volume expansion behavior.
View Article and Find Full Text PDFWater Environ Res
January 2025
Zhejiang Key Laboratory of Petrochemical Environmental Pollution Control, Zhejiang Ocean University, Zhoushan, P. R. China.
The discharge of oil-laden wastewater from industrial processes and the frequent occurrence of oil spills pose severe threats to the ecological environment and human health. Membrane materials with special wettability have garnered attention for their ability to achieve efficient oil-water separation by leveraging the differences in wettability at the oil-water interface. These materials are characterized by their simplicity, energy efficiency, environmental friendliness, and reusability.
View Article and Find Full Text PDF3D Print Med
January 2025
Department of Surgical & Interventional Engineering, School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK.
Background: Penile implant surgery is the standard surgical treatment for end-stage erectile dysfunction. However, the growing complexity of modern high-tech penile prostheses has increased the demand for more practical training opportunities. The most advanced contemporary training methods involve simulation training using cadavers, with costs exceeding $5,000 per cadaver, inclusive of biohazard fees.
View Article and Find Full Text PDFClin Exp Optom
January 2025
Eurolens Research, Division of Pharmacy and Optometry, The University of Manchester, Manchester, UK.
Clinical Relevance: Knowledge of contact lens prescribing trends can (a) assist practitioners to benchmark their own prescribing habits, (b) help the contact lens industry understand preferred products, and (c) support academics in scholarly writings.
Background: This work aims to document contact lens prescribing trends in Australia over the past quarter of a century.
Methods: An annual survey of contact lens prescribing trends was conducted in Australia each year from 2000 to 2024, inclusive, by asking optometrists to provide information relating to 10 consecutive contact lens fits undertaken between January and March.
Turk J Ophthalmol
December 2024
Muğla Sıtkı Koçman University Faculty of Medicine, Department of Ophthalmology, Muğla, Türkiye.
Objectives: To compare the efficacy of two different silicone hydrogel bandage contact lenses (BCLs) in terms of visual rehabilitation and ocular discomfort following photorefractive keratectomy (PRK).
Materials And Methods: This prospective study included 60 eyes of 30 patients who underwent bilateral PRK surgery to correct myopia and/or astigmatism refractive errors. Following surgery, lotrafilcon A BCLs were applied to the right eye and senofilcon A BCLs were applied to the left eye.
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!