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  • Wiley  (3)
  • Szurman, Peter  (3)
  • 1
    In: Acta Ophthalmologica, Wiley, Vol. 101, No. 4 ( 2023-06), p. 422-432
    Abstract: Hydrogel‐based vitreous substitutes have the potential to overcome the limitations of current clinically used endotamponades. With the goal of entering clinical trials, the present study aimed to (I) transfer the material synthesis of hyaluronic acid–based hydrogels into a routine, pharmaceutical‐appropriate production and (II) evaluate the properties of the vitreous substitutes in terms of the current regulations for medical devices (MDR/ISO standards). Methods The multistep manufacturing process of the vitreous substitutes, including the modification of hyaluronic acid with glycidyl methacrylate, photocopolymerization with N ‐vinylpyrrolidone, and successive hydrogel purification, was developed under laboratory conditions, characterized using 1 H‐NMR, FT‐IR and UV/Vis spectroscopies and HPLC, and transferred towards a pharmaceutical production environment considering GMP standards. The optical and viscoelastic characteristics of the hyaluronic acid–based hydrogels were compared with those of extracted human vitreous and silicone oil. The effect of the hydrogels on the metabolic activity, proliferation and apoptosis of fibroblast (MRC‐5, BJ, L929), retinal pigment epithelial (ARPE‐19, hiPSC‐derived RPE) and photoreceptor cells (661W) was studied as well as their mucosal tolerance via a HET‐CAM assay. Results Hyaluronic acid–based hydrogels having a suitable purity, sterility, high transparency ( 〉 90%), appropriate refractive index (1.3365) and viscoelasticity (G′  〉  G″) were prepared in a standardized manner under controlled process conditions. The metabolic activity, proliferation and apoptosis of various cell types as well as egg choroid were unaffected by the hyaluronic acid–based vitreous substitutes, demonstrating their biocompatibility. Conclusions The present study demonstrates the successful transferability of the crucial synthesis steps of hyaluronic acid–based hydrogels into a routine, GMP‐compliant production process while achieving the optical and viscoelastic properties, biocompatibility and purity required for their clinical use as vitreous substitutes.
    Type of Medium: Online Resource
    ISSN: 1755-375X , 1755-3768
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2023
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  • 2
    In: Acta Ophthalmologica, Wiley, Vol. 99, No. 7 ( 2021-11)
    Abstract: To analyse the cytotoxic and antiproliferative effect of methotrexate (MTX) and fluorouracil (5‐FU) in vitro on fibroblasts, retinal pigment epithelial (RPE) and photoreceptor cells as an adjunct for reducing the incidence of proliferative vitreoretinopathy (PVR) after rhegmatogenous retinal detachment surgery. Methods Methotrexate and 5‐FU were dissolved separately in balanced salt solution (BSS) with concentrations ranging from 0–8000 µg/ml and 0–4000 µg/ml, respectively. All solutions were analysed in terms of pH and osmolarity and applied for 1 h to fibroblasts (BJ), RPE (ARPE‐19) and photoreceptor (661W) cell lines adherently cultivated in 96‐well cell culture plates (10 000 cells/well). 24 h after incubation, the proliferative (BrdU), metabolic (CellTiter‐Glo) and apoptotic (Caspase 3/7) activity of the cells were examined in vitro. Results 5‐FU had an antiproliferative effect on BJ and ARPE‐19 cells starting from low concentrations (2 µg/ml). However, the viability of 661W cells decreased and apoptosis was induced with increasing 5‐FU concentration. In contrast, MTX up to a concentration of 266 µg/ml did neither result in a significant loss of viability nor in increased caspase 3/7 activity of BJ, ARPE‐19 and 661W cells and inhibited the proliferation of ARPE‐19 already at low concentrations starting from 8 µg/ml. Conclusions Methotrexate dissolved in BSS is biocompatible up to a concentration of 266 µg/ml and may act as an intraoperative rinse solution to inhibit RPE proliferation in PVR‐diseased eyes. Contrary, the use of 5‐FU within the posterior segment of the eye is limited by its cell‐damaging effect on photoreceptor cells.
    Type of Medium: Online Resource
    ISSN: 1755-375X , 1755-3768
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2021
    detail.hit.zdb_id: 2466981-7
    Location Call Number Limitation Availability
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  • 3
    In: Acta Ophthalmologica, Wiley, Vol. 101, No. 6 ( 2023-09), p. 687-695
    Abstract: To assess the safety and performance of hyaluronic acid‐based vitreous substitutes in phthitic eyes. Methods In this retrospective interventional study a total of 21 eyes from 21 patients with phthisis bulbi were treated at the Eye Clinic Sulzbach between August 2011 and June 2021. Patients who underwent a 23G pars plana vitrectomy received a vitreous substitute composed of (I) a non‐crosslinked hyaluronic acid (Healon GV), (II) a crosslinked hyaluronic acid‐based hydrogel (UVHA), or (III) silicone oil (SO‐5000). Main outcome measures were the intraocular pressure (IOP), the visual acuity and the structural integrity of the retina and choroid assessed by optical coherence tomography. Results An increase in IOP ≥ 5 mmHg was achieved with SO‐5000 in 5/8 eyes (6/10 interventions, 60.0%) for 36.4 ± 39.5 days, with Healon GV in 4/8 eyes (7/11 interventions, 63.6%) for 82.6 ± 92.5 days and with UVHA in 4/5 eyes (5/6 interventions, 83.3%) for 93.6 ± 92.5 days. Visual acuity increased in 5/21 eyes (23.8%), remained constant in 12/21 eyes (57.1%) and decreased in 4/21 eyes (19.0%). No enucleations were required during the mean follow‐up time of 192 ± 182 days. The OCT images indicated the preservation of retinal structures, while choroidal folds were only diminished in UVHA eyes. Conclusions Hyaluronic acid‐based hydrogels are biocompatible vitreous substitutes in humans and can increase and stabilize IOP in patients with phthisis bulbi for about 3 months.
    Type of Medium: Online Resource
    ISSN: 1755-375X , 1755-3768
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2023
    detail.hit.zdb_id: 2466981-7
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
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