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In Situ Formation of Injectable Gelatin Methacryloyl (GelMA) Hydrogels for Effective Intraocular Delivery of Triamcinolone Acetonide. Int J Mol Sci 2023; 24:ijms24054957. [PMID: 36902389 PMCID: PMC10003315 DOI: 10.3390/ijms24054957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Revised: 02/20/2023] [Accepted: 02/24/2023] [Indexed: 03/08/2023] Open
Abstract
A novel drug delivery system designed for intraocular injection, gelatin methacryloyl (GelMA), has attracted much attention due to its sustained-release character and low cytotoxicity. We aimed to explore the sustained drug effect of GelMA hydrogels coupled with triamcinolone acetonide (TA) after injection into the vitreous cavity. The GelMA hydrogel formulations were characterized using scanning electron microscopy, swelling measurements, biodegradation, and release studies. The biological safety effect of GelMA on human retinal pigment epithelial cells and retinal conditions was verified by in vitro and in vivo experiments. The hydrogel exhibited a low swelling ratio, resistance to enzymatic degradation, and excellent biocompatibility. The swelling properties and in vitro biodegradation characteristics were related to the gel concentration. Rapid gel formation was observed after injection, and the in vitro release study confirmed that TA-hydrogels have slower and more prolonged release kinetics than TA suspensions. In vivo fundus imaging, optical coherence tomography measurements of retinal and choroid thickness, and immunohistochemistry did not reveal any apparent abnormalities of retinal or anterior chamber angle, and ERG indicated that the hydrogel had no impact on retinal function. The GelMA hydrogel implantable intraocular device exhibited an extended duration, in situ polymerization, and support cell viability, making it an attractive, safe, and well-controlled platform for treating the posterior segment diseases of the eye.
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Soiberman U, Kambhampati SP, Wu T, Mishra MK, Oh Y, Sharma R, Wang J, Al Towerki AE, Yiu S, Stark WJ, Kannan RM. Subconjunctival injectable dendrimer-dexamethasone gel for the treatment of corneal inflammation. Biomaterials 2017; 125:38-53. [PMID: 28226245 DOI: 10.1016/j.biomaterials.2017.02.016] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2016] [Revised: 02/11/2017] [Accepted: 02/12/2017] [Indexed: 11/16/2022]
Abstract
Corneal inflammation is often encountered as a key pathological event in many corneal diseases. Current treatments involve topical corticosteroids which require frequent instillations due to rapid tear turnover, causing side-effects such as corneal toxicity and elevated intraocular pressure (IOP). Hence, new interventions that can reduce side effects, dosing frequency, and increase patient compliance can be highly beneficial. In this study, we explore a subconjunctival injectable gel based on G4-PAMAM dendrimer and hyaluronic acid, cross-linked using thiol-ene click chemistry, incorporated with dendrimer dexamethasone (D-Dex) conjugates as a potential strategy for sustained delivery and enhanced bioavailability of corticosteroids. The efficacy of the injectable gel formulation was evaluated in a rat mild alkali burn model. Fluorescently-labelled dendrimers (D-Cy5) incorporated in the gel release D-Cy5 in vivo. The released D-Cy5 selectively targets and localizes within corneal macrophages in inflamed rat cornea but not in healthy controls. This pathology dependent biodistribution was exploited for drug delivery, by incorporating D-Dex in the injectable gel. The attenuation of corneal inflammation by D-Dex gels was assessed using various clinical and biochemical parameters over a 2-week period. Subconjunctival D-Dex gel treatment resulted in favorable clinically-relevant outcomes with reduced central corneal thickness and improved corneal clarity compared to free-Dex and placebo gel controls. The extent of corneal neovascularization was significantly reduced in the D-Dex group. These findings suggest that D-Dex attenuates corneal inflammation more effectively than free-Dex by attenuating macrophage infiltration and pro-inflammatory cytokines expression. A significant elevation in IOP was not observed in the D-Dex group but was observed in the free-Dex group. This novel injectable D-Dex gel may be a potential drug delivery platform for the treatment of many inflammatory ocular surface disorders such as dry eye, auto-immune keratitis and post-surgical complications where frequent steroid administration is required.
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Affiliation(s)
- Uri Soiberman
- Center for Nanomedicine, Wilmer Eye Institute, Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Cornea Division, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Siva P Kambhampati
- Center for Nanomedicine, Wilmer Eye Institute, Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Tony Wu
- Center for Nanomedicine, Wilmer Eye Institute, Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Manoj K Mishra
- Center for Nanomedicine, Wilmer Eye Institute, Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Yumin Oh
- Center for Nanomedicine, Wilmer Eye Institute, Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Rishi Sharma
- Center for Nanomedicine, Wilmer Eye Institute, Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Jiangxia Wang
- Department of Biostatistics, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD, USA
| | | | - Samuel Yiu
- Center for Nanomedicine, Wilmer Eye Institute, Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Cornea Division, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Walter J Stark
- Center for Nanomedicine, Wilmer Eye Institute, Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Cornea Division, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
| | - Rangaramanujam M Kannan
- Center for Nanomedicine, Wilmer Eye Institute, Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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Taskar P, Tatke A, Majumdar S. Advances in the use of prodrugs for drug delivery to the eye. Expert Opin Drug Deliv 2016; 14:49-63. [PMID: 27441817 DOI: 10.1080/17425247.2016.1208649] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
INTRODUCTION Ocular drug delivery is presented with many challenges, taking into account the distinctive structure of the eye. The prodrug approach has been, and is being, employed to overcome such barriers for some drug molecules, utilizing a chemical modification approach rather than a formulation-based approach. A prodrug strategy involves modification of the active moiety into various derivatives in a fashion that imparts some advantage, such as membrane permeability, site specificity, transporter targeting and improved aqueous solubility, over the parent compound. Areas covered: The following review is a comprehensive summary of various novel methodologies and strategies reported over the past few years in the area of ocular drug delivery. Some of the strategies discussed involve polymer and lipid conjugation with the drug moiety to impart hydrophilicity or lipophilicity, or to target nutrient transporters by conjugation with transporter-specific moieties and retrometabolic drug design. Expert opinion: The application of prodrug strategies provides an option for enhancing drug penetration into the ocular tissues, and overall ocular bioavailability, with minimum disruption of the ocular diffusion barriers. Although success of the prodrug strategy is contingent on various factors, such as the chemical structure of the parent molecule, aqueous solubility and solution stability, capacity of targeted transporters and bioreversion characteristics, this approach has been successfully utilized, commercially and therapeutically, in several cases.
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Affiliation(s)
- Pranjal Taskar
- a Department of Pharmaceutics and Drug Delivery , University of Mississippi , University , MS , USA.,b Research Institute of Pharmaceutical Sciences , University of Mississippi , University , MS , USA
| | - Akshaya Tatke
- a Department of Pharmaceutics and Drug Delivery , University of Mississippi , University , MS , USA.,b Research Institute of Pharmaceutical Sciences , University of Mississippi , University , MS , USA
| | - Soumyajit Majumdar
- a Department of Pharmaceutics and Drug Delivery , University of Mississippi , University , MS , USA.,b Research Institute of Pharmaceutical Sciences , University of Mississippi , University , MS , USA
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Kambhampati SP, Mishra MK, Mastorakos P, Oh Y, Lutty GA, Kannan RM. Intracellular delivery of dendrimer triamcinolone acetonide conjugates into microglial and human retinal pigment epithelial cells. Eur J Pharm Biopharm 2015; 95:239-49. [PMID: 25701805 DOI: 10.1016/j.ejpb.2015.02.013] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2014] [Revised: 02/05/2015] [Accepted: 02/09/2015] [Indexed: 01/22/2023]
Abstract
Triamcinolone acetonide (TA) is a potent, intermediate-acting, steroid that has anti-inflammatory and anti-angiogenic activity. Intravitreal administration of TA has been used for diabetic macular edema, proliferative diabetic retinopathy and exudative age-related macular degeneration (AMD). However, the hydrophobicity, lack of solubility, and the side effects limit its effectiveness in the treatment of retinal diseases. In this study, we explore a PAMAM dendrimer-TA conjugate (D-TA) as a potential strategy to improve intracellular delivery and efficacy of TA to target cells. The conjugates were prepared with a high drug payload (∼ 21%) and were readily soluble in saline. Compared to free TA, D-TA demonstrated a significantly improved toxicity profile in two important target [microglial and human retinal pigment epithelium (RPE)] cells. The D-TA was ∼ 100-fold more effective than free TA in its anti-inflammatory activity (measured in microglia), and in suppressing VEGF production (in hypoxic RPE cells). Dendrimer-based delivery may improve the efficacy of TA towards both its key targets of inflammation and VEGF production, with significant clinical implications.
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Affiliation(s)
- Siva P Kambhampati
- Center for Nanomedicine, Wilmer Eye Institute, Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Biomedical Engineering, Wayne State University, Detroit, MI, USA
| | - Manoj K Mishra
- Center for Nanomedicine, Wilmer Eye Institute, Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Biomedical Engineering, Wayne State University, Detroit, MI, USA
| | - Panagiotis Mastorakos
- Center for Nanomedicine, Wilmer Eye Institute, Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Yumin Oh
- Center for Nanomedicine, Wilmer Eye Institute, Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Gerard A Lutty
- Center for Nanomedicine, Wilmer Eye Institute, Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Rangaramanujam M Kannan
- Center for Nanomedicine, Wilmer Eye Institute, Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Biomedical Engineering, Wayne State University, Detroit, MI, USA.
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Penha FM, Rodrigues EB, Furlani BA, Dib E, Melo GB, Farah ME. Toxicological considerations for intravitreal drugs. Expert Opin Drug Metab Toxicol 2011; 7:1021-34. [DOI: 10.1517/17425255.2011.585970] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Das N, Dhanawat M, Dash B, Nagarwal R, Shrivastava S. Codrug: An efficient approach for drug optimization. Eur J Pharm Sci 2010; 41:571-88. [DOI: 10.1016/j.ejps.2010.09.014] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2010] [Revised: 09/20/2010] [Accepted: 09/23/2010] [Indexed: 02/06/2023]
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Intraocular sustained-release delivery systems for triamcinolone acetonide. Pharm Res 2009; 26:770-84. [PMID: 19184374 DOI: 10.1007/s11095-008-9812-z] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2008] [Accepted: 12/11/2008] [Indexed: 02/06/2023]
Abstract
Recently, the use of triamcinolone acetonide (TA) injection has increased dramatically in treatment for several ocular diseases. Among them, macular diseases such as macular edema due to diabetic retinopathy, venous occlusive diseases, ocular inflammation and age-related macular degeneration (AMD) are very common vision threatening disorders and are great challenges to treat. In these types of chronic retinal diseases, repeated intraocular injections of TA are often required which increases the likelihood of complications. In order to achieve sustained-release, maintain therapeutic levels of TA over longer times and reduce frequency of intravitreal injections, researchers are investigating different implantable devices or injectable systems. However, as of yet, there is no sustained-release product for TA available on the commercial market. This review discusses and compares different sustained-release devices or injectable systems that are currently being developed.
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Yeung CK, Chiang SWY, Chan KP, Pang CP, Lam DSC. Potassium Channel Openers Reduce the Caspase-3 Expression of Triamcinolone-Treated Retinal Pigment Epithelial (ARPE19) Cells. Cutan Ocul Toxicol 2008. [DOI: 10.1080/15569520500371636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Kozak I, Cheng L, Mendez T, Davidson MC, Freeman WR. Evaluation of the toxicity of subretinal triamcinolone acetonide in the rabbit. Retina 2006; 26:811-7. [PMID: 16963856 DOI: 10.1097/01.iae.0000244255.22406.2f] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE Subretinal triamcinolone acetonide (TCA) might be a useful adjuvant in the treatment of subretinal neovascularization. The purpose of this study was to test the toxicity of subretinal TCA in the rabbit eye. METHODS Sixteen New Zealand rabbits were vitrectomized and injected with either decanted TCA solution or vehicle. The concentration of injected TCA was 2 mg, and the delivered volume was 10 microL. Rabbits were examined on days 1, 3, and 7 and then once a week up to 3 months after surgery. Optical coherence tomography was performed at months 1, 2, and 3. After the last examination, which included electroretinography, the rabbits were killed, and the eyes were enucleated for histopathologic analysis. RESULTS Subretinal TCA appeared as a white circumscribed deposit. As the drug disappeared, areas of hyperpigmentation were seen adjacent to the drug deposit. Electroretinography tracings were normal, indicating no widespread toxic effect. Histologic analysis revealed areas of absence and/or hyperpigmentation of the retinal pigment epithelium and damage to photoreceptors and the outer nuclear layer of the retina. CONCLUSION Subretinal injection of TCA crystals can be toxic to the outer retina and retinal pigment epithelium. Whether the potential beneficial effect of such a high-dose steroid in limiting subretinal inflammation, angiogenesis, and proliferation outweighs toxicity can only be determined from a clinical trial.
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Affiliation(s)
- Igor Kozak
- Jacobs Retina Center, University of California at San Diego, Shiley Eye Center, La Jolla, California 92036-0946, USA
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Jonas JB. Intravitreal triamcinolone acetonide: a change in a paradigm. Ophthalmic Res 2006; 38:218-45. [PMID: 16763379 DOI: 10.1159/000093796] [Citation(s) in RCA: 118] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2005] [Accepted: 05/09/2006] [Indexed: 12/20/2022]
Abstract
BACKGROUND Based on experimental studies and clinical observations by Robert Machemer, Gholam Peyman and others, the vitreous cavity has increasingly been used as a reservoir of drugs for the direct treatment of intraocular diseases. METHODS AND RESULTS The most widely injected drug so far has been triamcinolone acetonide for various intraocular neovascular and edematous diseases. Comparing the various diseases with respect to effect and side effects of the treatment, the best response in terms of gain in visual acuity has been achieved for intraretinal edematous diseases such as diffuse diabetic macular edema, branch retinal vein occlusion, central retinal vein occlusion, and pseudophakic cystoid macular edema. In eyes with various types of noninfectious uveitis including acute or chronic sympathetic ophthalmia and Adamantiadis-Behçet's disease, visual acuity increased and the degree of intraocular inflammation decreased. Some studies have suggested that intra- vitreal triamcinolone may be useful as an angiostatic agent in eyes with iris neovascularization and proliferative ischemic retinopathies. Intravitreal triamcinolone may possibly be helpful as adjunct therapy for exudative age-related macular degeneration, particularly in combination with photodynamic therapy. In eyes with chronic, therapy-resistant ocular hypotony, intravitreal triamcinolone can induce an increase in intraocular pressure and may stabilize the eye. The complications of intravitreal triamcinolone therapy include secondary ocular hypertension in about 40% of the eyes injected; medically uncontrollable high intraocular pressure leading to antiglaucomatous surgery in about 1-2% of the eyes; posterior subcapsular cataract and nuclear cataract leading to cataract surgery in about 15-20% in elderly patients within 1 year after injection; postoperative infectious endophthalmitis with a rate of about 1:1,000; noninfectious endophthalmitis, perhaps due to a reaction to the solvent agent, and pseudoendophthalmitis with triamcinolone acetonide crystals appearing in the anterior chamber. Intravitreal triamcinolone injection can be combined with other types of intraocular surgery including cataract surgery, particularly in eyes with iris neovascularization. Cataract surgery performed some months after the injection does not show a markedly elevated complication rate. The injection may be repeated, if vision redecreases. In nonvitrectomized eyes, the duration of the effect and side effects of a single intravitreal injection of triamcinolone is about 6-9 months for a dosage of about 20 mg, and about 2-4 months for a dosage of 4 mg. It has remained unclear so far, whether and how to remove the solvent agent. In the future, intravitreal triamcinolone may be combined with other antiangiogenic drugs for the treatment of exudative age-related macular degeneration or with neuroprotective drugs for treatment of diabetic retinopathy. CONCLUSIONS Despite an exponentially increasing number of mostly case-series studies, the intravitreal injection of triamcinolone may still be considered an experimental procedure until randomized studies have been presented.
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Affiliation(s)
- Jost B Jonas
- Department of Ophthalmology, Faculty of Clinical Medicine Mannheim, Ruprecht Karls University of Heidelberg, Heidelberg, Germany.
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Jonas JB. Intravitreal triamcinolone acetonide for treatment of intraocular oedematous and neovascular diseases. ACTA ACUST UNITED AC 2006; 83:645-63. [PMID: 16396641 DOI: 10.1111/j.1600-0420.2005.00592.x] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Intravitreal triamcinolone acetonide (IVTA) has increasingly been applied as treatment for various intraocular neovascular and oedematous diseases. Comparing the various diseases with respect to effect and side-effects of the treatment, the best response in terms of gain in visual acuity (VA) has been achieved for intraretinal oedematous diseases such as diffuse diabetic macular oedema, branch retinal vein occlusion, central retinal vein occlusion and pseudophakic cystoid macular oedema. In eyes with various types of non-infectious uveitis, including acute or chronic sympathetic ophthalmia and Adamantiadis-Behcet's disease, VA increased and the degree of intraocular inflammation decreased. Some studies have suggested that intravitreal triamcinolone may be useful as angiostatic therapy in eyes with iris neovascularization and proliferative ischaemic retinopathies. Intravitreal triamcinolone may possibly be helpful as adjunct therapy for exudative age-related macular degeneration (AMD), particularly in combination with photodynamic therapy. In eyes with chronic, therapy-resistant ocular hypotony, intravitreal triamcinolone can induce an increase in intraocular pressure (IOP) and may stabilize the eye. The complications of intravitreal triamcinolone therapy include: secondary ocular hypertension in about 40% of the eyes injected; medically uncontrollable high IOP leading to antiglaucomatous surgery in about 1-2% of the eyes; posterior subcapsular cataract and nuclear cataract leading to cataract surgery in about 15-20% of elderly patients within 1 year of injection; postoperative infectious endophthalmitis occurring at a rate of about one per 1000; non-infectious endophthalmitis, perhaps due to a reaction to the solvent agent, and pseudo-endophthalmitis with triamcinolone acetonide crystals appearing in the anterior chamber. Intravitreal triamcinolone injection can be combined with other intraocular surgeries, including cataract surgery, particularly in eyes with iris neovascularization. Cataract surgery performed some months after the injection does not show a markedly elevated complication rate. The injection may be repeated if the resultant benefits decrease after the initial IVTA injection. In non-vitrectomized eyes, the duration of the effect and side-effects of a single intravitreal injection of triamcinolone is about 6-9 months for a dosage of about 20 mg, and about 2-4 months for a dosage of 4 mg. So far, it has remained unclear whether the solvent agent should be removed, and if so, how.
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Affiliation(s)
- Jost B Jonas
- Department of Ophthalmology, Faculty of Clinical Medicine Mannheim, Ruprecht-Karls-University of Heidelberg, Germany.
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González RR, Gambarotti C, Liguori L, Bjørsvik HR. Efficient and Green Telescoped Process to 2-Methoxy-3-methyl-[1,4]benzoquinone. J Org Chem 2006; 71:1703-6. [PMID: 16468828 DOI: 10.1021/jo0522512] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A telescoped process for the preparation of 2-methoxy-3-methyl-[1,4]benzoquinone is disclosed. When this novel process is compared to the prevailing method that utilizes Na2Cr2O7 as the oxidant, the novel process represents a high yielding (95%), green, and environmentally benign alternative with H2O2 and HNO3 as the oxidants and CH3COOH as the reaction medium.
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Schuettauf F, Eibl KH, Thaler S, Shinoda K, Rejdak R, May CA, Blatsios G, Welge-Lussen U. Toxicity study of erucylphosphocholine in a rat model. Curr Eye Res 2005; 30:813-20. [PMID: 16146926 DOI: 10.1080/02713680591006093] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
PURPOSE To investigate the effect of intraocular erucylphosphocholine (ErPC) on the retina, the retinal pigment epithelium (RPE), and the choroid in an in vivo rat model. METHODS Adult male Brown Norway rats were injected intravitreally with ErPC dissolved in balanced salt solution (BSS) at a final concentration of 10 or 100 microM with BSS serving as control. Adverse effects on the anterior and posterior segment were assessed by slit-lamp biomicroscopy and ophthalmoscopy. Retinal toxicity was assessed by electroretinography (ERG), retinal ganglion cell (RGC) quantification, and histology 7 days after intravitreal administration of ErPC. RESULTS There was neither a statistically significant difference in the clinical examination nor in the ERG waves of treated versus control rats 7 days after intravitreal administration of ErPC. Correspondingly, the number of RGC after BSS injection did not differ significantly from ErPC-injected animals. Histologic sections of the posterior segment of 10 and 100 microM ErPC-injected rats did not show any signs of retinal toxicity. Electron microscopy did not display a difference between the 10 microM and the control group. Only the 100 microM-injected animals showed a discrete irregularity of the Müller cell and the retinal ganglion cell cytoplasm at the ultrastructural level. CONCLUSIONS ErPC can safely be injected into the vitreous of adult rats at a concentration of 10 microM without any retinal toxicity. Even a 10-fold increase in ErPC concentration leads only to a discrete cytoplasmic irregularity of the innermost retinal layers.
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Affiliation(s)
- Frank Schuettauf
- Department of Ophthalmology, Eberhard Karls University, Tübingen, Germany
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Jonas JB, Kreissig I, Degenring R. Intravitreal triamcinolone acetonide for treatment of intraocular proliferative, exudative, and neovascular diseases. Prog Retin Eye Res 2005; 24:587-611. [PMID: 16005407 DOI: 10.1016/j.preteyeres.2005.01.004] [Citation(s) in RCA: 122] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/31/2005] [Indexed: 01/25/2023]
Abstract
Within the last three years, triamcinolone acetonide has increasingly been applied intravitreally as treatment option for various intraocular neovascular edematous and proliferative disorders. The best response in terms of gain in visual acuity after the intravitreal injection of triamcinolone acetonide was found in eyes with intraretinal edematous diseases such as diffuse diabetic macular edema, branch retinal vein occlusion, central retinal vein occlusion, and pseudophakic cystoid macular edema. Visual acuity increased and degree of intraocular inflammation decreased in eyes with various types of non-infectious uveitis including acute or chronic sympathetic ophthalmia and Adamantiadis-Behcet's disease. Intravitreal triamcinolone may be useful as angiostatic therapy in eyes with iris neovascularization and proliferative ischemic retinopathies. Possibly, intravitreal triamcinolone may be helpful as adjunct therapy for exudative age-related macular degeneration, possibly in combination with photodynamic therapy. In eyes with chronic, therapy resistant, ocular hypotony, intravitreal triamcinolone can induce an increase in intraocular pressure and may stabilize the eye. The complications of intravitreal triamcinolone therapy include secondary ocular hypertension in about 40% of the eyes injected, cataractogenesis, postoperative infectious and non-infectious endophthalmitis, and pseudo-endophthalmitis. Intravitreal triamcinolone injection can be combined with other intraocular surgeries including cataract surgery. Cataract surgery performed some months after the injection does not show a markedly elevated rate of complications. If vision increases and eventually decreases again after an intravitreal triamcinolone acetonide injection, the injection can be repeated. The duration of the effect of a single intravitreal injection of triamcinolone depended on the dosage given. Given in a dosage of about 20mg to non-vitrectomized eyes, the duration of the effect and of the side-effects was 6-9 months. Intravitreal triamcinolone acetonide may offer a possibility for adjunctive treatment of intraocular edematous and neovascular disorders. One has to take into account the side-effects and the lack of long-term follow-up observations.
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Affiliation(s)
- Jost B Jonas
- Department of Ophthalmology, Faculty of Clinical Medicine Mannheim, Ruprecht-Karls-University of Heidelberg, Germany.
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Li H, Liu Y, Shu XZ, Gray SD, Prestwich GD. Synthesis and Biological Evaluation of a Cross-Linked Hyaluronan-Mitomycin C Hydrogel. Biomacromolecules 2004; 5:895-902. [PMID: 15132679 DOI: 10.1021/bm034463j] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A cross-linked hyaluronan (HA) hydrogel that contained a covalently bound derivative of the anti-proliferative drug mitomycin C (MMC) was synthesized and evaluated in vitro and in vivo. The HA-MMC hydrogel was prepared by coupling MMC-aziridinyl-N-acrylate with thiol-modified HA followed by cross-linking with poly(ethylene glycol) diacrylate (PEGDA). MMC was released from 0.5% and 2.0% MMC films by hydrolysis in proportion to the MMC loading. When incubated in vitro with human T31 tracheal scar fibroblasts, 0.5% MMC films inhibited proliferation, whereas 2.0% MMC films were cytotoxic. When implanted in vivo into a rat peritoneal cavity, neither 0.5% nor 2.0% HA-MMC films elicited a severe peritoneal fluid leukocyte response. Importantly, MMC reduced the thickness of fibrous tissue formed surrounding the implanted films. Thus, cross-linked HA-MMC films have strong potential as anti-fibrotic barriers for the prevention of post-surgical adhesions.
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Affiliation(s)
- Hao Li
- Department of Medicinal Chemistry, The University of Utah, 419 Wakara Way, Suite 205, Salt Lake City, Utah 84108-125, USA
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Jonas JB, Kreissig I, Kamppeter B, Degenring RF. [Intravitreal triamcinolone acetonide for the treatment of intraocular edematous and neovascular diseases]. Ophthalmologe 2004; 101:113-20. [PMID: 14991306 DOI: 10.1007/s00347-003-0982-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND Within the last 2 years, intravitreal application of triamcinolone acetonide has exponentially increased as a treatment option for various intraocular neovascular and edematous proliferative disorders. METHODS AND RESULTS The best response to intravitreal triamcinolone acetonide injection in terms of gain in visual acuity was obtained for eyes with intraretinal edematous diseases such as diffuse diabetic macular edema, branch retinal vein occlusion, central retinal vein occlusion, and pseudophakic cystoid macular edema. Visual acuity increased and degree of intraocular inflammation decreased in eyes with various types of noninfectious uveitis including sympathetic ophthalmia. Intravitreal triamcinolone may be useful as angiostatic therapy in eyes with iris neovascularization and proliferative ischemic retinopathies. Possibly, intravitreal triamcinolone may be helpful for exudative age-related macular degeneration, alone or in combination with photodynamic therapy. In eyes with chronic, therapy-resistant, ocular hypotony, intravitreal triamcinolone can induce an increase in intraocular pressure and may stabilize the eye. The complications of intravitreal triamcinolone therapy, such as secondary ocular hypertension in about 40% of the eyes injected, cataractogenesis, postoperative infectious and noninfectious endophthalmitis, and pseudo-endophthalmitis will be covered in another article. Intravitreal triamcinolone injection can be combined with other intraocular surgeries including cataract surgery. Cataract surgery performed some months after the injection did not show a markedly elevated rate of complications. If vision increases after the intravitreal triamcinolone injection, the injection can be repeated. The duration of the effect of a single intravitreal injection of triamcinolone ranges between 2 and 9 months, probably depending on the dosage used. CONCLUSIONS Intravitreal triamcinolone acetonide may offer a possibility for adjunctive treatment of intraocular oedematous and neovascular disorders. One has to take into account the side effects and the lack of long-term follow-up observations.
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Affiliation(s)
- J B Jonas
- Fakultät für Klinische Medizin Mannheim der Ruprecht-Karls-Universität, Universitäts-Augenklinik, Heidelberg.
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