Retinal diseases, including age-related macular degeneration （AMD） and diabetic retinopathy （DR） are the leading causes of blindness in adults over the age of 50 years in the US. While most of those conditions do ...Retinal diseases, including age-related macular degeneration （AMD） and diabetic retinopathy （DR） are the leading causes of blindness in adults over the age of 50 years in the US. While most of those conditions do not have a cure, currently available treatment options attempt to prevent further vision loss. For many ophthalmic drugs, an efficient delivery system to provide maximum therapeutic efficacy and promote patient compliance remains an unmet medical need. An exploration of literature via PubMed spanning from 2007 to 2017 was conducted to identify studies that have evaluated nanotechnology as platforms for delivering therapeutic agents to the posterior segment of the eye where the retina is located. Until now, four routes that have been utilized for retinal drug delivery are the intravitreal, periocular, subretinal, and systemic routes. Intravitreal injections are now widely used in clinical practice due to their ability to directly target the back of the eye but are highly invasive procedures that may cause several complications, particularly with repeated uses over a short timespan. Nanotechnology shows great promise to revolutionize retinal drug delivery, offering many advantages such as a targeted delivery system towards the specific site of the retina as well as sustained delivery of therapeutic agents. In this review, specific eye anatomy and constraints on ocular drug administration are illustrated. Further, we list and highlight several examples of nanosystems, such as hydrogels, liposomes, dendrimers, and micelles, used via different drug delivery routes to treat various retinal diseases.展开更多
Based on hydromachanics and the law of conservation of energy by means of the Bernoulli Equation, the matching relation of a pump pressure and delivery, losing energy of the magma when it flows along the pipes are res...Based on hydromachanics and the law of conservation of energy by means of the Bernoulli Equation, the matching relation of a pump pressure and delivery, losing energy of the magma when it flows along the pipes are researched. This thesis provide the theoretical basis for equipment selection and selection of pipeline.展开更多
Diabetic retinopathy(DR) and age-related macular degeneration(AMD) are the leading causes of blindness in adults. The impact of these conditions on the quality of life is increasing in significance with a rise in life...Diabetic retinopathy(DR) and age-related macular degeneration(AMD) are the leading causes of blindness in adults. The impact of these conditions on the quality of life is increasing in significance with a rise in life expectancy. The role of hyperglycemia, oxidative stress and inflammatory responses in the development and/or progression of DR and AMD, and several other sight threatening ocular diseases, is well established. In proliferative retinopathy, signals sent by the retina for nourishment, triggers the growth of fragile and abnormal blood vessels. Changes in ocular pressure may lead to rupture of these blood vessels causing severe vision problems. Recent in vitro and preclinical studies demonstrate that certain phytochemicals possessing potent antioxidant and anti-inflammatory activity and ocular blood flow enhancing properties may be very useful in the treatment of, or as a prophylactic measure for, DR and AMD. Apart from these properties they have also been investigated for their anti-bacterial, hormonal, enzyme stimulation, and anti-angiogenic activities. The attractive aspect of these potential therapeutic candidates is that they can act on multiplepathways identified in the etiology of DR, AMD, cataract and other ocular diseases. However, results from clinical trials have been somewhat ambiguous, raising questions about the concentrations of these bioflavonoids achieved in the neural retina following oral administration. Unfortunately, as of date, an efficient noninvasive means to deliver therapeutic agents/candidates to the back-of-the eye is still not available. This review examines some of these promising natural agents and discusses the challenges encountered in delivering them to the posterior segment ocular tissues through the oral route.展开更多
文摘Retinal diseases, including age-related macular degeneration （AMD） and diabetic retinopathy （DR） are the leading causes of blindness in adults over the age of 50 years in the US. While most of those conditions do not have a cure, currently available treatment options attempt to prevent further vision loss. For many ophthalmic drugs, an efficient delivery system to provide maximum therapeutic efficacy and promote patient compliance remains an unmet medical need. An exploration of literature via PubMed spanning from 2007 to 2017 was conducted to identify studies that have evaluated nanotechnology as platforms for delivering therapeutic agents to the posterior segment of the eye where the retina is located. Until now, four routes that have been utilized for retinal drug delivery are the intravitreal, periocular, subretinal, and systemic routes. Intravitreal injections are now widely used in clinical practice due to their ability to directly target the back of the eye but are highly invasive procedures that may cause several complications, particularly with repeated uses over a short timespan. Nanotechnology shows great promise to revolutionize retinal drug delivery, offering many advantages such as a targeted delivery system towards the specific site of the retina as well as sustained delivery of therapeutic agents. In this review, specific eye anatomy and constraints on ocular drug administration are illustrated. Further, we list and highlight several examples of nanosystems, such as hydrogels, liposomes, dendrimers, and micelles, used via different drug delivery routes to treat various retinal diseases.
文摘Based on hydromachanics and the law of conservation of energy by means of the Bernoulli Equation, the matching relation of a pump pressure and delivery, losing energy of the magma when it flows along the pipes are researched. This thesis provide the theoretical basis for equipment selection and selection of pipeline.
文摘Diabetic retinopathy(DR) and age-related macular degeneration(AMD) are the leading causes of blindness in adults. The impact of these conditions on the quality of life is increasing in significance with a rise in life expectancy. The role of hyperglycemia, oxidative stress and inflammatory responses in the development and/or progression of DR and AMD, and several other sight threatening ocular diseases, is well established. In proliferative retinopathy, signals sent by the retina for nourishment, triggers the growth of fragile and abnormal blood vessels. Changes in ocular pressure may lead to rupture of these blood vessels causing severe vision problems. Recent in vitro and preclinical studies demonstrate that certain phytochemicals possessing potent antioxidant and anti-inflammatory activity and ocular blood flow enhancing properties may be very useful in the treatment of, or as a prophylactic measure for, DR and AMD. Apart from these properties they have also been investigated for their anti-bacterial, hormonal, enzyme stimulation, and anti-angiogenic activities. The attractive aspect of these potential therapeutic candidates is that they can act on multiplepathways identified in the etiology of DR, AMD, cataract and other ocular diseases. However, results from clinical trials have been somewhat ambiguous, raising questions about the concentrations of these bioflavonoids achieved in the neural retina following oral administration. Unfortunately, as of date, an efficient noninvasive means to deliver therapeutic agents/candidates to the back-of-the eye is still not available. This review examines some of these promising natural agents and discusses the challenges encountered in delivering them to the posterior segment ocular tissues through the oral route.
