scholarly journals Investigation of Diffusion Characteristics through Microfluidic Channels for Passive Drug Delivery Applications

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Marcus J. Goudie ◽  
Alyssa P. Ghuman ◽  
Stephanie B. Collins ◽  
Ramana M. Pidaparti ◽  
Hitesh Handa
Keyword(s):  
Drug Delivery ◽  
Surface Chemistry ◽  
Soft Lithography ◽  
Age Related Macular Degeneration ◽  
Delivery Rate ◽  
Microfluidic Channels ◽  
Age Related ◽  
Diffusion Characteristics ◽  
Drug Delivery Applications ◽  
Model Drug

Microfluidics has many drug delivery applications due to the ability to easily create complex device designs with feature sizes reaching down to the 10s of microns. In this work, three different microchannel designs for an implantable device are investigated for treatment of ocular diseases such as glaucoma, age-related macular degeneration (AMD), and diabetic retinopathy. Devices were fabricated using polydimethylsiloxane (PDMS) and soft lithography techniques, where surface chemistry of the channels was altered using 2-[methoxy(polyethyleneoxy)propyl]trimethoxysilane (PEG-silane). An estimated delivery rate for a number of common drugs was approximated for each device through the ratio of the diffusion coefficients for the dye and the respective drug. The delivery rate of the model drugs was maintained at a physiological condition and the effects of channel design and surface chemistry on the delivery rate of the model drugs were recorded over a two-week period. Results showed that the surface chemistry of the device had no significant effect on the delivery rate of the model drugs. All designs were successful in delivering a constant daily dose for each model drug.

scholarly journals Design of an Implantable Device for Ocular Drug Delivery

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Jae-Hwan Lee ◽  
Ramana M. Pidaparti ◽  
Gary M. Atkinson ◽  
Ramana S. Moorthy
Keyword(s):  
Drug Delivery ◽  
Ocular Drug Delivery ◽  
Age Related Macular Degeneration ◽  
Ocular Diseases ◽  
Drug Management ◽  
Drug Delivery Device ◽  
Age Related ◽  
Diffusion Characteristics ◽  
Drug Reservoir ◽  
Silicon Based

Ocular diseases, such as, glaucoma, age-related macular degeneration (AMD), diabetic retinopathy, and retinitis pigmentosa require drug management in order to prevent blindness and affecting million of adults in USA and worldwide. There is an increasing need to develop devices for drug delivery to address ocular diseases. This study focuses on the design, simulation, and development of an implantable ocular drug delivery device consisting of micro-/nanochannels embedded between top and bottom covers with a drug reservoir made from polydimethylsiloxane (PDMS) which is silicon-based organic and biodegradable polymer. Several simulations were carried out with six different micro-channel configurations in order to see the feasibility for ocular drug delivery applications. Based on the results obtained, channel design of osmotic I and osmotic II satisfied the diffusion rates required for ocular drug delivery. Finally, a prototype illustrating the three components of the drug delivery design is presented. In the future, the device will be tested for its functionality and diffusion characteristics.

scholarly journals Nanoparticle-Hydrogel Composite Drug Delivery System for Potential Ocular Applications

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 642
Author(s):  
Xuan-Ling Hsu ◽  
Lien-Chen Wu ◽  
Jui-Yang Hsieh ◽  
Yi-You Huang
Keyword(s):  
Drug Delivery ◽  
Drug Delivery System ◽  
Delivery System ◽  
Drug Loading ◽  
Age Related Macular Degeneration ◽  
Intravitreal Injections ◽  
Protein Drugs ◽  
Age Related ◽  
Model Drug ◽  
Wet Amd

Intravitreal injections are clinically established procedures in the treatment of posterior eye diseases, such as wet age-related macular degeneration (wet AMD) which requires monthly intravitreal injections of anti-vascular endothelial growth factor (anti-VEGF) protein drugs that can lead to complications due to frequent dosing. In this study, we designed a composite drug delivery system (DDS) consisting of drug-loaded poly (lactide–co–glycolide) (PLGA) nanoparticles and a chemically crosslinked hyaluronan hydrogel to reduce the dosing frequency. The morphology, size, composition, and drug loading efficiency of the prepared nanoparticles were characterized. The properties of the modified hyaluronan polymers used were also examined. The degree of swelling/degradation and controlled release ability of the hyaluronan hydrogel and the composite DDS were identified using bovine serum albumin (BSA) as a model drug. The results show that this system can retain 75% of its wet weight without losing its integrity and release the model drug at the rate of 0.4 μg/day for more than two months under physiological conditions. In addition, the nanoparticulate formulation of the system can further improve bioavailability of the drugs by penetrating deep into the retinal layers. In conclusion, the proposed composite DDS is easily prepared with biocompatible materials and is promising for providing the sustained release of the protein drugs as a better treatment for ocular neovascular diseases like wet AMD.

Advanced Hydrogels Based Drug Delivery Systems for Ophthalmic Delivery

2020 ◽  
Vol 13 (4) ◽  
pp. 291-300 ◽  
Author(s):  
Srividya Gorantla ◽  
Tejashree Waghule ◽  
Vamshi Krishna Rapalli ◽  
Prem Prakash Singh ◽  
Sunil Kumar Dubey ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Drug Delivery Systems ◽  
Delivery Systems ◽  
Age Related Macular Degeneration ◽  
Stimuli Responsive ◽  
Duration Of Action ◽  
Age Related ◽  
Aqueous Gels ◽  
Ophthalmic Delivery ◽  
3D Printed

Hydrogels are aqueous gels composed of cross-linked networks of hydrophilic polymers. Stimuli-responsive based hydrogels have gained focus over the past 20 years for treating ophthalmic diseases. Different stimuli-responsive mechanisms are involved in forming polymer hydrogel networks, including change in temperature, pH, ions, and others including light, thrombin, pressure, antigen, and glucose-responsive. Incorporation of nanocarriers with these smart stimuli-responsive drug delivery systems that can extend the duration of action by increasing ocular bioavailability and reducing the dosing frequency. This review will focus on the hydrogel drug delivery systems highlighting the gelling mechanisms and emerging stimuli-responsive hydrogels from preformed gels, nanogels, and the role of advanced 3D printed hydrogels in vision-threatening diseases like age-related macular degeneration and retinitis pigmentosa. It also provides insight into the limitations of hydrogels along with the safety and biocompatibility of the hydrogel drug delivery systems.

scholarly journals Nanocarriers, Progenitor Cells, Combinational Approaches, and New Insights on the Retinal Therapy

2021 ◽  
Vol 22 (4) ◽  
pp. 1776
Author(s):  
Elham Pishavar ◽  
Hongrong Luo ◽  
Johanna Bolander ◽  
Antony Atala ◽  
Seeram Ramakrishna
Keyword(s):  
Drug Delivery ◽  
Progenitor Cells ◽  
Transfection Efficiency ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Age Related Macular Degeneration ◽  
Therapeutic Approaches ◽  
Age Related ◽  
Nanofibrous Scaffolds ◽  
The Stability

Progenitor cells derived from the retinal pigment epithelium (RPECs) have shown promise as therapeutic approaches to degenerative retinal disorders including diabetic retinopathy, age-related macular degeneration and Stargardt disease. However, the degeneration of Bruch’s membrane (BM), the natural substrate for the RPE, has been identified as one of the major limitations for utilizing RPECs. This degeneration leads to decreased support, survival and integration of the transplanted RPECs. It has been proposed that the generation of organized structures of nanofibers, in an attempt to mimic the natural retinal extracellular matrix (ECM) and its unique characteristics, could be utilized to overcome these limitations. Furthermore, nanoparticles could be incorporated to provide a platform for improved drug delivery and sustained release of molecules over several months to years. In addition, the incorporation of tissue-specific genes and stem cells into the nanostructures increased the stability and enhanced transfection efficiency of gene/drug to the posterior segment of the eye. This review discusses available drug delivery systems and combination therapies together with challenges associated with each approach. As the last step, we discuss the application of nanofibrous scaffolds for the implantation of RPE progenitor cells with the aim to enhance cell adhesion and support a functionally polarized RPE monolayer.

An Implantable Device Design Concept for Ocular Drug Delivery

2012 ◽  
Author(s):  
Jae-Hwan Lee ◽  
Ramana M. Pidaparti
Keyword(s):  
Drug Delivery ◽  
Macular Degeneration ◽  
Ocular Drug Delivery ◽  
Eye Diseases ◽  
Age Related Macular Degeneration ◽  
Intravitreal Injections ◽  
Delivery Device ◽  
Drug Delivery Device ◽  
Age Related ◽  
Intraocular Hemorrhage

New drugs for curing eye diseases have been developing for a decade and are very unique for each eye diseases such as glaucoma, cataracts, and age-related macular degeneration (AMD). It is estimated that 1.6 million adults in the US over the age of 50 and above suffer from age-related macular degeneration and about 200,000 cases are diagnosed annually. Worldwide, about 500,000 cases are diagnosed annually [1]. Drugs currently utilized for AMD are delivered via repeated intravitreal injections of the drug into the eye. Risks of repeated intravitreal injections can include intraocular infections (endophthalmitis), intraocular hemorrhage, and retinal detachment. Also, reducing the frequency of dosing will clearly benefit the patient by reducing the need for risky intravitreal injections and improving the pharmacokinetics of the drug in the eye. The eye disease of posterior segment (Dry and Wet) has limits to deliver the drug to retina region using typical eye drop. The drug injection using a needle with syringe can deliver but it barely provide right amount of doses, or over doses that may cause more severe problem such as swelling, fatigue, and damaging photoreceptor molecules. Furthermore, most drugs run away in a month so that repeated injection is necessary. Developing an implantable drug delivery device will help reduce the costs and risks associated with frequent injections and facilitate delivering the drug in a controlled manner and in the required amounts, and improve therapeutic efficacy and safety of drugs. This study focuses on the design, simulation and development of the implantable ocular drug delivery device.

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