Bimatoprost loaded microemulsion laden contact lens to treat glaucoma

Indomethacin-incorporated microemulsion-laden contact lenses for improved ocular drug delivery and therapeutic efficacy

Conventional eye drops are associated with several limitations, including rapid drug clearance and low bioavailability, with only about 5% of the administered drug reaching the cornea to demonstrate therapeutic efficacy. Thus, to address these challenges, indomethacin (IND)-loaded microemulsion (Me)-embedded soft contact lenses (CLs) were developed to improve ocular drug delivery. The D-optimal mixture design was employed to optimize the composition of the Me formulation. Independent variables included Capmul MCM (oil phase), S mix (Tween 80/isopropyl alcohol), and water, while dependent variables were the globule size, transmittance (%), and drug release profile. The optimized Me exhibited a globule diameter of 45.69 ± 1.85 nm and a transmittance of 99.4% ± 1.59%. The globule dispersion index (PDI) was 0.33 ± 0.06, and the zeta potential (ZP) was 0.657 ± 0.012 mV. Soft CLs were developed using free radical polymerization and fortified with the Me loaded with the drug through direct loading and soaking techniques. Direct loading achieved a swelling percentage of 96.37% ± 1.8% and a transmittance of 96.5% ± 0.3%, while soaking resulted in 97.57% ± 1.4% swelling and 97.3% ± 1.3% transmittance. A drug content of 19.76 ± 0.23 μg per lenses for direct loading and 29.8 ± 0.2 μg per lenses for soaking demonstrated that the efficacy of the soaking technique was higher than that of direct loading. Moreover, drug release studies showed that the Me-laden lenses prepared using the direct loading technique released 44.00% ± 0.53% to 53.00% ± 0.59% of the drug within the first 6 h, while the lenses prepared via soaking released 62.58% ± 1.56% to 97.64% ± 1.52% of the drug within the first 6 h, followed by regulated drug release for up to 28 h, maintaining clarity and drug loading. Ocular irritancy test results indicated negligible irritation, suggesting that the Me-laden lenses are a safe and effective platform to manage ocular inflammation with the controlled delivery of IND.

Drug releasing contact lenses and their application to disease presentations

Eye drops, the most common method for anterior segment treatment, face challenges of inefficiency, with less than 7% instilled drugs typically reaching target tissues of interest. The advent of contact lens drug delivery systems offers a paradigm shift, enhancing drug residence time and bioavailability on the ocular surface. This review focuses on the considerations and challenges in developing contact lenses for drug delivery, particularly for managing four categories of ocular diseases: anterior segment infections, dry eye disease, ocular allergies, and glaucoma. Each disease category requires tailored therapeutic approaches, and the technical intricacies of drug-releasing contact lenses must address concerns related to lens properties, drug release duration, and safety. The aim of this review is to provide insights into the therapeutic needs of ocular diseases and offer a comprehensive overview of the progress made in this innovative approach. The emergence of a commercially available ketotifen fumarate-releasing lens serves as a testament to the feasibility and potential benefits of this innovative approach, paving the way for further refinement and targeted applications in ocular therapeutics.

Levofloxacin-loaded silicone contact lenses materials for ocular drug delivery

Silicone contact lenses (SCL), as an emerging ocular drug delivery system, achieve controlled drug release. However, the existing drug loading methods have limitations such as low drug uptake, complicated operation process, poor welling rate and transmittance of the lens after drug loading. In this study, an effective microemulsion soaking method was proposed to increase the drug-loading capacity of silicone contact lenses. Levofloxacin (LVF) was encapsulated into the microemulsion by direct agitation, then the microemulsion was loaded into silicone contact lenses using the immersion method. The adsorption capacity of levofloxacin and its effect on drug release kinetics were explored. The results showed that the particle size of the microemulsion was approximately 160 nm. The levofloxacin microemulsion soaking method (LVF-ME-SCL) significantly enhanced the drug loading of levofloxacin in the silicone contact lenses, achieving a maximum drug loading of 216.32 ± 1.15 μg/lens (p > 0.05). The total release rate of levofloxacin was 95.96% when the sustained release time was 10 h, and the drug leakage observed after 10 h was negligible. The survival rate of E. coli and S. aureus in LVF-ME-SCL-1 (LVF concentration was 4.8 mg/mL) group was 0 and 19.33 ± 0.02% (p < 0.0001), with a significant difference, indicating that the drug-loaded silicone contact lenses exhibited effective bactericidal properties against E. coli and S. aureus. Following the addition of maximum levofloxacin, the surface contact angle of silicone contact lenses decreased significantly to 32.88 ± 1.19° (p > 0.05), while the swelling, mechanical properties, and oxygen permeability remained relatively unchanged. There was no significant decrease in the transmittance of the contact lenses after the addition of levofloxacin, which remained above 95%. In conclusion, these results show that the microemulsion impregnation method effectively improves the drug loading and sustained release time of levofloxacin, and maintains lens performance stability before and after drug loading, so it is expected to be used in ophthalmic treatment.

From Vision Correction to Drug Delivery: Unraveling the Potential of Therapeutic Contact Lens

Contact lenses (CLs) have become an essential tool in ocular drug delivery, providing effective treatment options for specific eye conditions. In recent advancements, Therapeutic CLs (TCLs) have emerged as a promising approach for maintaining therapeutic drug concentrations on the eye surface. TCLs offer unique attributes, including prolonged wear and a remarkable ability to enhance the bioavailability of loaded medications by more than 50%, thus gaining widespread usage. They have proven beneficial in pain management, medication administration, corneal healing, and protection. To achieve sustained drug delivery from TCLs, researchers are exploring diverse systems, such as polymeric nanoparticulate systems, lipidic systems, and the incorporation of agents like vitamin E or rate-limiting polymers. However, despite breakthrough successes, certain challenges persist, including ensuring drug stability during processing and manufacturing, controlling release kinetics, and biomaterial interaction, reducing protein adhesion, and addressing drug release during packaging and storage etc. While TCLs have shown overall success in treating corneal and ocular surface disorders, careful consideration of potential issues and contraindications is vital. This review offers an insightful perspective on the critical aspects that need to be addressed regarding TCLs, with a specific emphasis on their advantages and limitations.

Development of brimonidine niosomes laden contact lenses for extended release and promising delivery system in glaucoma treatment

BACKGROUND

Increased intraocular pressure is a common symptom of glaucoma. In severe circumstances, it may result in loss of eyesight. Glaucoma treatment is difficult due to ocular physiological barriers that prevent medications from reaching the afflicted area. Traditional formulations (eye drops) have a short residence period and are rapidly drained away via the nasolacrimal duct, resulting in increased adverse drug responses and lower efficacy. The usage of nanoparticles such as niosomes could be one potential answer to these problems. While niosomes improve drug penetration, they have little effect on ocular retention of the medication. Contact lenses containing niosomes can assist to overcome this disadvantage.

OBJECTIVE

This study aims to prepare and evaluate Brimonidine niosomes laden contact lenses for the treatment of Glaucoma.

METHODS

Brimonidine niosomes were prepared using thin film hydration method and evaluated. The contact lenses were soaked in the niosomal formulation at varying intervals (3-10 days). Thereafter, the contact lenses were evaluated for %transmittance, %swelling index, drug quantification and in vitro drug release. The pharmacodynamic studies were conducted to assess the reduction in intraocular pressure (IOP) in albino rabbits. The research compared the results of the reduction in intraocular pressure caused by Brimonidine niosomes laden contact lenses with a marketed preparation of niosomes.

RESULTS

Higher concentration of the drug was loaded in contact lenses loaded with Brimonidine niosomes compared to the marketed formulation, by soaking method. The contact lenses exhibited an optimal %transmittance of 98.02 ± 0.36 and %swelling index of 50.35 ± 0.57. Increase in the soaking time up to 7 days led to an increase in the drug concentration in the contact lenses. However, no further increase was observed after the 7th day due to saturation of the contact lenses. Brimonidine niosomes laden contact lenses provided a reduction in intraocular pressure that was similar to the marketed preparation. Further, the contact lenses provided extended release up to 20 h.

CONCLUSION

Brimonidine niosomes laden contact lenses exhibited superior drug loading through the soaking method, displaying optimal %transmittance and %swelling index. Soaking for 7 days increased drug concentration in contact lenses with no further increase due to saturation. These lenses reduced intraocular pressure like the marketed formulation, offering extended release for 20 h.

Recent advancements in nanomaterial-laden contact lenses for diagnosis and treatment of glaucoma, review and update

Despite the existence of numerous eye drops in the market, most of them are not sufficiently effective because of quick clearance and the barriers within the eye. To increase the delivery of the drugs to the eye, various new formulations have been explored in recent decades. These formulations aim to enhance drug retention and penetration, while enabling sustained drug release over extended periods. One such innovative approach is the utilization of contact lenses, which were originally designed for cosmetic purposes and vision correction. Contact lenses have appeared as a promising formulation for ocular drug delivery, as they can increase the bioavailability of drugs in the eye and diminish unwanted side effects. They are specifically appropriate for treating chronic eye conditions, making them an area of interest for researchers in the field of ophthalmology. This review outlines the promising potential of nanomaterial-laden contact lenses for diagnosis and treatment of glaucoma. It classifies therapeutic approaches based on nanomaterial type, summarizes diagnostic advances, discusses improvement of contact lenses properties, covers marketing perspectives, and acknowledges the challenges of these innovative contact lenses for glaucoma management.

Recent Advances of Ocular Drug Delivery Systems: Prominence of Ocular Implants for Chronic Eye Diseases

Chronic ocular diseases can seriously impact the eyes and could potentially result in blindness or serious vision loss. According to the most recent data from the WHO, there are more than 2 billion visually impaired people in the world. Therefore, it is pivotal to develop more sophisticated, long-acting drug delivery systems/devices to treat chronic eye conditions. This review covers several drug delivery nanocarriers that can control chronic eye disorders non-invasively. However, most of the developed nanocarriers are still in preclinical or clinical stages. Long-acting drug delivery systems, such as inserts and implants, constitute the majority of the clinically used methods for the treatment of chronic eye diseases due to their steady state release, persistent therapeutic activity, and ability to bypass most ocular barriers. However, implants are considered invasive drug delivery technologies, especially those that are nonbiodegradable. Furthermore, in vitro characterization approaches, although useful, are limited in mimicking or truly representing the in vivo environment. This review focuses on long-acting drug delivery systems (LADDS), particularly implantable drug delivery systems (IDDS), their formulation, methods of characterization, and clinical application for the treatment of eye diseases.

Application of Convergent Science and Technology toward Ocular Disease Treatment

Eyes are one of the main critical organs of the body that provide our brain with the most information about the surrounding environment. Disturbance in the activity of this informational organ, resulting from different ocular diseases, could affect the quality of life, so finding appropriate methods for treating ocular disease has attracted lots of attention. This is especially due to the ineffectiveness of the conventional therapeutic method to deliver drugs into the interior parts of the eye, and the also presence of barriers such as tear film, blood-ocular, and blood-retina barriers. Recently, some novel techniques, such as different types of contact lenses, micro and nanoneedles and in situ gels, have been introduced which can overcome the previously mentioned barriers. These novel techniques could enhance the bioavailability of therapeutic components inside the eyes, deliver them to the posterior side of the eyes, release them in a controlled manner, and reduce the side effects of previous methods (such as eye drops). Accordingly, this review paper aims to summarize some of the evidence on the effectiveness of these new techniques for treating ocular disease, their preclinical and clinical progression, current limitations, and future perspectives.

Advances in ophthalmic drug delivery technology for postoperative management after cataract surgery

INTRODUCTION

Cataract surgery is becoming more common due to an aging world population. Intraocular lenses and surgical technique have developed remarkably recently, but the development of postoperative medication to prevent postsurgery complications has been relatively delayed. We still largely depend on eye drops for the management of post-cataract-surgery patients. Mental and physical problems that often occur in elderly cataract patients make it difficult for patients to apply eye drops by themselves. It is necessary to develop new effective drug delivery methods.

AREAS COVERED

This updated review article provides a brief review of why drug management is needed following cataract surgery and an overview of current developments in new drug delivery methods for ophthalmic treatment. In particular, various novel drug delivery methods that can be used for post-cataract-surgery management and their current development stages are extensively reviewed.

EXPERT OPINION

Rapidly developing technologies, such as intraocular and external ophthalmic implants, polymers, and nanotechnology, are being actively applied to develop novel drug delivery systems for safe and effective management after cataract surgery. Their goal is to achieve sufficient drug release for the desired duration with a single application. These will largely replace the inconvenience of eye drops for elderly patients in the future.

Pharmaceutical, Biomedical and Ophthalmic Applications of Biodegradable Polymers (BDPs): Literature and Patent Review

In the last few decades, the interest in biodegradable materials for biomedical applications has increased significantly. Both natural and synthetic biodegradable polymers (BDPs) have been broadly explored for various biomedical applications. These include sutures and wound dressings, screws for bone fracture, scaffolds in tissue engineering, implants, and other carriers for targeted and sustained release drug delivery. Owing to their unique characteristics, including their surface charge variable copolymer block and composition and film-forming properties, BDPs have been widely used as favourable materials for ophthalmic drug delivery. Mucoadhesive BDPs have been used in ophthalmic formulations to prolong drug retention time and improve bioavailability, allowing ophthalmic controlled release systems to design. Furthermore, BDPs-based implants, microneedles, and injectable nano- and micro-particles enabled ocular posterior segment targeting and, most importantly, circumvented the need for removing the delivery systems after application. This review outlines the major advances of BDPs and highlights the latest progress of employing natural and synthetic BDPs for various biomedical applications, emphasising the treatment and management of ophthalmic conditions.

Polymeric Drug Delivery Devices: Role in Cornea and External Disease

ABSTRACT

The field of ophthalmic drug delivery is undergoing rapid changes not only in the evolution of pharmacologic agents but also in the novel drug delivery vehicles. The ocular surface has limitations to drug penetration because of the presence of tight junctions between basal epithelial cells, which limits the amount of drug that can be absorbed after topical instillation. In addition, nasolacrimal drainage reduces the precorneal residence time significantly. Contact lenses (CLs) have been considered as possible carriers for topical medications because they reside on the ocular surface for a sufficient length of time, and pharmacologic agents may be copolymerized with hydrogels allowing controlled drug diffusion. This strategy reduces the frequency of dosage while improving compliance. Modification of drug delivery vehicles is essential to allow sustained release of the drug from a polymeric complex, facilitate stability and residence time of the drug on the precorneal tear film, and improve penetration into biologic membranes. This review focuses on updates in CL-based and non-CL-based strategies in ophthalmic drug delivery.

Novel Contact Lenses Embedded with Drug-Loaded Zwitterionic Nanogels for Extended Ophthalmic Drug Delivery

Therapeutic ophthalmic contact lenses with prolonged drug release and improved bioavailability have been developed to circumvent tedious eye drop instillation. In this work, zwitterionic nanogels based on poly(sulfobetaine methacrylate) (PSBMA) were easily fabricated by one-step reflux-precipitation polymerization, with the advantages of being surfactant-free and morphology controlled. Then, the ophthalmic drug levofloxacin (LEV) was encapsulated into the nanogels. A set of contact lenses with varied nanogel-loading content was fabricated by the cast molding method, with the drug-loaded nanogels dispersed in pre-monomer solutions composed of 2-hydroxyethyl methacrylate (HEMA) and N-vinyl-2-pyrrolidone (NVP). The structure, surface morphology, water contact angle (WCA), equilibrium water content (EWC), transmittance, and mechanical properties of the contact lenses were subsequently investigated, and in vitro drug release and biocompatibility were further evaluated. As a result, the optimized contact lens with nanogel-loading content of 8 wt% could sustainably deliver LEV for ten days, with critical lens properties within the range of recommended values for commercial contact lenses. Moreover, cell viability assays revealed that the prepared contact lenses were cytocompatible, suggesting their significant potential as an alternative to traditional eye drops or ointment formulations for long-term oculopathy treatment.

Controlled bimatoprost release from graphene oxide laden contact lenses: In vitro and in vivo studies

Ocular drug delivery using contact lenses may be able to substitute for eye drop therapy. However, issues with hydrophobic drugs (like bimatoprost that is used to treat glaucoma) such as low drug uptake using a simple soaking method into preformed contact lenses and alteration in the swelling and transmittance of lenses restricts the application for drug delivery. This research uses graphene oxide (GO) to control the release of bimatoprost from contact lenses along with improvements in the drug uptake, and lens swelling and transmittance. GO was loaded into silicone hydrogel contact lenses by adding the GO at the same time as lenses were polymerized. These lenses were soaked in bimatoprost. Alternatively contact lenses, either with or without GO, were produced by adding bimatoprost during lens polymerization. GO improved contact lens swelling due to its water binding capacity and lens transmittance due to the molecular dispersion of bimatoprost on the surface of the GO which prevented the local precipitation of the drug. The bimatoprost uptake was not improved in the presence of GO. However, its in vitro release profile was improved. Adding bimatoprost and GO at the same time as lenses were polymerized (DL-GO-BMT) significantly decreased the loss of drug during extraction and sterilization in comparison to contact lenses (DL-BMT) without GO. As the amount of GO was increased, the DL-GO-BMT lenses showed a significant decrease in the burst and cumulative release of bimatoprost. Ocular irritation and histopathology reports demonstrated the safety of GO contact lens. The in vivo pharmacokinetic studies in the rabbit tear fluid showed significant improvement in mean residence time (MRT) and area under the curve (AUC) with DL-GO-0.2 μg-BMT-100 contact lens in comparison to eye drop solution. The study demonstrated that the addition of GO to contact lenses can control the release of bimatoprost as well as improved the lens swelling and transmittance. However, further optimization is needed to modulate the release of drug within the therapeutic level to manage glaucoma.

Sustained bimatoprost release using gold nanoparticles laden contact lenses

Contact lenses are ideally suited for sustained ocular drug delivery to bypass the issues associated with eye drop therapy. However, drugs such as bimatoprost loaded by the conventional soaking method show poor drug uptake, high burst release, and altered critical lens properties. In this study, the effect of gold nanoparticles (GNPs) on bimatoprost loading/uptake from the soaking solution and its release kinetics from the lens was investigated. In one method, GNP solutions of varying strength were loaded into the bimatoprost soaking solution (mM-SS batches), and in another method, the GNPs were included in the contact lens matrix during casting (mM-GN-L batches). The GNPs were spherical with average size of 21.1 nm and -20.1 mV zeta potential. The swelling, oxygen permeability, and optical transmittance of the lens were improved compared to those of the lens drug-loaded by the conventional soaking method (SM-L). The mM-GN-L batches showed significant improvement in drug uptake from the soaking solution compared to the SM-L and mM-SS batches. The in vitro studies showed relatively low burst and sustained bimatoprost release up to 72 h compared to 24 h with the SM-L batch. The ability to sustain drug release improved proportionally with an increase in the amount of GNPs in the lens. The presence of GNPs lowered protein adherence. The GNP-laden lenses were deemed safe in ocular irritation and histopathology reports (rabbit model). Further, they showed higher drug retention in the rabbit tear fluid compared to the SM-L lens. In conclusion, the presence of GNPs in contact lenses increased drug uptake from the soaking solution, and improved the in vitro and in vivo release kinetics without affecting the critical properties of the contact lenses for therapeutic application.

Contact Lenses as Ophthalmic Drug Delivery Systems: A Review

Ophthalmic drugs used for the treatment of various ocular diseases are commonly administered by eye drops. However, due to anatomical and physiological factors, there is a low bioavailability of the active principle. In order to increase the drug residence time on the cornea to adequate levels, therapeutic contact lenses have recently been proposed. The polymeric support that constitutes the contact lens is loaded with the drug; in this way, there is a direct and effective pharmacological action on the target organ, promoting a prolonged release of the active principle. The incorporation of ophthalmic drugs into contact lenses can be performed by different techniques; nowadays, the soaking method is mainly employed. To improve the therapeutic performance of drug-loaded contact lenses, innovative methods have recently been proposed, including the impregnation with supercritical carbon dioxide. This updated review of therapeutic contact lenses production and application provides useful information on the most effective preparation methodologies, recent achievements and future perspectives.

Therapeutic Ophthalmic Lenses: A Review

An increasing incidence of eye diseases has been registered in the last decades in developed countries due to the ageing of population, changes in lifestyle, environmental factors, and the presence of concomitant medical conditions. The increase of public awareness on ocular conditions leads to an early diagnosis and treatment, as well as an increased demand for more effective and minimally invasive solutions for the treatment of both the anterior and posterior segments of the eye. Despite being the most common route of ophthalmic drug administration, eye drops are associated with compliance issues, drug wastage by lacrimation, and low bioavailability due to the ocular barriers. In order to overcome these problems, the design of drug-eluting ophthalmic lenses constitutes a non-invasive and patient-friendly approach for the sustained drug delivery to the eye. Several examples of therapeutic contact lenses and intraocular lenses have been developed, by means of different strategies of drug loading, leading to promising results. This review aims to report the recent advances in the development of therapeutic ophthalmic lenses for the treatment and/or prophylaxis of eye pathologies (i.e., glaucoma, cataract, corneal diseases, or posterior segment diseases) and it gives an overview of the future perspectives and challenges in the field.

Hyaluronic acid and graphene oxide loaded silicon contact lens for corneal epithelial healing

Hyaluronic acid (HA) eye drop solution is widely used to treat and manage various corneal diseases like keratoconus (after corneal cross-linking) and dry eye syndrome. However, ocular dosage forms like eye drop solution affect the routine life style of patients due to frequent dosing schedule. In this study, HA and reduced graphene oxide (rGO) was directly loaded in the silicon contact lenses (HA-GO-DL) and compared with the conventional soaking method (HA-GO-SM). The contact lenses at lower level of rGO showed permissible swelling and transmittance properties. The water retention property of HA-GO-DL contact lenses was confirmed by water evaporation studies. The flux data of HA-GO-SM contact lenses showed high burst release with 24 h release duration. While, HA-GO-DL lenses confirmed low burst with sustained release up to 96 h. In ocular irritation study, the HA-GO-DL-2 lenses was found to be safe. The HA-GO-DL-2 batch showed high HA-tear fluid concentration (rabbit model) and improvement in the rabbit tear fluid volume (Schirmer strip studies) in comparison to the soaking method (HA-GO-SM-2) and eye drop solution. The study successfully demonstrate the potential of HA-GO loaded contact lenses to improve tear fluid volume to manage various ocular diseases like dry eye syndrome.

RETRACTED: Sustained delivery of epalrestat to the retina using PEGylated solid lipid nanoparticles laden contact lens

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editor-in-Chief. Significant similarities were noticed post-publication between this article and an article submitted to the Journal of Drug Delivery Science and Technology on the same day, by an apparently unrelated research group: Tong Zhang, Tianhui Zhu, Fanyin Wang, Ling Peng and Mingying Lai 60 (2020) 101949 https://doi.org/10.1016/j.jddst.2020.101949 Moreover, the authors did not respond to the journal request to comment on these similarities and to provide the raw data, and the Editor-in-Chief decided to retract the article. One of the conditions of submission of a paper for publication is that authors declare explicitly that their work is original and genuine. As such this article represents a severe abuse of the scientific publishing system.

Ocular Disease Therapeutics: Design and Delivery of Drugs for Diseases of the Eye

The ocular drug discovery field has evidenced significant advancement in the past decade. The FDA approvals of Rhopressa, Vyzulta, and Roclatan for glaucoma, Brolucizumab for wet age-related macular degeneration (wet AMD), Luxturna for retinitis pigmentosa, Dextenza (0.4 mg dexamethasone intracanalicular insert) for ocular inflammation, ReSure sealant to seal corneal incisions, and Lifitegrast for dry eye represent some of the major developments in the field of ocular therapeutics. A literature survey also indicates that gene therapy, stem cell therapy, and target discovery through genomic research represent significant promise as potential strategies to achieve tissue repair or regeneration and to attain therapeutic benefits in ocular diseases. Overall, the emergence of new technologies coupled with first-in-class entries in ophthalmology are highly anticipated to restructure and boost the future trends in the field of ophthalmic drug discovery. This perspective focuses on various aspects of ocular drug discovery and the recent advances therein. Recent medicinal chemistry campaigns along with a brief overview of the structure-activity relationships of the diverse chemical classes and developments in ocular drug delivery (ODD) are presented.