Recent Insights into the Etiopathogenesis of Diabetic Retinopathy and Its Management

Formulation Advances in Posterior Segment Ocular Drug Delivery

Posterior segment ocular diseases, such as diabetic retinopathy, age-related macular degeneration, and retinal vein occlusion, are leading causes of vision impairment and blindness worldwide. Effective management of these conditions remains a formidable challenge due to the unique anatomical and physiological barriers of the eye, including the blood-retinal barrier and rapid drug clearance mechanisms. To address these hurdles, nanostructured drug delivery systems are proposed to overcome ocular barriers, target the retina, and enhance permeation while ensuring controlled release. Traditional therapeutic approaches, such as intravitreal injections, pose significant drawbacks, including patient discomfort, poor compliance, and potential complications. Therefore, understanding the physiology and clearance mechanism of eye could aid in the design of novel formulations that could be noninvasive and deliver drugs to reach the target site is pivotal for effective treatment strategies. This review focuses on recent advances in formulation strategies for posterior segment ocular drug delivery, highlighting their potential to overcome these limitations. Furthermore, the potential of nanocarrier systems such as in-situ gel, niosomes, hydrogels, dendrimers, liposomes, nanoparticles, and nanoemulsions for drug delivery more effectively and selectively is explored, and supplemented with illustrative examples, figures, and tables. This review aims to provide insights into the current state of posterior segment drug delivery, emphasizing the need for interdisciplinary approaches to develop patient-centric, minimally invasive, and effective therapeutic solutions.

Natural remedies proposed for the management of diabetic retinopathy (DR): diabetic complications

Diabetic retinopathy (DR) represents a significant and serious complication associated with diabetes mellitus (DM), often resulting in considerable visual impairment or even blindness. The intricate pathological processes underlying DR complicate the effectiveness of current treatment modalities. Studies have highlighted the potential of natural products in the treatment of DR via several beneficial effects including anti-inflammatory, antioxidant, anti-neovascular, and anti-apoptotic properties. Flavonoids, saponins, saccharides, and alkaloids exhibited various beneficial effects in DR in in vivo and in vitro studies. However, the clinical utilization of these natural compounds is hindered by issues such as inadequate specificity, low bioavailability, and potential toxicity. Therefore, there is a pressing need for rigorous clinical studies to confirm the efficacy of natural products in preventing or mitigating the progression of DR.

Exploring Endothelial Cell Dysfunction's Impact on the Brain-Retina Microenvironment Connection: Molecular Mechanisms and Implications

The intricate linking between the health of blood vessels and the functioning of neurons has attracted growing attention in the context of disorders that affect the neurological environment. Endothelial cells, forming the blood-brain barrier and blood-retinal barrier, play a fundamental role in maintaining the integrity of the brain-retina microenvironment connection. This review explores the molecular foundations of endothelial cell dysfunction and its implications for the brain-retina interaction. A comprehensive analysis of the complex factors contributing to endothelial dysfunction is presented, including oxidative stress, inflammation, reduced nitric oxide signaling, and disrupted vascular autoregulation. The significance of endothelial dysfunction extends to neurovascular coupling, synaptic plasticity, and trophic support. To our knowledge, there is currently no existing literature review addressing endothelial microvascular dysfunction and its interplay with the brain-retina microenvironment. The review also explains bidirectional communication between the brain and retina, highlighting how compromised endothelial function can disrupt this vital crosstalk and inhibit normal physiological processes. As neurodegenerative diseases frequently exhibit vascular involvement, a deeper comprehension of the interaction between endothelial cells and neural tissue holds promise for innovative therapeutic strategies. By targeting endothelial dysfunction, we may enhance our ability to preserve the intricate dynamics of the brain-retina microenvironment connection and ameliorate the progression of neurological disorders.

Correlates of retinopathy in persons living with type 2 diabetes at a clinic in Zambia

Introduction

diabetes mellitus presents a significant public health challenge globally, with its prevalence projected to rise, particularly in developing countries. Diabetic retinopathy is a common complication of diabetes and a leading cause of blindness among adults. Despite its significance, research on diabetic retinopathy in sub-Saharan Africa, including Zambia, remains limited. This study aimed to determine the prevalence of diabetic retinopathy and identify associated factors among individuals with type 2 diabetes mellitus (T2DM) attending Mahatma Gandhi Clinic in the Livingstone District of the Southern Province of Zambia.

Methods

this was a cross-sectional study, involving 48 participants aged 18 years and above, living with T2DM, and enrolled at Mahatma Gandhi Clinic in Livingstone District of Southern Province, Zambia. The primary outcome was diabetic retinopathy, which was classified using the international classification of diabetic retinopathy. Both univariate and bivariate analysis were used to estimate the prevalence of diabetic retinopathy, whereas, logistic regression was used to determine the bio-demographic, social, and clinical variables associated with diabetic retinopathy.

Results

the majority were females (n=37, 77.1%). The median age was 54 years (interquartile range (IQR) 48, 65). The mean Body Mass Index (BMI) was 27.4 (standard deviation (SD), ±6.0). The median duration of living with T2DM was 60 months (IQR, 36,132), with a mean pulse pressure of 9.6 ± 2.8 mmHg and mean glycosylated hemoglobin (HBA1C) of 9.58 ± 2.77%. Fifty percent of the participants had visual problems and hypertension (n=24 each, 50%,). Most participants reported not exercising for at least 30 minutes (n=37, 77.1 %,) and had uncontrolled sugar levels (n=32, 66.7%). Of the 48 participants, 12 (25%) had diabetic retinopathy. Longer duration of T2DM was the only factor significantly associated with diabetic retinopathy on multivariable analysis (AOR: 1.01; 95%Cl 1.00, 1.03, p<0.038).

Conclusion

this study highlights a high prevalence (25%) of diabetic retinopathy among people living with type 2 diabetes mellitus (T2DM) being managed at Mahatma Gandhi Clinic in the Livingstone District of the Southern Province of Zambia. Longer duration of living with T2DM was positively associated with diabetic retinopathy. There is a need to provide routine eye examinations in this population and increase knowledge among clients living with T2DM to reduce the burden of diabetic retinopathy in our setting.

Pharmacokinetic Analysis of Gatifloxacin and Dexamethasone in Rabbit Ocular Biofluid Using a Sensitive and Selective LC-MS/MS Method

Bacterial keratitis (BK) is an infection that causes inflammation of the cornea and, if severe, can result in blindness. Topical fluoroquinolones combined with corticosteroids have been shown to be useful in the treatment of BK. A rapid, selective, and sensitive bioanalytical method for simultaneous quantification of Gatifloxacin (GAT) and Dexamethasone (DEX) has been developed and validated using tandem mass spectrometry (LC-MS/MS). Optimal separation was accomplished in under 5 min using an Agilent Zorbax C18 column (100 mm × 4.6 mm, 3.5 μm). The mobile phase was composed of a blend of 0.2% formic acid in triple distilled water and methanol with a flow rate of 0.65 mL/min in isocratic mode. GAT and DEX were detected in positive electrospray ionization multiple reaction monitoring mode (MRM), and the retention time was found to be at 1.64 and 2.93 min, respectively. The linearity of GAT and DEX was found to be in the range of 1.56-400 ng mL-1 with good precision and accuracy. The method was validated according to USFDA regulatory guidelines. The validated method was effectively utilized for preclinical pharmacokinetic analysis of GAT and DEX in rabbit tear fluid following the topical application of a commercial formulation.

Polymers and their engineered analogues for ocular drug delivery: Enhancing therapeutic precision

Ocular drug delivery is constrained by anatomical and physiological barriers, necessitating innovative solutions for effective therapy. Natural polymers like hyaluronic acid, chitosan, and gelatin, alongside synthetic counterparts such as PLGA and PEG, have gained prominence for their biocompatibility and controlled release profiles. Recent strides in polymer conjugation strategies have enabled targeted delivery through ligand integration, facilitating tissue specificity and cellular uptake. This versatility accommodates combined drug delivery, addressing diverse anterior (e.g., glaucoma, dry eye) and posterior segment (e.g., macular degeneration, diabetic retinopathy) afflictions. The review encompasses an in-depth exploration of each natural and synthetic polymer, detailing their individual advantages and disadvantages for ocular drug delivery. By transcending ocular barriers and refining therapeutic precision, these innovations promise to reshape the management of anterior and posterior segment eye diseases.

Recent updates on ocular disease management with ophthalmic ointments

Ophthalmic diseases can result in permanent vision loss and blindness. Convenient topical and systemic treatments are preferred to address these sight-threatening conditions. However, the unique anatomy of the eye presents challenges for drug delivery. Various ophthalmic ointment formulations have been developed to enhance bioavailability in the eye to prolong residence time and improve corneal permeability. This article explores a wide range of ocular diseases affecting individuals globally and how ointments are used to manage them. From eye to ocular barriers, this review focuses on published scientific research and formulation strategies for severe ocular complications using conventional topical ointments. Additionally, it delves through patented technologies and marketed formulations supporting the use of ointments in ocular drug delivery.

Extracellular vesicles-powered immunotherapy: Unleashing the potential for safer and more effective cancer treatment

Cancer treatment has seen significant advancements with the introduction of Onco-immunotherapies (OIMTs). Although some of these therapies have received approval for use, others are either undergoing testing or are still in the early stages of development. Challenges persist in making immunotherapy widely applicable to cancer treatment. To maximize the benefits of immunotherapy and minimize potential side effects, it's essential to improve response rates across different immunotherapy methods. A promising development in this area is the use of extracellular vesicles (EVs) as novel delivery systems. These small vesicles can effectively deliver immunotherapies, enhancing their effectiveness and reducing harmful side effects. This article discusses the importance of integrating nanomedicines into OIMTs, highlighting the challenges with current anti-OIMT methods. It also explores key considerations for designing nanomedicines tailored for OIMTs, aiming to improve upon existing immunotherapy techniques. Additionally, the article looks into innovative approaches like biomimicry and the use of natural biomaterial-based nanocarriers (NCs). These advancements have the potential to transform the delivery of immunotherapy. Lastly, the article addresses the challenges of moving OIMTs from theory to clinical practice, providing insights into the future of using advanced nanotechnology in cancer treatment.

Exploring nanocarriers as innovative materials for advanced drug delivery strategies in onco-immunotherapies

In recent years, Onco-immunotherapies (OIMTs) have been shown to be a potential therapy option for cancer. Several immunotherapies have received regulatory approval, while many others are now undergoing clinical testing or are in the early stages of development. Despite this progress, a large number of challenges to the broad use of immunotherapies to treat cancer persists. To make immunotherapy more useful as a treatment while reducing its potentially harmful side effects, we need to know more about how to improve response rates to different types of immunotherapies. Nanocarriers (NCs) have the potential to harness immunotherapies efficiently, enhance the efficiency of these treatments, and reduce the severe adverse reactions that are associated with them. This article discusses the necessity to incorporate nanomedicines in OIMTs and the challenges we confront with current anti-OIMT approaches. In addition, it examines the most important considerations for building nanomedicines for OIMT, which may improve upon current immunotherapy methods. Finally, it highlights the applications and future scenarios of using nanotechnology.

Pirfenidone: A Promising Drug in Ocular Therapeutics

Pirfenidone, initially indicated for lung fibrosis, has gone beyond its original purpose, and shown promise in eye care. This detailed review tracks its evolution from lung treatment to aiding eye healing as evidenced by published literature. Pirfenidone's multifaceted attributes extend to mitigating corneal fibrosis, inflammation, and trauma. Through rigorous investigations, its efficacy emerges in diabetic retinopathy, macular degeneration, and postoperative glaucoma interventions. As an unheralded protagonist, pirfenidone reshapes ocular care paradigms, inviting renewed research opportunities.

Concurrent determination of anti-microbial and anti-inflammatory drugs in lachrymal fluid and tissue by LC-MS/MS: A potential treatment for microbial keratitis and its PK-PD evaluation

Unforeseen surfacing of microbial keratitis (MKT) over the years has led to a requisite for promising treatment strategy involving combination of antifungal and antibacterial agents. Subsequently, symptoms associated with MKT including inflammation and watery eyes require treatment with anti-inflammatory agents. Thus, a requirement of functional clinical treatment strategy involving combination of anti-inflammatory corticosteroids (Betamethasone) with antifungal polyene (Amphotericin B, AmB) and antibacterials macrolide (Azithromycin, AZT) and aminoglycoside (Neomycin, NEO). In the ensuing pursuit, a sensitive and fast simultaneous LC-MS/MS method of four drastically different analytes in rabbit tear fluid and cornea was developed and validated as per US-FDA guidelines. The gradient LC set-up was used with C18 column and flow rate of 0.55 mL/min along with short run time of 7 min. The calibration curves showed good linearity over the concentration range of 0.07-300 ng/mL, 1.00-400 ng/mL, 3.00-600 ng/mL and 8.00-900 ng/mL for AZT, AmB, NEO and BEM respectively. The bioanalytical method requires only 10 µL of ocular sample and analytes were extracted with fast protein precipitation with acidic methanol. Finally, the developed method was validated for selectivity, linearity (r2 > 0.99), precision, accuracy, matrix effects, and stability. PK-PD indices and dosing frequency was predicted using Phoenix WinNonlin Software, based on single dose ocular pharmacokinetics and MIC values of AmB, AZT and NEO. According to the PK-PD simulation, S. aureus and E. coli required 6 and 12 instillations of AZT per 24 h, respectively whereas 12 instillation of NEO requires per 24 h for S. aureus. The result suggests that to minimize antimicrobial resistance; drug, dose and dosing schedule depend upon the pathogen as well as the strain.

Ocular bioanalysis of moxifloxacin and ketorolac tromethamine in rabbit lacrimal matrix using liquid chromatography-tandem mass spectrometry

Aim: The fixed-dose combination of moxifloxacin (MOXI) and ketorolac tromethamine (KTR) is widely used for the treatment of bacterial keratitis. Thus, a new LC-MS/MS method was developed to determine MOXI and KTR in lacrimal fluid. Methods: Bioanalysis was performed using a Shimadzu 8050 LC-MS/MS in electrospray ionization-positive mode and the method was validated per US FDA guidelines. Isocratic separation was performed with a Waters Symmetry C18 column using methanol and 0.1% formic acid containing deionized water (85:15, v/v). Results & conclusion: An easy, quick and selective method was established and applied to assess the ocular pharmacokinetic profile of a commercially available formulation containing MOXI and KTR. Based on the pharmacokinetic data, this work describes pharmacokinetics-based dosage regimen calculations and their clinical significance.

Trends in Formulation Approaches for Sustained Drug Delivery to the Posterior Segment of the Eye

The eye, an intricate organ comprising physical and physiological barriers, poses a significant challenge for ophthalmic physicians seeking to treat serious ocular diseases affecting the posterior segment, such as age-related macular degeneration (AMD) and diabetic retinopathy (DR). Despite extensive efforts, the delivery of therapeutic drugs to the rear part of the eye remains an unresolved issue. This comprehensive review delves into conventional and innovative formulation strategies for drug delivery to the posterior segment of the eye. By utilizing alternative nanoformulation approaches such as liposomes, nanoparticles, and microneedle patches, researchers and clinicians can overcome the limitations of conventional eye drops and achieve more effective drug delivery to the posterior segment of the eye. These innovative strategies offer improved drug penetration, prolonged residence time, and controlled release, enhancing therapeutic outcomes for ocular diseases. Moreover, this article explores recently approved delivery systems that leverage diverse polymer technologies, such as chitosan and hyaluronic acid, to regulate drug-controlled release over an extended period. By offering a comprehensive understanding of the available formulation strategies, this review aims to empower researchers and clinicians in their pursuit of developing highly effective treatments for posterior-segment ocular diseases.