Spanlastics nanovesicular ocular insert as a novel ocular delivery of travoprost: optimization using Box-Behnken design and in vivo evaluation

Ocular mucoadhesive and biodegradable spanlastics loaded cationic spongy insert for enhancing and sustaining the anti-inflammatory effect of prednisolone Na phosphate; Preparation, I-optimal optimization, and In-vivo evaluation

This study aimed to formulate and statistically optimize spanlastics loaded spongy insert (SPLs-SI) of prednisolone Na phosphate (PRED) to enhance and sustain its anti-inflammatory effect in a controlled manner. An I-optimal optimization was employed using Design-Expert® software. The formulation variables were sonication time, the Span 60: EA ratio and type of edge activator (Tween 80 or PVA) while Entrapment efficiency (EE%), Vesicles' size (VS) and Zeta potential (ZP) were set as the dependent responses. This resulted in an optimum spanlastics (SPLs) formulation with a desirability of 0.919. It had a Span60:Tween80 ratio of 6:1 with a sonication time of 9.5 min. It was evaluated in terms of its EE%, VS, ZP, release behavior in comparison to drug solution in addition to the effect of aging on its characteristics. It had EE% of 87.56, VS of 152.2 nm and ZP of -37.38 Mv. It showed sustained release behavior of PRED in comparison to drug solution with good stability for thirty days. TEM images of the optimized PRED SPLs formulation showed spherical non-aggregated nanovesicles. Then it was loaded into chitosan spongy insert and evaluated in terms of its visual appearance, pH and mucoadhesion properties. It showed good mucoadhesive properties and pH in the safe ocular region. The FTIR, DSC and XRD spectra showed that PRED was successfully entrapped inside the SPLs vesicles. It was then exposed to an in-vivo studies where it was capable of enhancing the anti-inflammatory effect of PRED in a sustained manner with once daily application compared to commercial PRED solution. The spongy insert has the potential to be a promising carrier for the ocular delivery of PRED.

Nanomedicine in glaucoma treatment; Current challenges and future perspectives

Glaucoma presents a significant global health concern and affects millions of individuals worldwide and predicted a high increase in prevalence of about 111 million by 2040. The current standard treatment involves hypotensive eye drops; however, challenges such as patient adherence and limited drug bioavailability hinder the treatment effectiveness. Nanopharmaceuticals or nanomedicines offer promising solutions to overcome these obstacles. In this manuscript, we summarized the current limitations of conventional antiglaucoma treatment, role of nanomedicine in glaucoma treatment, rational design, factors effecting the performance of nanomedicine and different types of nanocarriers in designing of nanomedicine along with their applications in glaucoma treatment from recent literature. Current clinical challenges that hinder real-time application of antiglaucoma nanomedicine are highlighted. Lastly, future directions are identified for improving the therapeutic potential and translation of antiglaucoma nanomedicine into clinic.

Research progress of nano delivery systems for intraocular pressure lowering drugs

Glaucoma is a chronic ocular disease characterized by optic atrophy and visual field defect. The main risk factor for glaucoma onset and progression is elevated intraocular pressure, which is caused by increased aqueous humor outflow resistance. Currently, the primary method for glaucoma therapy is the use of intraocular pressure lowering drugs. However, these drugs, when administered through eye drops, have low bioavailability, require frequent administration, and often result in adverse effects. To overcome these challenges, the application of nanotechnology for drug delivery has emerged as a promising approach. Nanoparticles can physically adsorb, encapsulate, or chemically graft drugs, thereby improving their efficacy, retention time, and reducing adverse reactions. Moreover, nanotechnology has opened up new avenues for ocular administration. This article provides a comprehensive review of nano systems for intraocular pressure lowering drugs, encompassing cholinergic agonists, β-adrenergic antagonists, α-adrenergic agonists, prostaglandin analogs, carbonic anhydrase inhibitors, Rho kinase inhibitors, and complex preparations. The aim is to offer novel insights for the development of nanotechnology in the field of intraocular pressure lowering drugs.

Assembly of In-Situ Gel Containing Nano-Spanlastics of an Angiotensin II Inhibitor as a Novel Epitome for Hypertension Management: Factorial Design Optimization, In-vitro Gauging, Pharmacokinetics, and Pharmacodynamics Appraisal

More than 1 billion people worldwide suffer from hypertension; therefore, hypertension management has been categorized as a global health priority. Losartan potassium (LP) is an antihypertensive drug with a limited oral bioavailability of about 33% since it undergoes the initial metabolic cycle. Thus, nasal administration is a unique route to overcome first-pass metabolism. The investigation focused on the potential effects of LP-loaded spanlastic vesicles (SNVs) on LP pharmacodynamics and pharmacokinetic parameters, utilizing a thin-film hydration methodology established on a 3122 full factorial design. Entrapment efficiency (EE%) ranged from 39.8 ± 3.87.8 to 83.8 ± 2.92% for LP-SNVs. Vesicle size (VS) varied from 205.5 ± 6.5.10 to 445.1 ± 13.52 nm, and the percentage of LP released after 8 h (Q8h) ranged from 30.8 ± 3.10 to 68.8 ± 1.45%. LP permeated through the nasal mucosa during 24 h and flocculated from 194.1 ± 4.90 to 435.3 ± 13.53 µg/cm2. After twenty-four hours, the optimal LP-SNVs in-situ gel showed 2.35 times more permeation through the nasal mucosa than the LP solution. It also lowered systolic blood pressure, so it is thought to be better than the reference formulation in terms of pharmacodynamics. The pharmacokinetics studies demonstrated that the intranasal LP-SNVs gel boosted its bioavailability approximately 6.36 times compared to the oral LP solution. Our research showed that intranasal LP-SNVs could be a good nanoplatform because they are well-tolerated and have possible pharmacokinetics and pharmacodynamics.

Development of Carvedilol Nanoformulation-Loaded Poloxamer-Based In Situ Gel for the Management of Glaucoma

The objective of the current study was to fabricate a thermosensitive in situ gelling system for the ocular delivery of carvedilol-loaded spanlastics (CRV-SPLs). In situ gel formulations were prepared using poloxamer analogs by a cold method and was further laden with carvedilol-loaded spanlastics to boost the precorneal retention of the drug. The gelation capacity, rheological characteristics, muco-adhesion force and in vitro release of various in situ gel formulations (CS-ISGs) were studied. The optimized formula (F2) obtained at 22% w/v poloxamer 407 and 5% w/v poloxamer 188 was found to have good gelation capacity at body temperature with acceptable muco-adhesion properties, appropriate viscosity at 25 °C that would ease its ocular application, and relatively higher viscosity at 37 °C that promoted prolonged ocular residence of the formulation post eye instillation and displayed a sustained in vitro drug release pattern. Ex vivo transcorneal penetration studies through excised rabbit cornea revealed that F2 elicited a remarkable (p ˂ 0.05) improvement in CRV apparent permeation coefficient (Papp = 6.39 × 10-6 cm/s) compared to plain carvedilol-loaded in situ gel (CRV-ISG; Papp = 2.67 × 10-6 cm/s). Most importantly, in normal rabbits, the optimized formula (F2) resulted in a sustained intraocular pressure reduction and a significant enhancement in the ocular bioavailability of carvedilol, as manifested by a 2-fold increase in the AUC0-6h of CRV in the aqueous humor, compared to plain CRV-ISG formulation. To sum up, the developed thermosensitive in situ gelling system might represent a plausible carrier for ophthalmic drug delivery for better management of glaucoma.

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.

Travoprost Liquid Nanocrystals: An Innovative Armamentarium for Effective Glaucoma Therapy

To date, the ophthalmic application of liquid crystalline nanostructures (LCNs) has not been thoroughly reconnoitered, yet they have been extensively used. LCNs are primarily made up of glyceryl monooleate (GMO) or phytantriol as a lipid, a stabilizing agent, and a penetration enhancer (PE). For optimization, the D-optimal design was exploited. A characterization using TEM and XRPD was conducted. Optimized LCNs were loaded with the anti-glaucoma drug Travoprost (TRAVO). Ex vivo permeation across the cornea, in vivo pharmacokinetics, and pharmacodynamic studies were performed along with ocular tolerability examinations. Optimized LCNs are constituted of GMO, Tween® 80 as a stabilizer, and either oleic acid or Captex® 8000 as PE at 25 mg each. TRAVO-LNCs, F-1-L and F-3-L, showed particle sizes of 216.20 ± 6.12 and 129.40 ± 11.73 nm, with EE% of 85.30 ± 4.29 and 82.54 ± 7.65%, respectively, revealing the highest drug permeation parameters. The bioavailability of both attained 106.1% and 322.82%, respectively, relative to the market product TRAVATAN®. They exhibited respective intraocular pressure reductions lasting for 48 and 72 h, compared to 36 h for TRAVATAN®. All LCNs exhibited no evidence of ocular injury in comparison to the control eye. The findings revealed the competence of TRAVO-tailored LCNs in glaucoma treatment and suggested the potential application of a novel platform in ocular delivery.

Innovation in the Development of Synthetic and Natural Ocular Drug Delivery Systems for Eye Diseases Treatment: Focusing on Drug-Loaded Ocular Inserts, Contacts, and Intraocular Lenses

Nowadays, ocular drug delivery still remains a challenge, since the conventional dosage forms used for anterior and posterior ocular disease treatments, such as topical, systemic, and intraocular administration methods, present important limitations mainly related to the anatomical complexity of the eye. In particular, the blood-ocular barrier along with the corneal barrier, ocular surface, and lacrimal fluid secretion reduce the availability of the administered active compounds and their efficacy. These limitations have increased the need to develop safe and effective ocular delivery systems able to sustain the drug release in the interested ocular segment over time. In the last few years, thanks to the innovations in the materials and technologies employed, different ocular drug delivery systems have been developed. Therefore, this review aims to summarize the synthetic and natural drug-loaded ocular inserts, contacts, and intraocular lenses that have been recently developed, emphasizing the characteristics that make them promising for future ocular clinical applications.

Aqueous Prostaglandin Eye Drop Formulations

Glaucoma is one of the leading causes of irreversible blindness worldwide. It is characterized by progressive optic neuropathy in association with damage to the optic nerve head and, subsequently, visual loss if it is left untreated. Among the drug classes used for the long-term treatment of open-angle glaucoma, prostaglandin analogues (PGAs) are the first-line treatment and are available as marketed eye drop formulations for intraocular pressure (IOP) reduction by increasing the trabecular and uveoscleral outflow. PGAs have low aqueous solubility and are very unstable (i.e., hydrolysis) in aqueous solutions, which may hamper their ocular bioavailability and decrease their chemical stability. Additionally, treatment with PGA in conventional eye drops is associated with adverse effects, such as conjunctival hyperemia and trichiasis. It has been a very challenging for formulation scientists to develop stable aqueous eye drop formulations that increase the PGAs' solubility and enhance their therapeutic efficacy while simultaneously lowering their ocular side effects. Here the physiochemical properties and chemical stabilities of the commercially available PGAs are reviewed, and the compositions of their eye drop formulations are discussed. Furthermore, the novel PGA formulations for glaucoma treatment are reviewed.