Drug Delivery Challenges and Current Progress in Nanocarrier-Based Ocular Therapeutic System.

Drug instillation via a topical route is preferred since it is desirable and convenient due to the noninvasive and easy drug access to different segments of the eye for the treatment of ocular ailments. The low dose, rapid onset of action, low or no toxicity to the local tissues, and constrained systemic outreach are more prevalent in this route. The majority of ophthalmic preparations in the market are available as conventional eye drops, which rendered <5% of a drug instilled in the eye. The poor drug availability in ocular tissue may be attributed to the physiological barriers associated with the cornea, conjunctiva, lachrymal drainage, tear turnover, blood-retinal barrier, enzymatic drug degradation, and reflex action, thus impeding deeper drug penetration in the ocular cavity, including the posterior segment. The static barriers in the eye are composed of the sclera, cornea, retina, and blood-retinal barrier, whereas the dynamic barriers, referred to as the conjunctival and choroidal blood flow, tear dilution, and lymphatic clearance, critically impact the bioavailability of drugs. To circumvent such barriers, the rational design of the ocular therapeutic system indeed required enriching the drug holding time and the deeper permeation of the drug, which overall improve the bioavailability of the drug in the ocular tissue. This review provides a brief insight into the structural components of the eye as well as the therapeutic challenges and current developments in the arena of the ocular therapeutic system, based on novel drug delivery systems such as nanomicelles, nanoparticles (NPs), nanosuspensions, liposomes, in situ gel, dendrimers, contact lenses, implants, and microneedles. These nanotechnology platforms generously evolved to overwhelm the troubles associated with the physiological barriers in the ocular route. The controlled-drug-formulation-based strategic approach has considerable potential to enrich drug concentration in a specific area of the eye.

Prospective for Diagnosis and Treatment of Diabetic Retinopathy.

Diabetic retinopathy is a posterior eye disorder in which damage occurs to the light sensitive retina due to diabetes mellitus. This disorder specifically affects people aged between 18-64 with type ІІ diabetes. This disease progresses through different pathophysiological pathways, which include oxidative stress, inflammation, stimulation of the growth factor in the eye's vasculature, isoforms of protein kinase C, and also the activation of the hexosamine pathway. It starts as micro aneurysms and advances in complicated stage, which results in retinal detachment. Treatment of posterior eye diseases has complications due to the structural design of the eye and physiological barriers present. The current treatment approach involves the use of intravitreal anti- VEGFs, corticosteroids implants, laser and surgery; these treatment methods have drawbacks attributed to them despite their benefits. The development of a robust delivery system with minimal or no invasion to tackle the issues of diabetic retinopathy will be of considerable benefit to patients having diabetic retinopathy; the dependency on ophthalmologists for multiple injections will significantly reduce and provide a promising approach in drug delivery. In this review article, the authors provided information related to existing treatment methods available for diabetic retinopathy, the most significant among which is nanotechnology approach through which local delivery via the ocular route to posterior eye can be achieved. It also possesses the various carriers studied for the non-invasive approach for retinal delivery of medicaments. Non-invasive approach for delivery of drugs can be considered as potential for the treatment of diabetic retinopathy.

Processable dispersions of photocatalytically active nanosheets derived from titanium diboride: self assembly into hydrogels and paper-like macrostructures.

Titanium diboride (TiB2), a layered ceramic material, is well-known for its ultrahigh strength, wear resistance, and chemical inertness. In this work, we present a simple one-pot chemical approach that yields sheet-like nanostructures from TiB2. We serendipitously found that TiB2 crystals can undergo complete dissolution in a mild aqueous solution of H2O2 under ambient conditions. This unexpected dissolution of TiB2 is followed by non-classical recrystallization that results in nanostructures with sheet-like morphology exhibiting Ti-O and B-O functional groups. We show that this pathway can be used to obtain an aqueous dispersion of nanosheets with concentrations ≥3 mg mL-1. Interestingly, these nanosheets tend to transform into a hydrogel without the need of any additives. We found that the degree of gelation depends on the ratio of TiB2 to H2O2, which can be tuned to achieve gels with a shear modulus of 0.35 kPa. We also show this aqueous dispersion of nanosheets is processable and forms hierarchical paper-like macrostructures upon vacuum filtration. Such an ability to assemble into free-standing 3D structures would enable a leap to practical applications. We also show that the high surface area and presence of oxy-functional groups on these nanosheets endow them a superior photocatalytic activity to degrade organic pollutants. This exemplifies the rich potential that TiB2 offers upon nanoscaling. The results presented here not only add a novel material to the 2D flatland but also urge the scientific community to revisit the chemistry of metal borides, that have been traditionally considered as relatively inert ceramics.

Organogels composed of trifluoromethyl anthryl cyanostyrenes: enhanced emission and self-assembly.

A series of α-cyanostyrenes bearing anthracene and electron withdrawing trifluoromethyl units were designed and synthesized. The α-cyanostyrene skeleton favors aggregation induced enhanced emission behavior due to the restriction of intramolecular rotations. Remarkably, the anthryl cyanostyrenes bearing simple trifluoromethyl (CF3) substituents form stable organogels with enhanced fluorescence emission compared to their solution state. In water, the CF3 substituted anthrylstyrenes self-assemble into entangled fibrous nano/microstructures through intermolecular H-bonding, π-π stacking and cyano substituent interactions. The morphological features of the aggregates and the gels were substantiated using scanning electron microscopy, TEM, and powder XRD measurements. The stability of the gels was assessed using rheology investigations.

A smart approach for delivery of aripiprazole via oro-soft palatal mucosal route for improved therapeutic efficacy

Effective management of schizophrenia, acute mania, mixed episodes associated with bipolar disorders, and depression can be managed with aripiprazole moiety. In the present research work an attempt was made to minimize the dose related side effects thus improving the quality life of the patients. A novel biopolymer was isolated from the fruits of Trachyspermum ammi. Ten optimized nanosized aripiprazole loaded formulations were prepared in 1-5% concentration of biopolymer (FA1-FA5) and sodium CMC (FM1-FM5) by solvent casting technique. The formulated flexy films were evaluated for thickness, folding endurance, weight uniformity, surface pH, mucoadhesivity, In-vitro drug release studies, In-vivo pharmacodynamic study and stability studies. The isolated biopolymer showed inbuilt fimability and mucoadhesivity and consists of carbonyl, hydroxyl and thiocarbonyl functional groups. All formulations showed folding endurance from 153 to 170, mucoadhesion time in the range of 24-48hrs., and in-vitro drug release was performed using dynamic Franz Diffusion cell and analyzed using BIT-SOFTWARE. The experimental animals showed improved activity score on actophotometer. The formulated nanosized aripiprazole loaded bio-flexy films showed pharmacotherapeutic response. Conclusion can be drawn that optimized formulation showed effective Pharmacodynamic activity and can be used as for improving therapeutic efficacy of aripiprazole through this platform.