Mathematical Model of Macromolecular Drug Transport in a Partially Liquefied Vitreous Humor

The purpose of this study is to investigate the effect of partial liquefaction (due to ageing) of the vitreous humor on the transport of ocular drugs. In our model, the gel part of the vitreous is treated as a Darcy-type porous medium. A spherical region within the porous part of vitreous is in a liquid state which, for computational purposes, is also treated as a porous medium but with a much higher permeability. Using the finite element method, a time-dependent, three-dimensional model has been developed to computationally simulate (using the Petrov-Galerkin method) the transport of intravitreally injected macromolecules where both convection and diffusion are present. From a fluid physics and transport phenomena perspective, the results show many interesting features. For pressure-driven flow across the vitreous, the flow streamlines converge into the liquefied region as the flow seeks the fastest path of travel. Furthermore, as expected, with increased level of liquefaction, the overall flow rate increases for a given pressure drop. We have quantified this effect for various geometrical considerations. The flow convergence into the liquefied region has important implication for convective transport. One effect is the clear diversion of the drug as it reaches the liquefied region. In some instances, the entry point of the drug in the retinal region gets slightly shifted due to liquefaction. While the model has many approximations and assumptions, the focus is illustrating the effect of liquefaction as one of the building blocks towards a fully comprehensive model.

MULTIDISCIPLINARY APPROACH IN THE PREVENTION AND MANAGEMENT OF OCULAR HEALTH

In today’s era of globalization, prevention plays an important role in the field of health science. Excess us-age of gadgets like use of computers, ipads and smart phones is leading to over functioning of eyes. Eyes are the windows to the mind. among the five sense organs Ayurveda gives prime importance to eyes. Now-a-days changed work expectations requiring prolonged working hours in front of computers, nutritional deficiency, pollution, stress, indiscriminate use of topical ocular drugs and increased incidence of allergic disorders, etc. lead to eye diseases. Suffering from ocular disorders with uncorrected refractive error in children result into adverse effect on quality of life and significantly affect their vision, education and psy-chosocial development. Working in artificial light either dim light or bright light is another culprit for dete-rioration of ocular health so emphasis should be laid on the prevention of these, as eyes are the most im-portant and sensitive of five sense organs in human body. Ayurveda is one of the greatest gifts to mankind. In Ayurveda, selected classical daily regimes like Netraprakshalana (eye wash), Anjana (collyrium), Snana(bath), Padabhyanga (foot massage with oil), Nasya (nasal application of drugs), wholesome and unwholesome dietetics are promoted as high-end measures for the maintenance of eye-health. Various Netravyayamas (eye exercises), Yogasanas, Pranayamas, Neti and Trataka are said to be beneficial for the same cause. The main aim of this review is to promote and spread the awareness about maintenance of oc-ular health and prevention from the earlier causation of ocular diseases.

Peptidomimetics Therapeutics for Retinal Disease

Ocular disorders originating in the retina can result in a partial or total loss of vision, making drug delivery to the retina of vital importance. However, effectively delivering drugs to the retina remains a challenge for ophthalmologists due to various anatomical and physicochemical barriers in the eye. This review introduces diverse administration routes and the accordant pharmacokinetic profiles of ocular drugs to aid in the development of safe and efficient drug delivery systems to the retina with a focus on peptidomimetics as a growing class of retinal drugs, which have great therapeutic potential and a high degree of specificity. We also discuss the pharmacokinetic profiles of small molecule drugs due to their structural similarity to small peptidomimetics. Lastly, various formulation strategies are suggested to overcome pharmacokinetic hurdles such as solubility, retention time, enzymatic degradation, tissue targeting, and membrane permeability. This knowledge can be used to help design ocular delivery platforms for peptidomimetics, not only for the treatment of various retinal diseases, but also for the selection of potential peptidomimetic drug targets.

Using subpalpebral lavage systems to deliver ocular drugs to 4 fractious dogs

The use of subpalpebral lavage systems is commonplace in equine ophthalmology and its use has also been described in humans, llamas and a harbour seal. However, reports of this drug delivery technique in dogs are lacking. This case study describes four cases of corneal ulceration in fractious dogs, where a subpalpebral lavage system was used to apply topical medication. Clinical presentation, surgical techniques and the outcomes are described. All dogs were successfully treated by their owners using this technique, and no major complications were reported.

Trend in the use of topical ocular anti-infectives in a region of Spain between 2015 and 2019: a population-based registry study

Objectives. This study presents the use and trends of use of topical ocular anti-infectives into a European population in the current decade (2015 to 2019) with an analysis of concomitant use with other ocular drugs, considering distribution by age and gender. Patients and Methods. A population-based registry study was carried out to assess the ocular anti-infectives use from 2015 to 2019. All dispensations of these medicines at pharmacies in the largest region of Spain, Castile and León, was accessed. The number of packages dispensed, the percentage of the population under treatment, diagnosis, and the concomitant use with other ocular medicines was observed. For all analyses, the population distribution by age and gender was considered. Results. An average of 198,000 packages of topical ocular anti-infectives were dispensed annually to 5.38% of the population, and more commonly for women than for men (5.83% vs. 4.91%). Children and the elderly used more these medicines. Tobramycin, alone or in combination, accounted for more than 68% of the total consumption (135,000 packages per year), and was the most widely used anti-infective in almost all identified diagnoses. Conjunctivitis (50.12%), and stye (11.51%) were the most frequent diagnoses. The consumption of ocular anti-infectives increased by 8.23% from 2015 to 2019, and more among men than in women. Conclusions. Our findings show that the most used topical ocular anti-infective was tobramycin, in accordance with the clinical practice guidelines recommendations. However, ocular infections are sometimes treated empirically, especially conjunctivitis.

Amphiphilic Acrylic Nanoparticles Containing the Poloxamer Star Bayfit® 10WF15 as Ophthalmic Drug Carriers

Topical application of drops containing ocular drugs is the preferred non-invasive route to treat diseases that affect the anterior segment of the eye. However, the formulation of eye drops is a major challenge for pharmacists since the access of drugs to ocular tissues is restricted by several barriers. Acetazolamide (ACZ) is a carbonic anhydrase inhibitor used orally for the treatment of ocular hypertension in glaucoma. However, large ACZ doses are needed which results in systemic side effects. Recently, we synthesized copolymers based on 2-hydroxyethyl methacrylate (HEMA) and a functionalized three-arm poloxamer star (Bayfit-MA). The new material (HEMA/Bayfit-MA) was engineered to be transformed into nanoparticles without the use of surfactants, which represents a significant step forward in developing new ophthalmic drug delivery platforms. Acetazolamide-loaded nanocarriers (ACZ-NPs) were prepared via dialysis (224 ± 19 nm, −17.2 ± 0.4 mV). The in vitro release rate of ACZ was constant over 24 h (cumulative delivery of ACZ: 83.3 ± 8.4%). Following standard specifications, ACZ-NPs were not cytotoxic in vitro in cornea, conjunctiva, and macrophages. In normotensive rabbits, ACZ-NPs generated a significant intraocular pressure reduction compared to a conventional solution of ACZ (16.4% versus 9.6%) with the same dose of the hypotensive drug (20 µg). In comparison to previously reported studies, this formulation reduced intraocular pressure with a lower dose of ACZ. In summary, HEMA:Bayfit-MA nanoparticles may be a promising system for ocular topical treatments, showing an enhanced ocular bioavailability of ACZ after a single instillation on the ocular surface.