View of ADVANCEMENTS IN OPHTHALMIC DRUG DELIVERY: A COMPREHENSIVE OVERVIEW

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ACCENT JOURNAL OF ECONOMICS ECOLOGY & ENGINEERING

Peer Reviewed and Refereed Journal IMPACT FACTOR: 2.104 (INTERNATIONAL JOURNAL) (ISSN NO. 2456-1037) Vol. 03, Issue 09,September 2018 Available Online: www.ajeee.co.in/index.php/AJEEE

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ADVANCEMENTS IN OPHTHALMIC DRUG DELIVERY: A COMPREHENSIVE OVERVIEW

Dr. Sumalatha Reddi

Assoc. Professor, Department of Pharmaceutical Analysis College of Pharmacy, Hyderabad, Telangana, India

Viyyapu Ramesh Naidu

Asst. Professor, Department of Pharmaceutical Analysis College of Pharmacy, Hyderabad, Telangana, India

Abstract - The eye is the body's most distinctive organ. Although a variety of drug delivery systems are used to deliver drugs into the eye, conventional systems have a number of drawbacks. As a result, researchers are looking for new ways to improve contact time, bioavailability, and residence time while also reducing patient discomfort and dose frequency. 90% of all ophthalmic formulations that are currently available are available in conventional dosage forms. The serious issue experienced is quick precorneal drug misfortune. Newer drug delivery systems for ophthalmic administration are the focus of significant research and development efforts with the goal of increasing ocular drug bioavailability. The development of systems that not only prolong the vehicle's contact time at the ocular surface but also slow the drug's elimination is the focus of recent research into ophthalmic drug delivery systems. This includes combining a number of drug delivery technologies. In this audit different new medication conveyance frameworks applied in eye like additions, in-situ gel, liposomes, niosomes, nanoparticles, iontophorosis, corneal safeguards, drug implanted contact focal points, visual wafers and movies and so on, are examined.

1 INTRODUCTION

Any active pharmaceutical ingredient in a dosage form or drug delivery system can be given to a patient via any method of administration. For the purpose of localized ophthalmic therapy, dosage forms are injected into the eye directly. The majority of ocular treatments require the application of ophthalmic active drugs topically to the tissues surrounding the ocular cavity1. When it comes to drug delivery through the eyes, there are a number of different dosage forms that can be utilized.

Eye Physiology: Figure 1 depicts the eye's cross-section. The blood supply and the eye's internal structures are both depicted. The vitreous body, lens, and cornea are all transparent media that lack blood vessels. The aqueous humor transports oxygen and nutrients to these nonvascular tissues. The oxygen tension of the aqueous humor is high, and its osmotic pressure is about the same as that of blood.

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Fig. 1 Cross section of the eye The cornea also gets some of its

oxygen from the air; if oxygen isn't available, the anaerobic metabolism causes an increase in the concentration of lactic acid within the cornea. This can cause enough edema to prevent vision for a short time and

cause the cornea to become less transparent. This could happen if a contact lens on the cornea prevents the exchange of oxygen from the air or blocks the capillary blood supply at the limbus.

Fig. 2 Section through the through the cornea A thin epithelial layer that runs

parallel to the conjunctiva at the cornea-sclerotic junction covers the cornea; The main part of the cornea is made up of collagen layers that cross each other and are surrounded on both the front and back by elastic laminae. Its posterior surface is covered by an endothelium layer.

There are a lot of free nerve endings in

the cornea. The tough, fibrous sclera, which is white and opaque, extends posteriorly from the transparent cornea. The eye's constant intra- ocular tension is able to withstand the cornea and sclera.

The four structures that make up the lachrymal apparatus constantly clean and lubricate the eye; naso-lachrymal duct, lachrymal

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3 sac, lachrymal glands, and canals At a turnover rate of 16% per minute, the lachrymal glands empty the lachrymal fluid onto the upper eyelid's conjunctiva surface. It is swept up by the blinking of the eyelids and washes over the eyeball. The lachrymal sac is compressed by the blinking reflex muscles. The sac expands when these muscles relax, pulling the lachrymal fluid into the lachrymal sacs from the lid edges along the lachrymal canals.

The fluid is then pushed down the nasal duct and into the inferior meatus of the nose by gravitational force. As a result, the lachrymal fluid keeps the eyeball from becoming dry and inflamed by constantly irrigating it. How much lachrymal liquid restored by the incessant compulsory squinting developments typically is only adequate to stay up with its vanishing from conjunctiva.

Lacrimation, or an excessive production and secretion of lachrymal fluid, can, on the other hand, occur when emotional stress, bright light is shined into the eye, or foreign objects or other irritants enter the eye.

2 VISCOSITY AND OCULAR RESIDENCE

Maintaining acuity is a physiological requirement, which makes it difficult to maintain drug concentrations for long periods of time. This is especially true when it comes to providing a transparent formulation, reducing irritation, and avoiding rapid clearance. Constitution or solvency contemplations limit the grouping of the dynamic to around 2% w/v which likens to a greatest portion of around 500-600 μg in a solitary drop 10.

Particulates and ointments can be used to expose the pericorneal area more, but emulsion formulations offer

a variety of benefits. If a drug has a high affinity for the oil phase, for instance, in a micro emulsion, it is likely to be cleared before sufficient time has passed for partition from the vehicle to the tissue. Consequently, the depot release is low, though the oil-based formulation may have significant persistence.

3 CONCLUSION AND FUTURE SCOPE

Nanocarrier-based ocular drug delivery technology based on the use of nanoparticles, liposomes, and dendrimers has recently been investigated with the goal of improving frontal ocular drug delivery. It is claimed that these systems have a longer residence time at the ocular surface, minimizing the impact of the body's own natural mechanisms for clearing the eye.

It has been contended that, when joined with controlled drug conveyance, giving medication remedial levels to a delayed time at the site of action ought to be conceivable. In a number of excellent books, the use of nanoparticles and other ocular drug delivery methods has been discussed; The research in this area will undoubtedly gain momentum in the future as well.

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