Microemulsion: New Insights into the Ocular Drug Delivery

Abstract

Delivery of drugs into eyes using conventional drug delivery systems, such as solutions, is a considerable challenge to the treatment of ocular diseases. Drug loss from the ocular surface by lachrymal fluid secretion, lachrymal fluid-eye barriers, and blood-ocular barriers are main obstacles. A number of ophthalmic drug delivery carriers have been made to improve the bioavailability and to prolong the residence time of drugs applied topically onto the eye. The potential use of microemulsions as an ocular drug delivery carrier offers several favorable pharmaceutical and biopharmaceutical properties such as their excellent thermodynamic stability, phase transition to liquid-crystal state, very low surface tension, and small droplet size, which may result in improved ocular drug retention, extended duration of action, high ocular absorption, and permeation of loaded drugs. Further, both lipophilic and hydrophilic characteristics are present in microemulsions, so that the loaded drugs can diffuse passively as well get significantly partitioned in the variable lipophilic-hydrophilic corneal barrier. This review will provide an insight into previous studies on microemulsions for ocular delivery of drugs using various nonionic surfactants, cosurfactants, and associated irritation potential on the ocular surface. The reported in vivo experiments have shown a delayed effect of drug incorporated in microemulsion and an increase in the corneal permeation of the drug.

Development and Evaluation of a Novel Microemulsion of Dexamethasone and Tobramycin for Topical Ocular Administration

“…Generally, blue colored opalescent microemulsions are formed by this technique [93]. interfacial film lead to the formation of droplets with a smaller radius of curvature [4]. These molecules aid in the reduction of surface tension which increases the entropy thereby enhancing the thermodynamic stability of the system [103].…”

“…Long chain alcohols are proven to be more irritants than cosurfactants having shorter chains. Most commonly used cosurfactants include alkanols (ethanol, propanol, 1-butanol), alkane-diols (1,2-propane diol, 1, 2-butane diol) and alkane polyols (glycerol, glucitol) [4].…”

“…Drug delivery to the eye using microemulsions has drawn significant attention due to their intrinsic properties and ability to solubilize both hydrophilic and lipophilic drugs. They offer several advantages including thermodynamic stability combined with improved dose uniformity[3], ocular retention, permeation and absorption of drugs[4]. The present study involves the development and evaluation of a novel dexamethasone (0.1%) and tobramycin (0.3%) loaded microemulsion with potential for treating anterior segment eye inflammation and bacterial infection.Methods: The microemulsion was evaluated for pH, particle size, zeta potential, light transmittance, morphology, and in vitro drug release.…”

Continuous manufacturing of carboxyamidotriazoleencapsulated nanoemulsions using adaptive focused acoustics: Potential green technology for the pharmaceutical industry

“…Today, O/W nanoemulsions containing hydrophobic drugs are used as anesthetics, NSAID pain relievers, HIV treatments, nutritional supplements, and eye drops, with patents for several more applications filed [7,[12][13][14][15] . There is great potential for an even greater variety of pharmaceuticals as O/W nanoemulsions can be delivered via topical, enteral, and parenteral routes [6] .…”

Fundamental Aspects in the Development of Microemulsion Systems Containing Amphotericin B for Ophthalmic Use

“…The aim of this review article is, therefore, to address the main aspects of the development and preparation of microemulsions (MEs) as delivery systems for AmB through via topical ocular administration [12][13][14] .…”