Mucoadhesive niosomalin situgel for ocular tissue targeting:in vitroandin vivoevaluation of lomefloxacin hydrochloride

Abstract

Eradication of ophthalmic infections depends on increasing transcorneal permeation and localizing antibiotics at ocular surface. This study aimed at formulating lomefloxacin HCl (LF) in the form of niosomes and evaluating the in vivo performance of best formula in rabbits' eyes. Vesicles were developed by mixing three surfactants at three molar ratios of 1:1, 1:2 and 1:3 of surfactant to cholesterol. Size, zeta potential, release percentage, transcorneal permeation parameters, stability studies, cytotoxicity and antibacterial activity of niosomes were determined. Niosomes showed encapsulation efficiency of more than 78%, particle size below 500 nm and zeta potential below -43.6. The produced vesicles showed significantly higher amounts of drug permeated across cornea (166%) compared to LF solution. The in vivo study showed 2-5 folds increase in drug concentration in ocular fluids and tissues following administration of niosomes compared to marketed formula (from 3.75 to 10.31 mcg/mL in the cornea). Microbiological studies showed 35 folds increase in the antibacterial activity of LF niosomes compared to free drug; where MBC decreased from 31.25 mcg/mL in case of LF solution to 0.97 mcg/mL for niosomal gel. The formulated niosomes enhanced the ocular bioavailability of LF through increasing transcorneal permeation and localizing drug at site of action.

Vancomycin-loaded niosomes integrated within pH-sensitive in-situ forming gel for treatment of ocular infections while minimizing drug irritation

“…Furthermore, non‐ionic surfactant vesicles (i.e. niosomes) have been exploited for ocular drug delivery to improve permeability and bioavailability of drugs and to achieve localized drug action since their sizes and low penetrability through epithelium maintain the drug localized at the site of administration and increase precorneal residence time . A further significant increase in the precorneal residence time and bioavailability of drugs can be achieved via utilizing viscous/semisolid delivery systems, such as creams, ointments and gels.…”

“…niosomes) have been exploited for ocular drug delivery to improve permeability and bioavailability of drugs and to achieve localized drug action since their sizes and low penetrability through epithelium maintain the drug localized at the site of administration and increase precorneal residence time. [11][12][13] A further significant increase in the precorneal residence time and bioavailability of drugs can be achieved via utilizing viscous/semisolid delivery systems, such as creams, ointments and gels. In one study, vancomycin was administered as a 1% ophthalmic ointment for treatment of ocular MRSA and methicillin-resistant Staphylococcus epidermidis infections and resulted in high antibacterial efficacy.…”

Intranasal niosomes of nefopam with improved bioavailability: preparation, optimization, and in-vivo evaluation

“…Moreover, the lower EE% of Span 80 can be attributed to its transition temperature as it has the lowest transition temperature among the used Spans. 12 , 32…”

“…NF-loaded niosomes were isolated from free NF by centrifugation 12 at 24,000 rpm for 1 hour (Sigma cooling centrifuge, 3-30 K, Sigma-Elektro, Neustadt an der Wein-strasse, Germany). The pellets were removed, washed twice, and recentrifuged for accuracy.…”

“…Niosomes are core–shell systems in which the shell is composed of nonionic surfactants along with stabilizers like cholesterol while the core is usually aqueous. 12 Considering nasal delivery, niosomes could be the vesicular system of choice due to 1) their chemical and physical stabilities, which are higher than those of liposomes; 2) their ability to carry both lipo-philic and hydrophilic drugs; 3) their nonionic nature, which contributes to their low toxicity; 4) their high permeability through biological membranes; and 5) their biodegradable nature, which contributes to their easy removal from body. 13 There are a few reports on formulating NF as advanced drug delivery systems.…”