Undefined role of mucus as a barrier in ocular drug delivery

Ruponen, Marika; Urtti, Arto

doi:10.1016/j.ejpb.2015.02.032

Cited by 87 publications

(59 citation statements)

References 60 publications

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“…As ocular barrier function is not yet fully understood, 27 we assume that similar to endothelial glycocalyx barrier, conjunctival barrier function also depends on the size and charge of the particles. Since endothelial glycocalyx has negative charge, it repels negative particles and binds to cationic dyes.…”

Section: Anionic Dyes Versus Cationic Dyesmentioning

confidence: 99%

“Coffee Ring Effect” in Ophthalmology

Rajabi

Sharifzadeh²

2016

Medicine

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The process of formation of Marx line is studied in this article. Various theories have been proposed previously, in order to explain the mechanisms which lead to the development of Marx line. These theories are based on the characteristics of stained area and do not pay attention to the behavior of dye solution itself on the surface. The aim of this study is to investigate the latter behavior and introduce a new theory based on it, in order to explain the process of the Marx line formation.This study also introduces “Coffee Ring Effect” and its possible applications in explaining some ophthalmological phenomena.The effect of dye solution's behavior on the beneath surface is adopted in order to propose a novel theory. This new hypothesis is called “Anionic Dye Deposition” which was based on “Coffee Ring Effect” phenomenon. For evaluation of this theory, Evaporation pattern of Rose Bengal and fluorescein were analyzed on different surfaces. Furthermore, the effect of tear meniscus alteration on lid margin staining is studied.During the evaporation process of dye solutions, it was observed that almost all of the solute was deposited at the edge of the drop on hydrophilic surfaces. Furthermore, in the study of lid margin staining, it is observed that tear meniscus alteration during gaze affects staining pattern. This observation invalidates former hypotheses which only focus on stained surface characteristics.According to the observations in this study, it is proposed that Marx line staining occurs as a result of “anionic dye deposition” due to evaporation.

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Section: Anionic Dyes Versus Cationic Dyesmentioning

confidence: 99%

“Coffee Ring Effect” in Ophthalmology

Rajabi

Sharifzadeh²

2016

Medicine

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“…Such mechanisms include; extensive drug loss by tear dilution and high tear turnover, drainage through the nasolacrimal duct, nonproductive absorption in addition to the impermeability of the corneal epithelium which restricts the entry of foreign substances (Kompella et al, 2013, Dong et al, 2015. As a result, very low percentage of administered drug penetrates the cornea reaching the intraocular tissues thus achieving low ocular bioavailability usually ranging from 0.1-5% (Ruponen and Urtti, 2015).…”

Section: Introductionmentioning

confidence: 98%

Enhancement of lomefloxacin Hcl ocular efficacy via niosomal encapsulation: in vitro characterization and in vivo evaluation

Khalil

Abdelbary

Basha

et al. 2016

Journal of Liposome Research

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The aim of this study is to develop and evaluate niosomal dispersions loaded with the hydrophilic drug; lomefloxacin Hcl (LXN) for the management of ocular bacterial conjunctivitis. LXN-loaded niosomes were prepared by the thin film hydration method following a full factorial formulation design. Two independent variables were evaluated: the type of surfactant (X1) and the surfactant:cholesterol ratio (X2). The dependent variables comprised entrapment efficiency (EE%: Y1), particle size (PS: Y2) and zeta potential (ZP: Y3). The optimum formulation, N-LXN14 (Tw60: CH, 1:1), was spherical in shape and exhibited EE% of 68.41 ± 0.07, PS of 176.0 ± 0.98 and ZP of -40.70 ± 2.20 with a sustained release profile over 8 hours following the Higuchi model. N-LXN14 proved good physicochemical stability under refrigeration up to 3 months. Ocular irritancy test showed no signs of ocular toxicity, confirming the safety and suitability for ocular application. Microbiological evaluation of the antibacterial effect of N-LXN14 was conducted using the susceptibility test and through the induction of topical conjunctivitis by Staphylococcus aureus (S. aureus) followed by topical therapy. Susceptibility test manifested significantly higher percent inhibition of S. aureus and higher AUC of N-LXN14 (604.59 ± 0.05) compared to the commercial product (126.25 ± 0.049). Both clinical observation and colony count of the infected eyes after eight days of treatment demonstrated significant improvement in therapeutic response. The infected eyes were completely healed with eradication of S. aureus. In conclusion, the results showed that LXN niosomal dispersions may serve as a promising superior ocular delivery system in the treatment of bacterial conjunctivitis.

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“…The cornea and conjunctiva make the ocular surface. They are both covered with epithelium; additionally, mucous covers most of the outer surface of the eyeball [6]. The total surface area for the adult conjunctival sac of one eye (including the cornea) averages 16 cm 2 [7], and the corneal surface is 17-times smaller than the conjunctival surface [8].…”

Section: Eye-related Factorsmentioning

confidence: 99%

“…From the anterior chamber the drugs are removed either by aqueous humour outflow (4) or by venous blood flow after diffusing across the iris surface (5). After systemic administration drugs must pass across the retinal pigment epithelium or the retinal capillary endothelium to reach the retina and vitreous humour (6). Alternatively, drugs can be administered by intravitreal injection (7).…”

Section: Drug and Formulation-related Factorsmentioning

confidence: 99%

Drug bioavailability from topically applied ocular drops. Does drop size matter?

Jünemann

Chorągiewicz²,

Ozimek³

et al. 2016

Ophthalmology J

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The application of drops containing ocular medicines to the conjunctival sac is the most common method of drug delivery to the anterior segment of the eye. Although this route of application seemingly displays numerous advantages, obtaining effective drug concentration at its site of action is challenging. The bioavailability of a topically applied drug depends on various factors related to the eye, to the drug and formulation, to the drop, and to the patient. The present article discusses their relative significance. From a drop applied to an eye, at most 5% of a drug dose enters the ocular structures. Of utmost importance for effective ocular drug delivery are patient compliance and the physicochemical properties of the drug. For a given concentration of an active substance, drop size may determine drug adverse effects but does not influence its efficacy.

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Undefined role of mucus as a barrier in ocular drug delivery

Cited by 87 publications

References 60 publications

“Coffee Ring Effect” in Ophthalmology

“Coffee Ring Effect” in Ophthalmology

Enhancement of lomefloxacin Hcl ocular efficacy via niosomal encapsulation: in vitro characterization and in vivo evaluation

Drug bioavailability from topically applied ocular drops. Does drop size matter?

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