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Ashton, Paul; Podder, Samir Kumar; Lee, Vincent H.L.

doi:10.1023/a:1015810619869

Cited by 51 publications

(6 citation statements)

References 10 publications

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“…The first process in this route following ophthalmic administration is conjunctival penetration. In the in vitro studies described above, the effect of pH on the conjunctival penetration was less than that on corneal penetration, which is the first process of the uveal route [17, 18]. However, our results show that the difference in AUC 0–360 between the two ophthalmic solutions in the posterior retina/choroid was less than that in anterior retina/choroid, which seem to be inconsistent with the in vitro results.…”

Section: Discussioncontrasting

confidence: 87%

“…The first step in the process in all three routes involves penetration of either the cornea or conjunctiva, and it is surmised that the solution pH particularly influences this process. In vitro permeability studies have shown that the pH affects corneal penetration more than conjunctival penetration [17, 18]. In the present study, the AUC 0–360 ratio of the two ophthalmic solutions in the anterior retina/choroid was comparable to the estimated ratio in the aqueous humor.…”

Section: Discussionsupporting

confidence: 72%

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Effect of Solution pH on Distribution of Ophthalmically Administered Brimonidine in Posterior Ocular Tissues in Pigmented Rabbits

et al. 2019

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Introduction Brimonidine bioavailability in the aqueous humor depends on the solution pH following topical administration. The purpose of this study was to investigate the effect of solution pH on brimonidine distribution in the posterior ocular tissues in pigmented rabbits. Methods The anterior retina/choroid, posterior retina/choroid, and vitreous body of pigmented rabbits were collected 0.67, 1.5, 3, 6, 12, 24, 168, and 360 h after the administration of a single topical dose of 0.2% brimonidine tartrate ophthalmic solution, pH 6.4 (Alphagan ® ; Allergan Inc., Irvine, CA, USA). Brimonidine concentrations in these tissues were quantified using liquid chromatography/tandem mass spectrometry. Pharmacokinetic parameters were determined using noncompartmental analysis, and the results were compared with tissues from eyes administered 0.1% brimonidine tartrate ophthalmic solution, pH 7.3 (Aiphagan ® ; Senju Pharmaceutical Co., Ltd., Osaka, Japan) in our previous study conducted using the same procedure. Results Topically applied brimonidine was distributed rapidly into the posterior tissues of the eye after a single ophthalmic administration of the 0.2% ophthalmic solution. The areas under the curve from time 0 to 360 h following dosing with the 0.2% ophthalmic solution were 500,000, 14,300, and 28.7 ng h/g in the anterior and posterior retina/choroid, and vitreous body, respectively. Conclusion The differences in the areas under the curve between two ophthalmic solutions were less than the difference in drug concentrations between these two products in any tissues. This finding indicates that the change in the solution pH from 6.4 to 7.3 increases brimonidine bioavailability into the posterior ocular tissues similarly as into the aqueous humor. Funding Senju Pharmaceutical Co., Ltd.

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Section: Discussioncontrasting

confidence: 87%

Section: Discussionsupporting

confidence: 72%

Effect of Solution pH on Distribution of Ophthalmically Administered Brimonidine in Posterior Ocular Tissues in Pigmented Rabbits

et al. 2019

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“…1c ) is that the TM is actually more lipophilic than TB. The reported value of the octanol/water partition coefficient for TB is 2.4 [ 19 ], while that for TM is about 60 [ 20 ]. This being the case, we used the more lipophilic TM for the rest of the studies.…”

Section: Resultsmentioning

confidence: 99%

A biodegradable ocular implant for long-term suppression of intraocular pressure

Liu

Veluchamy

et al. 2015

Drug Deliv. and Transl. Res.

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Timolol maleate (TM) has been used for many years for the reduction of intraocular pressure (IOP) in glaucoma patients. However, the topical mode of administration (eyedrops) is far from optimal because of the issues of low bioavailability, high drug wastage, and lack of patient compliance. Suboptimal control of the IOP leads to disease progression and eventually to blindness. Ideally, TM is delivered to the patient so that its action is both localized and sustained for 3 months or more. In this work, we developed a subconjunctival TM microfilm for sustained, long-term delivery of TM to the eyes, using the biodegradable elastomer poly(lactide-co-caprolactone) (PLC). The copolymer is biocompatible and has flexibility and mechanical characteristics suitable for a patient-acceptable implant. Controlling the release of TM for 3 months is challenging, and this work describes how, by using a combination of multilayering and blending with poly(ethylene glycol) (PEG) copolymers, we were able to develop a TM-incorporated biodegradable film that can deliver TM at a therapeutic dose for 90 days in vitro. The data was further confirmed in a diseased primate model, with sustained IOP-lowering effects for 5 months with a single implant, with acceptable biocompatibility and partial degradation.

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“…To increase its penetration, it is necessary to relax the intercellular junctions of the corneal epithelium, which is possible through the use of BAK, used for decades in ophthalmic preparations as “drug penetration enhancer.”[1617]…”

Section: Discussionmentioning

confidence: 99%

A preliminary study of the neuroprotective role of citicoline eye drops in glaucomatous optic neuropathy

Roberti

Tanga

Parisi

et al. 2014

Indian J Ophthalmol

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Purpose:To study the neuroprotective effect of topical citicoline.Materials and Methods:Experimental phase to evaluate the ability of citicoline eye drops to reach the vitreous and the retina: The right eyes of 5 mice CD1 were treated with two drops per day for three days of citicoline 1% and 2% (OMK1, Omikron Italia s.r.l.), and then the vitreous was analyzed with the liquid chromatography and spectrometry mass (LC-MS/MS). Clinical phase to determine if topical citicoline is able to delay glaucoma progression, considering perimetric parameters and electro functional tests. Patients were randomized in two groups, OMK1 and OAG. The first group was treated with OMK1 three times per day, plus hypotensive therapy for two months and one month of wash out. The second group was treated only with hypotensive treatment for three months.Results:LC-MS/MS detected the molecule very well, and only OMK1 showed systemic absorption. Thirty-four patients were enrolled, 16 in the OMK1 and 18 in the OAG group. Perimetric parameters showed a positive trend in individual eyes of patients in OMK1 group, but these values were not statistically significant in the whole group. Retinal ganglion cells function improved as shown by reduced P50 latency (P = 0.04) and increased P50-N95 amplitude (P < 0.0001) of pattern electroretinogram, up to 30 days after the washout (P = 0.01; P = 0.002). Visual evoked potential and retino-cortical time improvement regressed after 30 days of washout. In OAG group, there was any change during the follow-up. No adverse reactions were reported in both groups.Conclusions:Topical citicoline seems to have a neuroprotective action.

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Untitled

Cited by 51 publications

References 10 publications

Effect of Solution pH on Distribution of Ophthalmically Administered Brimonidine in Posterior Ocular Tissues in Pigmented Rabbits

Effect of Solution pH on Distribution of Ophthalmically Administered Brimonidine in Posterior Ocular Tissues in Pigmented Rabbits

A biodegradable ocular implant for long-term suppression of intraocular pressure

A preliminary study of the neuroprotective role of citicoline eye drops in glaucomatous optic neuropathy

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