Passage of drugs through different intraocular microdialysis membranes

Waga, Janina; Ehinger, Berndt

doi:10.1007/bf00177783

Cited by 21 publications

(16 citation statements)

References 18 publications

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“…With microdialysis the administration can be repeated several times as long as the intraocular membrane functions. In previous experiments with chronically implanted intraocular probes, the membranes regularly stayed functional for 3 weeks or more (Waga et al 1991;Waga & Ehinger 1995). Other investigators using removable intraocular microdialysis probes repeatedly introduced through a scleral port, report no complications for up to 6 months (Stempels et al 1993).…”

Section: Discussionmentioning

confidence: 84%

“…The reason for this was to compare the measured concentration in the buffer with the concentration in the vitreous after an in vivo perfusion. For the in vivo experiments, a microdialysis probe with a 6 mm PES membrane bent for ocular use (Waga & Ehinger 1995) was implanted into the vitreous of both eyes of anesthetized pigmented rabbits. M. In the latter case the labeled NGF was used as a tracer mixed with an unlabeled carrier (Sigma).…”

Section: Methodsmentioning

confidence: 99%

“…The method was originally developed for transmitter studies in the CNS (Ungerstedt et al 1984 ) and has been adapted for ocular use (Waga et al 1991, Waga & Ehinger 1995. It is particularly well suited for administration and/or withdrawal of diffusible substances from the vitreous, as it permits the molecules to pass through the intraocular membrane without any net fluid movement in or out of the eye.…”

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confidence: 99%

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NGF administered by microdialysis into rabbit vitreous

Waga

Ehinger

2000

Acta Ophthalmologica Scandinavica

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ABSTRACT.Purpose: Microdialysis has been used in eye research for almost a decade. We have previously developed and used it mainly for chronic experiments and here it is used in acute experiments. It is highly suitable for both administration and withdrawal of substances from the eye, as it only permits molecules to cross the intraocular membrane without any net fluid movement in or out of the eye. Methods: We have here investigated the ability of 125 I labeled NGF (nerve growth factor) to cross a previously implanted high permeability membrane of a new type (polyether sulphone, PES, cutoff at 100 000 daltons) in the rabbit vitreous. It was perfused for different time periods with a solution containing NGF. The radioactivity of the entire vitreous was then counted. Results:The results show detectable levels (up to 10 ª11 M) of the substance after the perfusions. Conclusion: We conclude that microdialysis with PES membranes is a possible method for the intraocular administration of NGF.

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Section: Discussionmentioning

confidence: 84%

Section: Methodsmentioning

confidence: 99%

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confidence: 99%

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NGF administered by microdialysis into rabbit vitreous

Waga

Ehinger

2000

Acta Ophthalmologica Scandinavica

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“…Every other day, the condition of the implanted membrane was checked by a perfusion with [ 3 H]H 2 O, like we have done in our previous series (Waga et al 1991(Waga et al , 1995(Waga et al , 1997.…”

Section: Retrodialysis For Concentration Monitoring In the Vitreousmentioning

confidence: 99%

“…It has been adapted for ocular use in chronic experiments (Waga et al 1991). We have shown that it can be used for chronic administration of certain drugs into the rabbit vitreous (Waga & Ehinger 1995). This study aims to investigate the possibility of administrating ganciclovir into the rabbit vitreous by microdialysis.…”

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Ganciclovir delivery through an intravitreal microdialysis probe in rabbit

Waga

2000

Acta Ophthalmologica Scandinavica

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ABSTRACT.The treatment of cytomegalovirus retinitis has during the last years been done mainly with sustained release ganciclovir devices implanted in the vitreous. In the present study it is shown that ganciclovir can be administered into the rabbit vitreous by microdialysis. A concentration of about 10 ª6 M, which is considered within the therapeutic range, is achieved in the vitreous after a microdialysis perfusion. The method offers possibility of variation in the drug delivery that is not possible with the ganciclovir implants.

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Biodegradable scleral implant for controlled intraocular delivery of betamethasone phosphate

Kunou

Ogura

Honda

et al. 2000

J. Biomed. Mater. Res.

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We evaluated nail-like, biodegradable scleral implants as a controlled intraocular delivery system of betamethasone phosphate (BP) for the treatment of chronic uveitis using pigmented rabbits. The scleral implants, which contained 10% and 25% of BP (weight 8.5 mg; length 5 mm), were made of poly (D,L-lactide-co-glycolide) (PLGA). In vivo release and retinal toxicity after implantation were also studied in pigmented rabbits. The in vitro release studies demonstrated the 10% and 25% BP-loaded scleral implants released BP in a biphasic release pattern for at least 1 month. The BP concentrations in the vitreous and the retina/choroid after application of scleral implants in pigmented rabbit eyes stayed within the concentration range capable of suppressing inflammatory responses for over 1 month. The BP concentration was greater in the retina/choroid than in the vitreous throughout the study. No substantial toxic reactions in the retina were observed by electroretinography. Our findings suggest that the BP-loaded scleral implant may be a promising device for treatment of chronic uveitis.

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Passage of drugs through different intraocular microdialysis membranes

Abstract: We have shown that the above-mentioned substances penetrate into the vitreous body of rabbits through an implanted microdialysis membrane. This is of importance for the development of new means of intraocular drug administration.

Cited by 21 publications

References 18 publications

NGF administered by microdialysis into rabbit vitreous

NGF administered by microdialysis into rabbit vitreous

Ganciclovir delivery through an intravitreal microdialysis probe in rabbit

Biodegradable scleral implant for controlled intraocular delivery of betamethasone phosphate

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