Pilocarpine Therapy with Soft Contact Lenses

Podos, Steven M.; Becker, Bernard; Asseff, Carl F.; Hartstein, Jack

doi:10.1016/0002-9394(72)90062-1

Cited by 83 publications

(27 citation statements)

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“…Most of the studies of soaking time have' been confined to pilocarpine solution only. Podos et al 12 observed that with a 0-5% solution of pilocarpine the drug uptake appears to increase with the time of immersion, approaching a maximum after soaking the lens for 30 to 60 minutes.' Preliminary biochemical studies conducted by Hillman"' showed that approximately 24 hours' soaking is necessary to saturate a Sauflon lens, which then holds 400 to 500 ltg of pilocarpine.…”

Section: Discussionmentioning

confidence: 99%

Drug delivery through soft contact lenses.

Jain¹

1988

British Journal of Ophthalmology

105

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SUMMARY Clinical studies were conducted on 466 patients waiting for senile cataract surgery and receiving chloromycetin, gentamicin, or carbenicillin subconjunctivally and through New Sauflon 70 and New Sauflon 85 lenses. The aqueous drug levels were biologically estimated at various time intervals. Soft contact lenses provided significantly higher drug penetration than subconjunctival therapy. Both modes of treatment provided therapeutically effective levels against most of the common ocular pathogens for varying intervals of 2 to 12 hours.Soft contact lenses were initially used for drug delivery by Sedlavek in Czechoslovakia in 1965,' and since then many workers have advocated their use with various drugs. The hydrogel lenses, by virtue of their high water content and large intermolecular pore size, absorb water soluble drugs with some correlation with molecular weight, releasing them initially in a high pulse and then gradually, thereby complying with first order kinetics. However, the first order kinetics can be advantageously turned into practically zero order kinetics where sustained high concentration of the drug is obtained by superinstillation of drops at two-to four-hour intervals or reapplication of a soaked lens, depending on the need and severity of the condition.2Anterior segment inflammations, whether infective or allergic, and angle closure glaucoma are a few of the important clinical conditions requiring a high intraocular concentration of drugs. The drugs which can be conveniently delivered are the water soluble antibiotics, steroids (betamethasone, dexamethasone, and prednisolone), pilocarpine, atropine, and homatropine.The author has conducted various sets of clinical studies with the following aims: (1) to estimate and compare the penetration of various antibiotics into the aqueous after subconjunctival injection and soft contact lens delivery in relation to dosage and time;(2) to compare the drug penetration with hydrogel lenses of different water content. Material and methodsThe studies were conducted on 466 patients awaiting surgery for senile cataract. Eyes suffering from any kind of disease were not included in this study. The time of cataract incision was so planned as to provide a predetermined dose-to-sample time interval.In the subconjunctival group of cases the specified dose of antibiotic dissolved in 0-5 ml of distilled water was injected subconjunctivally, and the cases were divided into various subgroups depending on the dose-to-sample interval which varied over ¼/4, 1/2, 1, 2, 4, 8, and 12 hours.In the other group of cases soft contact lenses were used to deliver the drugs. The lenses employed were of two different water contents, namely, New Sauflon 70 and New Sauflon 85 (supplied by CLM, London). These lenses were afocal, of uniform thickness (0.2 mm), and of uniform diameter (14.0 mm); they had varying base curves of 8-0 to 9X0 mm. Each lens was soaked for half an hour in freshly prepared 0 5 ml solution containing the specified dose of antibiotic. Thereafter the lens was t...

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Section: Discussionmentioning

confidence: 99%

Drug delivery through soft contact lenses.

Jain¹

1988

British Journal of Ophthalmology

105

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“…Clinical dose-response patterns have been obtained for cchothiophate iodide, 1-epinephrine and pilocarpine under circumstances of routine clinical usage [5,7 ]. The mean maximal ocular hypotensive response for each of these drugs is in the range of 25-30%.…”

Section: Discussionmentioning

confidence: 99%

“…The mean maximal ocular hypotensive response for each of these drugs is in the range of 25-30%. With each drug a dose exists beyond which no further therapeutic response is achieved [5,7]. Increasing the drug beyond these ceiling levels, in at least one instance, produced side-effects at a much greater rate than therapeutic efficacy [5].…”

Section: Discussionmentioning

confidence: 99%

“…During the ensuing interval, attempts albeit largely unsuccessful, have been made to improve the efficacy and/or duration of action of commonly used anti-glaucomatous medications [8], It would now seem that it is feasible to achieve both of these goals through the usage of newer drug delivery systems [1,7].…”

Section: Discussionmentioning

confidence: 99%

“…An alter native approach to enhancing therapeutic efficacy and duration of action is by the use of drug delivery systems [1,7].…”

Section: Introductionmentioning

confidence: 99%

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