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Biomedical subjects

A Kupferman

Publications and source records attributed to A Kupferman.

At least 37 records · Page 2Linked to original sources
PubMed1977

Periocular injection of corticosteroids: an experimental evaluation of its role in the treatment of corneal inflammation.

The present experiments demonstrate that subconjunctivally injected corticosteroids are less effective in suppressing corneal inflammation than are topically instilled corticosteroids. Topical administration of 6.5 mg of prednisolone acetate over a 30-hour period reduced corneal inflammatory activity by 52%. Subconjunctival injection of 50 mg of the same steroid, also given over a 30-hour period, yielded a 15% reduction in corneal inflammation. A fourfold increase (200 mg) in the quantity of prednisolone acetate injected subconjunctivally resulted in a nonsignificant (P less than .05) increment (24%) in anti-inflammatory effect. Dexamethasone sodium phosphate achieved a 30% reduction in corneal inflammation, the maximum effect observed after subconjunctival administration. The data suggest that different modes of corneal penetration are involved after drug delivery via the two routes. Concurrent administration of corticosteroids by the topical and subconjunctival routes seemingly produced an additive anti-inflammatory effect.

Administration, Topical↗
PubMed1977

Drug interaction in the eye. Concurrent corticosteroid-antibiotic therapy for inflammatory keratitis.

Concurrent instillation of individual preparations of a corticosteroid and an antibiotic resulted in significantly (P less than .05) lower peak corneal and aqueous humor steroid levels than those achieved by the steroid alone. Both the interval elapsing between instillation of the two drugs and the sequence in which they were administered influenced subsequent steroid bioavailability. Corticosteroid levels in the cornea after administration of a combination steroid-antibiotic preparation were not significantly different (P less than .05) from those detected after instillation of the same steroid alone, suggesting that, for the treatment of corneal disorders, use of a combination preparation may offer a method to circumvent certain drug interactions. The decrease in ocular steroid bioavailability could not be directly equated with differences in antinflammatory effectiveness, so that the therapeutic relevance of the demonstrated drug interaction is not known.

Adrenal Cortex Hormones↗
PubMed1977

Topical antibiotic therapy of staphylococcal keratitis.

The in vivo antibacterial effectiveness in the rabbit cornea of a number of commercially available ophthalmic antibiotic preparations was determined against a single strain of penicillinase-producing Staphylococcus aureus isolated from a human corneal ulcer. Each antibiotic was instilled topically at hourly intervals, and the number of residual viable organisms in the cornea subsequently was ascertained. In vivo measurements demonstrated that five antibiotics--neomycin sulfate, gentamicin sulfate, erythromycin, tetracycline hydrochloride, and chlortetracycline hydrochloride--were equally effective in suppressing growth of the strain of S aureus studied. Therapeutic results were the same whether the corneal epithelium was present of absent for each of the drugs studied. With one exception (chloramphenicol), there was excellent correlation between in vivo and in vitro findings.

Administration, Topical↗
PubMed1977

Penetration of topically administered prednisolone acetate into the human aqueous humor.

A single standardized drop of 1.0% prednisolone acetate labeled with tritiated thymidine was administered topically to one eye of 58 patients shortly before elective cataract extraction. An aqueous humor sample was aspirated at varying intervals and its corticosteroid content was determined. Peak drug concentration in aqueous humor was 1.13 mug/ml, which occurred 30 to 45 minutes after instillation of the medication. Substantial quantitites of corticosteroid were found in the aqueous humor five minutes after drug administration. The area under the drug concentration in aqueous humor-vs-time curve (a measure of the drug's bioavailability in aqueous humor) was 88 mug min/ml, and its half-life in human aqueous humor was 28 minutes. None of these values were significantly different from the comparable values in rabbit eyes.

Adult↗
PubMed1976

Kinetics of topically administered prednisolone acetate. Optimal concentration for treatment of inflammatory keratitis.

Two types of quantitative measurements were made in rabbit corneas. First, the level that varying concentrations of topically administered prednisolone acetate attained in the cornea and aqueous humor was determined. Then, the ability of varying concentrations of this corticosteroid to suppress corneal inflammation was ascertained. The maximum dose-response curve for anti-inflammatory effect in the cornea was achieved by the 1.0% concentration, the highest concentration commercially available. Higher concentrations permitted greater quantities of the drug to gain access to the cornea and aqueous humor but produced no measurable increment in anti-inflammatory effect. These experimental observations suggest that concentrations of prednisolone acetate higher than 1.0% have an increased potential for toxicity without offering additional therapeutic benefit.

Administration, Topical↗
PubMed1976

Quantitation of bacterial infection and antibiotic effect in the cornea.

We report an experimental model that allows objective quantitation of bacterial keratitis. The model permits direct measurement of the number of viable organisms in the cornea after varying periods of in vivo growth. The size of the inoculum used to produce the corneal infection is critical, and the experimental organism must be standardized for its growth characteristics in the cornea. The end point is an objective one, productive of numerical data that can be subjected to statistical analysis. The findings are highly reproducible and the system is sufficiently sensitive to indicate the ability of a topically administered antibiotic to reduce the number of viable organisms in the cornea of an outbred rabbit population.

Administration, Topical↗
PubMed1976

Biological equivalence of ophthalmic prednisolone acetate suspensions.

We compared both concentrations (0.125 and 1.0%) of two widely used commmerical brands of prednisolone acetate suspensions. We investigated the concentration that each product attained in the cornea and aqueous humor, and each product's anti-inflammatory effectiveness in the cornea. There was no statistically significant difference in the corticosteroid levels measured in cornea or aqueous humor after administration of the two suspensions. Similarly, there was no significant difference in the ability of the two commercial preparations to suppress corneal inflammation.

Acetates↗
PubMed1975

Penetration of fluorometholone into the cornea and aqueous humor.

In each of the experimental conditions studied, fluorometholone penetrated into the cornea and aqueous humor following topical administration of a standard drop. The amount of drug measured in each location was less than that previously documented for dexamethasone and prednisolone preparations. In contrast to these more conventional steroids, the ocular penetration of fluorometholone appeared to be unaffected by the presence or absence of the corneal epithelium or of intraocular inflammation.

Administration, Topical↗
PubMed1975

Therapeutic effectiveness of fluorometholone in inflammatory keratitis.

During an experimentally-induced inflammatory keratitis, we measured the ability of 0.1% fluorometholone ophthalmic suspension to reduce the numbers of polymorphonuclear leukocytes that invaded the cornea. The data demonstrate that topically administered fluorometholone is an effective therapeutic agent and that it compares favorably in anti-inflammatory activity with dexamethasone and prednisolone preparations. Comparison of our results with comparable studies of dexamethasone and prednisolone formulations indicates that 1.0% prednisolone acetate ophthalmic suspension is still the most effective corneal anti-inflammatory agent that we have investigated to date. However, the decreased potential of fluorometholone to produce secondary elevation of the intraocular pressure would appear to make it the drug of choice in situations in which maximum pharmacologic suppression of inflammation is not required and in chronic inflammatory conditions that require prolonged treatment.

Administration, Topical↗
PubMed1975

Anti-inflammatory effectiveness of topically administered corticosteroids in the cornea without epithelium.

The present studies demonstrate that modification of the derivative of a given steriod base alters its anti-inflammatory potential as measured by suppression of leukocyte invasion of the cornea. A comparison of each drug's corneal bioavailability with its anti-inflammatory effectiveness shows the acetate derivative of prednisolone to be a more potent anti-inflammatory agent than the phosphate derivative. Similarly, the free alcohol derivative of dexamethasone proved to be more potent than the phosphate derivative. Increasing the concentration of prednisolone acetate from 0.125 per cent to 1.0 per cent results in a significant increase in its anti-inflammatory effectiveness in the cornea following topical administration. The same increase in prednisolone phosphate concentration does not produce a significant increase in its ability to suppress polymorphonuclear leukocyte infiltration of the cornea. When the epithelium of the inflamed cornea is intact, prednisolone acetate, 1.0 per cent ophthalmic suspension, is the most effective of the corticosteroid preparations studied. In the absence of an intact epithelium, prednisolone acetate, 1.0 per cent ophthalmic suspension, again produces the greatest mean reduction in polymorphonuclear leukocytic infiltration of the cornea although here one cannot demonstrate a statistically significant difference from the anti-inflammatory effect produced by prednisolone phosphate, 1.0 per cent ophthalmic solution, or dexamethasone alcohol, 0.1 per cent ophthalmic suspension. Overall, therefore, prednisolone acetate 1.0 per cent is the most effective of the topical agents studied for suppression of corneal inflammation.

Administration, Topical↗