Ocular Tissue Absorption of Gentamicin

Golden, Bruce; Coppel, Suzanne

doi:10.1001/archopht.1970.00990040794020

Cited by 55 publications

(4 citation statements)

References 9 publications

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“…Gentamicin has been the object of several studies, and there are adequate data bases for tobramycin, car- HILLMAN et al 1979;d MATHALONE and HARDING 1972;• FURGIUELE 1970;f PETOUNIS et al 1978;g BOYLE et al 1971;h BOYLE et al 1972a;i UWAYDAH et al 1976;i BOYLE et al 1972b;k JAIN and SRIVASTAVA 1978;1 MAURICE and OTA 1978;m FURGIUELE 1967;n LITWACK et al 1969;° GoLDEN and COPPEL 1970;P KUMING and TOMKIN 1974;q OAKLEY et al 1976;r BARZA et al 1977;' OISHI et al 1975;1 MELIKIAN et al 1971;U BLOOME et al 1970;• OISHI et al 1977;W FARIS et al 1980;Y P APAPANOS et al 1961 a;Z REcORDS 1967;aa SORSBY and UNGAR 1947;bb ANDREWS 1947;cc LEPRI 1950;dd OAKLEY et al 1976;·· HAMARD etal. 1975/ f AZUMAetal.…”

Section: Aqueous Humor Concentrationmentioning

confidence: 99%

Ocular Pharmacokinetics

Maurice¹,

Mishima²

1984

Handbook of Experimental Pharmacology

224

169

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Section: Aqueous Humor Concentrationmentioning

confidence: 99%

Ocular Pharmacokinetics

Maurice¹,

Mishima²

1984

Handbook of Experimental Pharmacology

224

169

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“…Excluding those sera with no detectable activity by either method, we found that in 23 instances (72%) the results of the two procedures agreed within 0.5 ,g/ml and in all instances the results agreed within 1.0 ,ug/ml. DISCUSSION ctf the volume of seeded agar to 5 ml Oden and co-workers (8) described two metheased the zone diameter of the cor-ods for microbiological assay of gentamicin, of 2.0,g/ml to 22.5 mm; however, based on those described by Grove and Randall )inion that a uniformly distributed (5) 23 25 microbiological assay procedures (1,4,7,12). In addition, the use of larger inocula in agar-difSIze of zone, mm fusion or disc-plate assay procedures has dedard dose-response curve of gentamicin creased the incubation time of assays to 3 to 6 hr S. aureus ATCC 6538P.…”

Section: Resultsmentioning

confidence: 99%

Four-Hour Microbiological Assay of Gentamicin in Serum

Warren

Snyder

Washington

1972

Antimicrob Agents Chemother

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(Difco control no. 544244) was autoclaved and adjusted to pH 7.9. To bottles containing 98 ml of the melted agar cooled to 50 C was added 2.0 ml of a well-mixed 18-hr Trypticase Soy Broth (BBL) culture of S. aureus ATCC 6538P. Viable-colony counts of this inoculum, determined on 10 separate occasions, ranged from 2.4 X 10U to 1.8 X 109 colony-forming units (CFU)/ml (mean, 6.6 X 108 CFU/ml). Portions of 9 ml of the seeded agar, containing an average of 1.2 X 107 CFU/ml, were pipetted into plastic petri dishes (100 by 15 mm) and allowed to harden; the plates then were stored at 5 C for a maximum of 5 days.Preparation (no. 740E, Schleicher & Schuell Co.), were saturated with each of the dilutions of gentamicin and placed on the surface of the seeded agar (each disc absorbs approximately 0.08 ml of solution). The solution containing 2.0 ,4g/ml was selected as the reference standard. Two discs saturated with the reference standard were placed on each assay plate opposite each other, and two other discs saturated with 1, 4, or 5 ,g/ml were placed in the other two quadrants.These concentrations were replicated 20 times. All plates were incubated for 4 hr at 37 C. The diameters of the zones of inhibition of the reference standard discs were measured by use of a dark-field Quebec bacterial colony counter with a millimeter scale on the glass; the mean of these values was taken as the correction point. Mean diameters of inhibition zones at 1, 4, and 5 jAg/ml were corrected according to the deviation from the correction point of the reference standard tested on the same plate. The corrected zone diameters of 5.0, 4.0, and 1.0 ,ug/ml with the correction point of 2.0 jug/ml were plotted against concentration on semilogarithmic paper.Assay procedure. Serum samples containing unknown concentrations of antibiotic were diluted 1:2, 1:4, and 1:5 in sterile pooled human serum (previously tested for antibacterial activity against S. aureus ATCC 6538P). Four seeded agar plates were used, each with two discs saturated with the reference standard and two discs saturated with the patient's undiluted or diluted serum. For maximal accuracy, duplicate plates were set up with discs saturated with diluted serum. The plates were incubated for 4 hr at 37 C. Zone diameters of the reference standards and of the patient's serum were measured and averaged. Correction of the zone diameter was accomplished by adding or subtracting the difference between the mean zone diameter of the reference standard obtained in the assay plate and the zone diameter of the correction point of 2.0 ,ug/ml in the standard

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“…Various investigators studied the bioavailability of aminoglycosides after topical application of drops [17,62,63], as summarized in table 1, and after subconjunctival delivery [57,[64][65][66][67]. The comparative data shown in table 1 indicate that aminoglycosides, mainly gentamicin and tobramycin but not netilmicin, have a relatively long bioavailability varying from 18 to 24 h as compared with other antibiotics as cephaloridine [68].…”

Section: Aminoglycosidesmentioning

confidence: 99%

Chapter 4: Requirements Concerning Antiseptics for Periorbital, Orbital and Intraorbital Application. 4.4.: Pharmacokinetics of Ophthalmic Drugs

Tawfik-Schlieper¹

2002

Developments in Ophthalmology

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The eye is a specialized sensory organ that is relatively secluded from systemic access by the blood-retinal, blood-aqueous and blood-vitreous barriers [1].Most of the ocular diseases are treated with topical application of eyedrops.Topical delivery in the lower cul-de-sac is the most common method for application. The site of action for most ophthalmic drugs is located in the inner eye. 2.1. Limiting Factors for the Resorption to the EyeExternal eye structures are readily accessible for topical application, but several factors limit the entry of drugs to the eye structure from the tear film. The following main factors may be responsible for this limitation: (a) the corneal barrier; (b) drug binding to proteins in the tear fluid; (c) nonproductive absorption to the conjunctiva of the eye, or (d) rapid loss of the instilled solution from the precorneal area, also by nasolacrimal drainage. 2.2.Absorption takes place through the cornea, the conjunctival tissue and the nasal mucosa.The main factors influencing drug distribution and absorption are summarized in figure 1.The diffusion of an antimicrobial agent across the corneal barrier is influenced by the concentration of the drug at the epithelial surface (diffusion along the concentration gradient), the degree to which the drug is soluble in both aqueous and lipid phases, and the amount of nonionized drug (more diffusible) compared to the ionized drug (less diffusible) at a physiological pH of 7.4. The epithelium, which is lipoidal in nature and has tight junctions, serves as a barrier to diffusion of drugs from the tears into the eye, and diffusion of drugs being amphoteric in nature is facilitated [3,4].

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Ocular Tissue Absorption of Gentamicin

Cited by 55 publications

References 9 publications

Ocular Pharmacokinetics

Ocular Pharmacokinetics

Four-Hour Microbiological Assay of Gentamicin in Serum

Chapter 4: Requirements Concerning Antiseptics for Periorbital, Orbital and Intraorbital Application. 4.4.: Pharmacokinetics of Ophthalmic Drugs

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