Effect of Paracentesis on Ocular Cloxacillin Concentration

Albrecht von Graefes Arch. Klin. Ophthalmol.

1977

Total antibiotic concentration of tetracycline hydrochloride was determined in the ocular structures of rabbits by radioactive tracer method. Concentration of tetracycline of 0.1 to 5 microgram/g, adequate to inhibit the growth of bacteria of high or medium susceptibility, was measured from all ocular structures with the exception of the lens. Tetracycline concentration in the aqueous humor was inferior to that in the vascularized ocular tissues and to that in the cornea. Vitreous body tetracycline level, about 0.3 microgram/g, was about half of the concentration in the aqueous humor. The disruption of the blood-aqueous barrier following paracentesis led to an immediate increase of tetracycline concentration in the anterior structures of the eye.

Penetration of ocular compartments by tetracyclines

Albrecht von Graefes Arch. Klin. Ophthalmol.

1977

Penetration of ocular compartments by tetracyclines

Albrecht von Graefes Arch. Klin. Ophthalmol.

1977

Using radioactive tracer method the distribution of intravenously injected doxycycline of 7 mg/kg was studied in the rabbit eye. Long-lasting antibiotic concentration of 1 microgram/g or more was measured from all vascularized ocular structures. Vitreous body doxycycline concentration, almost equal to that of aqueous humor, was 0.3 microgram/g. Doxycycline concentration in the cornea exceeded that in the aqueous humor. In all vascularized ocular structures plasma antibiotic concentration was at least once achieved, indicating good penetrability of doxycycline into the tissues. This good penetrability is obviously related to the high lipoidsolubility of doxycycline, whereas its high protein binding is reflected in low concentrations in the aqueous humor.

Cloxacillin Distribution in the Rabbit Eye After Intravenous Injection

1978

Acta Ophthalmologica

Self Cite

Distribution of isotopically labelled and intravenously injected cloxacillin was studied in rabbit eye. The antibiotic concentration determined by liquid scintillation counting proved to be a reliable measure of the total antibiotic concentration when controlled by microbiological assay. In the rabbit eye after an intravenous injection of 50 mg/kg of cloxacillin sodium, longlasting antibiotic concentration regarded as therapeutic against penicillinase producing staphylococci was obtained in all vascularized ocular structures and in the cornea. The antibiotic present in the iris and ciliary body, and in the retina and choroid preparations, proved to be partly intravascular, whereas it penetrated better into the extravascular tissue compartment of the sclera and limbal area. Cloxacillin failed to achieve a therapeutic antibiotic concentration in the vitreous body and in the lens. Administration of probenecid had an enhancing effect on ocular cloxacillin concentration allowing improved drug diffusion into the eye by means of an elevated plasma concentration. No specific ocular effect of probenecid was noticed. Therapeutic concentration of cloxacillin in the aqueous humour, otherwise barely achieved, was more satisfactorily obtained with a previous injection of probenecid.