Posterior juxtascleral injection of anecortave acetate: magnetic resonance and echographic imaging and localization in rabbit eyes.
OBJECTIVE
To confirm juxtascleral delivery of anecortave acetate in rabbit eyes by ocular imaging techniques and to determine drug localization and distribution as a function of time after injection.


METHODS
Four female New Zealand white rabbits (weight, 2.5-3.0 kg) received a single juxtascleral posterior sub-Tenon capsule injection of 0.5 mL or 1 mL of 30 mg/mL anecortave acetate. Rabbit eyes were imaged with ultrasonography and magnetic resonance imaging (MRI) before injection, immediately after injection, and at 2 hours, 1 week, and 4 weeks after injection. Rabbit eyes were also imaged with b-mode ultrasonography during the juxtascleral injections.


RESULTS
Ultrasonography and MRI demonstrated that juxtascleral posterior sub-Tenon capsule injection of anecortave acetate effectively delivered the drug in direct apposition to the posterior pole of the rabbit eye. The drug remained in the juxtascleral site for at least 5 weeks. The drug was visualized clearly by MRI immediately after injection, decreasing in intensity thereafter. Cannula insertion and the drug delivery process were clearly visualized by real-time ultrasound analysis. Immediately after drug injection, ultrasonography indirectly localized anecortave acetate localization as an echolucent zone posterior to the scleral surface. At the later time points, however, the juxtascleral location of the drug was verified with ultrasonography as a relatively echogenic focus in the same location.


CONCLUSIONS
Juxtascleral administration of anecortave acetate via a posterior sub-Tenon capsule approach effectively delivered the drug to the desired position in direct apposition to the globe posteriorly. MRI and ultrasonography both demonstrated that anecortave acetate remained localized to this location for at least 5 weeks after initial injection.
Jockovich
Maria-Elena
ME
Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida 33101, USA.
Murray
Timothy G
TG
Clifford
Paul D
PD
Moshfeghi
Andrew A
AA
D020533:Angiogenesis Inhibitors / Q000008:administration & dosage* / Q000493:pharmacokinetics; D000818:Animals; D003238:Connective Tissue / Q000000981:diagnostic imaging* / Q000187:drug effects; D016503:Drug Delivery Systems; D005260:Female; D007267:Injections; D008279:Magnetic Resonance Imaging; D009915:Orbit / Q000000981:diagnostic imaging; D011244:Pregnadienediols / Q000008:administration & dosage* / Q000493:pharmacokinetics; D011817:Rabbits; D012160:Retina / Q000000981:diagnostic imaging; D012590:Sclera / Q000000981:diagnostic imaging* / Q000187:drug effects*; D014018:Tissue Distribution; D014463:Ultrasonography
D020533:Angiogenesis Inhibitors; D011244:Pregnadienediols; C418047:anecortave acetate