Movement of Albumin and Dextran Through the Sclera

Modeling of Corneal and Retinal Pharmacokinetics after Periocular Drug Administration

“…Using animal models, Robinson et al 14 showed that the conjunctival circulation and lymphatics play a much greater role in the elimination of drugs after periocular administration compared with the clearance by the choroidal circulation. This route is even believed to be responsible for the clearance of macromolecules from the periocular site, as was shown in the case of albumin by Bill,54,55 who demonstrated that the albumin is eliminated partly by the conjunctival circulation and lymphatics. We also found that the conjunctival circulation and lymphatics could be playing a role in the clearance of small (20 nm) nanoparticles.…”

Modeling of Corneal and Retinal Pharmacokinetics after Periocular Drug Administration

“…Using animal models, Robinson et al 14 showed that the conjunctival circulation and lymphatics play a much greater role in the elimination of drugs after periocular administration compared with the clearance by the choroidal circulation. This route is even believed to be responsible for the clearance of macromolecules from the periocular site, as was shown in the case of albumin by Bill,54,55 who demonstrated that the albumin is eliminated partly by the conjunctival circulation and lymphatics. We also found that the conjunctival circulation and lymphatics could be playing a role in the clearance of small (20 nm) nanoparticles.…”

Controlled Drug Release from an Ocular Implant: An Evaluation Using Dynamic Three-Dimensional Magnetic Resonance Imaging

“…In our study, the presence of a high concentration of Gd-DTPA in the buccal lymph node, the proximal portion of the cervical lymph drainage system, 20 was consistent with previous work showing radiolabeled compounds being eliminated from the subconjunctival space. 21 The relatively low flow rates of the lymph fluid in this region enables imaging of pooled Gd-DTPA in the lymph node. 16 Entry and elimination of Gd-DTPA from the episcleral veins is difficult to image because of the rapid dilution of Gd-DTPA as it enters the blood stream.…”

“…31 The movement of Gd-DTPA released from an intravitreal implant through the neurosensory retina was observed in both in vivo and ex vivo eyes, consistent with the lack of tight junctional barriers in the neurosensory retina. 32 Although choroidal tissue fluid can leave the eye through the sclera, either in or around perivascular spaces, 21,24,33 in the in vivo intravitreal implant eyes, no Gd-DTPA was detected in the posterior sclera, suggesting that the elimination of Gd-DTPA was predominantly through the choroidal circulation. The minimal Gd-DTPA movement beyond the posterior retina in the ex vivo eyes suggested that the tight junctions between the RPE cells were intact and that the clearance mechanisms, such as choroidal blood flow, were inactivated.…”

Elevated concentration of intraocular cortisol obtained by sequential parabulbar injection in rabbit model12

“…Hydrocortisone probably penetrates the eye directly through the adjacent sclera [2]. An echographic study of parabulbar corticosteroids indicated that the closer the deposit is to the chorioretinal lesion, the greater the response [3].…”

Modeling of Corneal and Retinal Pharmacokinetics after Periocular Drug Administration

“…Using animal models, Robinson et al 14 showed that the conjunctival circulation and lymphatics play a much greater role in the elimination of drugs after periocular administration compared with the clearance by the choroidal circulation. This route is even believed to be responsible for the clearance of macromolecules from the periocular site, as was shown in the case of albumin by Bill,54,55 who demonstrated that the albumin is eliminated partly by the conjunctival circulation and lymphatics. We also found that the conjunctival circulation and lymphatics could be playing a role in the clearance of small (20 nm) nanoparticles.…”

Controlled Drug Release from an Ocular Implant: An Evaluation Using Dynamic Three-Dimensional Magnetic Resonance Imaging

“…In our study, the presence of a high concentration of Gd-DTPA in the buccal lymph node, the proximal portion of the cervical lymph drainage system, 20 was consistent with previous work showing radiolabeled compounds being eliminated from the subconjunctival space. 21 The relatively low flow rates of the lymph fluid in this region enables imaging of pooled Gd-DTPA in the lymph node. 16 Entry and elimination of Gd-DTPA from the episcleral veins is difficult to image because of the rapid dilution of Gd-DTPA as it enters the blood stream.…”

“…31 The movement of Gd-DTPA released from an intravitreal implant through the neurosensory retina was observed in both in vivo and ex vivo eyes, consistent with the lack of tight junctional barriers in the neurosensory retina. 32 Although choroidal tissue fluid can leave the eye through the sclera, either in or around perivascular spaces, 21,24,33 in the in vivo intravitreal implant eyes, no Gd-DTPA was detected in the posterior sclera, suggesting that the elimination of Gd-DTPA was predominantly through the choroidal circulation. The minimal Gd-DTPA movement beyond the posterior retina in the ex vivo eyes suggested that the tight junctions between the RPE cells were intact and that the clearance mechanisms, such as choroidal blood flow, were inactivated.…”

Elevated concentration of intraocular cortisol obtained by sequential parabulbar injection in rabbit model12

“…Hydrocortisone probably penetrates the eye directly through the adjacent sclera [2]. An echographic study of parabulbar corticosteroids indicated that the closer the deposit is to the chorioretinal lesion, the greater the response [3].…”

Modeling of Corneal and Retinal Pharmacokinetics after Periocular Drug Administration

“…Using animal models, Robinson et al 14 showed that the conjunctival circulation and lymphatics play a much greater role in the elimination of drugs after periocular administration compared with the clearance by the choroidal circulation. This route is even believed to be responsible for the clearance of macromolecules from the periocular site, as was shown in the case of albumin by Bill,54,55 who demonstrated that the albumin is eliminated partly by the conjunctival circulation and lymphatics. We also found that the conjunctival circulation and lymphatics could be playing a role in the clearance of small (20 nm) nanoparticles.…”

Controlled Drug Release from an Ocular Implant: An Evaluation Using Dynamic Three-Dimensional Magnetic Resonance Imaging

“…In our study, the presence of a high concentration of Gd-DTPA in the buccal lymph node, the proximal portion of the cervical lymph drainage system, 20 was consistent with previous work showing radiolabeled compounds being eliminated from the subconjunctival space. 21 The relatively low flow rates of the lymph fluid in this region enables imaging of pooled Gd-DTPA in the lymph node. 16 Entry and elimination of Gd-DTPA from the episcleral veins is difficult to image because of the rapid dilution of Gd-DTPA as it enters the blood stream.…”

“…31 The movement of Gd-DTPA released from an intravitreal implant through the neurosensory retina was observed in both in vivo and ex vivo eyes, consistent with the lack of tight junctional barriers in the neurosensory retina. 32 Although choroidal tissue fluid can leave the eye through the sclera, either in or around perivascular spaces, 21,24,33 in the in vivo intravitreal implant eyes, no Gd-DTPA was detected in the posterior sclera, suggesting that the elimination of Gd-DTPA was predominantly through the choroidal circulation. The minimal Gd-DTPA movement beyond the posterior retina in the ex vivo eyes suggested that the tight junctions between the RPE cells were intact and that the clearance mechanisms, such as choroidal blood flow, were inactivated.…”

Elevated concentration of intraocular cortisol obtained by sequential parabulbar injection in rabbit model12

“…Hydrocortisone probably penetrates the eye directly through the adjacent sclera [2]. An echographic study of parabulbar corticosteroids indicated that the closer the deposit is to the chorioretinal lesion, the greater the response [3].…”