Use of Photoactivated Crosslinking Agents for Vascular Repair and Local Drug Delivery Kaia L. Kloster, Ph.D. Avera Research Institute PhotoBioMed Corporation University of South Dakota School of Medicine

4-amino-1,8-naphthalimides

Photochemistry

Light Activation Protocol Blue light Argon laser – 457 nm High pressure mercury arc lamp with filters producing nm range (predominantly 450 nm) ~240 J/cm 2 Not associated with excessive heat or protein denaturation

Naphthalimide Embodiments Tethers  Extenders  Crosslinkers

Crosslinkers Tissue Substrate #1Tissue Substrate #2 **** **** Photoactivation results in reactive sites (*) that form covalent bonds between tissue substrates. Requires blue light and compression.

Extenders Tissue Substrate #1 Tissue Substrate #2 Less dependent on light and compression

Tethers Tissue Substrate **** Photoactivation results in a reactive site (*) that forms a covalent bond with a tissue substrate. Requires blue light D D D D D D D D D D D D D

Naphthalimide Technology PBM parent technology

Coronary Artery Disease Leading cause of morbidity and mortality in the industrialized world Balloon Angioplasty Restenosis occurs in 30-50% of cases Coronary Stents Restenosis reduced to 10-30% Drug-Eluting Stents Promise of eliminating restenosis Concerns regarding late adverse effects

Concept of the Endogenous Stent Crosslink arterial proteins in the dilated state Repair intimal or medial dissections Tether anti-restenotic agents

Assumptions Ability to penetrate the arterial wall Ability to deliver the compounds intraluminally Ability to bond atheromatous arterial tissue Ability to locally delivery and tether anti- restenotic agents

Penetration of the Arterial Wall Hydrophilic Combined Lipophilic Immersion of Arterial Segments

Penetration of the Arterial Wall Intraluminal Delivery DISPATCH™ Coronary Infusion Catheter SciMed®

Penetration of the Arterial Wall Homogenization of control and experimental tissue Preparation of a standard curve and unknowns Fluorescent plate reader to assess relative fluorescence Extrapolation of the naphthalimide content present in experimental specimens Flurometric Assay Protocol

Intraluminal Delivery Immersion

Intraluminal Delivery Immersion

Penetration of the Arterial Wall Dispatch delivery Control 10-min washout Intraluminal Delivery Hydrophilic Film Exposure 2 sec 2 sec 20 sec

Tissue Bonding Protocol

Arterial Tissue Bonding *

In Vitro Simulation Air desiccation model to create atherosclerotic lesions in rabbit carotid arteries Atherosclerotic arteries dissected and mounted in an isolated arterial perfusion apparatus In vitro simulation of balloon angioplasty followed by napthalimide treatment or various controls NAP/LT*; PBS/DK; PBS/LT; NAP/DK Perfusion fixation of isolated arteries Histological examination and image analyses

Retention of Dilated State

Repair of Intimal Dissections

Local Drug Delivery Target Tissue drug reactive tether

Local Drug Delivery Target Tissue

Local Drug Delivery Target Tissue Restored blood flow will wash out any untethered drug molecules

Tethering of Anti-Restenotic Agents

Intraluminal Delivery of Heparin Drug delivery to the injured arterial wall post-angioplasty (arrows indicate heavy heparin loading on the blood surface of the artery)

Summary Delivery to the arterial wall Tissue bonding Retention of luminal gains Potential repair of intimal and medial dissections Tethering of anti-restenotic agents Potential for improved long-term outcomes for coronary revascularization procedures

Future Directions Determine if photoactivation of the naphthalimides improves retention rates upon reperfusion Develop a multifunctional catheter, ideally capable of: Balloon angioplasty Local delivery Perfusion Light activation Initiate chronic animal experimentation

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Additional Applications Ophthalmology Dermatology Vascular Repair Vascular Grafting Urology Dental Veterinary