The United States of America as Represented by the Secretary of

The United States of America as Represented by the Department of Health

Robert L Dedrick

Edward H Oldfield

Paul F Morrison

Douglas W Laske

Robert J Lutz

Richard Hunt Bobo

Daniel S Zaharko

A method of high-flow microinfusion which provides convection-enhanced delivery of agents into the brain and other solid tissue structures. The method involves positioning the tip of an infusion catheter within a tissue structure and supplying an agent through the catheter while maintaining a pressure gradient from the tip of the catheter during infusion. Agent delivery rates of 0.5 to 15.0 .mu.l/min have been used experimentally with infusion distances greater than 1 cm from the delivery source. The method can be used to delivery various drugs, protein toxins, antibodies for treatment or imaging, proteins in enzyme replacement therapy, growth factors in the treatment of various neurodegenerative disorders and viruses and gene therapy. An infusion catheter developed for the high-flow microinfusion includes a plurality of elongated slits adjacent a tapered portion of the catheter which are parallel to the axis of the catheter and spaced symmetrically about the circumference thereof. The infusion catheter is used in a convention-enhanced delivery system in which, after the infusion catheter is positioned in a tissue situs, it is connected to a pump which delivers a desired agent and maintains a desired pressure gradient throughout delivery of the agent.

Convection-enhanced drug delivery

The subject invention is directed to an apparatus which selectively contr the rate with which a drug contained therein is released to surrounding tissue. Moreover, the subject invention is directed to process for controlling said release which comprises sealing the end of a suitable vessel with a non-porous material, inserting into said vessel a suitable medicament, and sealing the opposite end thereof with a porous neutral hydrogel through which naturally occuring materials can diffuse and further through which said medicament may diffuse.

Apparatus for controlling the release of a drug

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McLean, VA, United States of America

Robert L Dedrick