Method of removing endotoxin

Claim 1

A method of removing endotoxin from a solution containing endotoxin and other materials, endotoxin being the only material int he solution absorbable onto a crosslinked granular chitosan, comprising, adjusting the pH value of the solution to pH 9 or lower, and passing the solution containing endotoxin through a column packed with the crosslinked granular chitosan, said crosslinked granular chitosan being prepared by crosslinking chitosan by a crosslinking reagent of 0.2-0.8 equivalent amount based on one equivalent amount of amino groups in chitosan.

Claim 2

A method of removing endotoxin from a solution containing endotoxin and other materials, endotoxin being the only material int he solution absorbable onto a crosslinked granular chitosan, comprising, adjusting the pH value of the solution to pH 9 or lower, and passing the solution containing endotoxin through a column packed with the crosslinked granular chitosan, said crosslinked granular chitosan being prepared by crosslinking chitosan by a crosslinking reagent of 0.2-0.8 equivalent amount based on one equivalent amount of amino groups in chitosan.

Claim 6

A method of removing endotoxin from a solution containing protein and endotoxin, comprising, adjusting the pH value of the solution equal to or lower than the isoelectric point of said protein, and passing the solution containing protein and endotoxin through a column packed with a crosslinked granular chitosan, said crosslinked granular chitosan being prepared by crosslinking chitosan by a crosslinking reagent of 0.2-0.8 equivalent amount based on one equivalent amount of amino groups in chitosan.

Claim 7

A method of removing endotoxin from a solution containing protein and endotoxin, comprising, adjusting the pH value of the solution equal to or lower than the isoelectric point of said protein, and passing the solution containing protein and endotoxin through a column packed with a crosslinked granular chitosan, said crosslinked granular chitosan being prepared by crosslinking chitosan by a crosslinking reagent of 0.2-0.8 equivalent amount based on one equivalent amount of amino groups in chitosan.

Claim 11

A method of removing endotoxin from a solution containing endotoxin and other materials, endotoxin being the only material in the solution absorbable onto a crosslinked granular chitosan, comprising, dispersing an aqueous acidic solution of chitosan into a hydrophobic dispersant, said solution including water, evaporating water while stirring with a stirring blade under a condition of rotation of 300-5,000 r.p.m. and a peripheral velocity of 1-20 m/sec to form a porous granular chitosan, crosslinking the porous granular chitosan by a crosslinking reagent of 0.2-0.8 equivalent amount based on one equivalent amount of amino groups in the porous granular chitosan to thereby form the crosslinked granular chitosan, adjusting the pH value of the solution to pH 9 or lower, and passing the solution containing endotoxin through a column packed with the crosslinked granular chitosan so that endotoxin contained in the solution is removed from the solution at a level of pg/ml.

Claim 12

A method of removing endotoxin from a solution containing endotoxin and other materials, endotoxin being the only material in the solution absorbable onto a crosslinked granular chitosan, comprising, dispersing an aqueous acidic solution of chitosan into a hydrophobic dispersant, said solution including water, evaporating water while stirring with a stirring blade under a condition of rotation of 300-5,000 r.p.m. and a peripheral velocity of 1-20 m/sec to form a porous granular chitosan, crosslinking the porous granular chitosan by a crosslinking reagent of 0.2-0.8 equivalent amount based on one equivalent amount of amino groups in the porous granular chitosan to thereby form the crosslinked granular chitosan, adjusting the pH value of the solution to pH 9 or lower, and passing the solution containing endotoxin through a column packed with the crosslinked granular chitosan so that endotoxin contained in the solution is removed from the solution at a level of pg/ml.

Claim 13

A method of removing endotoxin from a solution containing protein and endotoxin, comprising, dispersing an aqueous acidic solution of chitosan into a hydrophobic dispersant, said solution including water, evaporating water while stirring with a stirring blade under a condition of rotation of 300-5,000 r.p.m. and a peripheral velocity of 1-20 m/sec to form a porous granular chitosan, crosslinking the porous granular chitosan by a crosslinking reagent of 0.2-0.8 equivalent amount based on one equivalent amount of amino groups in the porous granular chitosan to thereby form the crosslinked granular chitosan, adjusting the pH value of the solution equal to or lower than the isoelectric point of said protein, and passing the solution containing protein and endotoxin through a column packed with the crosslinked granular chitosan so that endotoxin contained in the solution is removed from the solution at a level of pg/ml.

Claim 14

A method of removing endotoxin from a solution containing protein and endotoxin, comprising, dispersing an aqueous acidic solution of chitosan into a hydrophobic dispersant, said solution including water, evaporating water while stirring with a stirring blade under a condition of rotation of 300-5,000 r.p.m. and a peripheral velocity of 1-20 m/sec to form a porous granular chitosan, crosslinking the porous granular chitosan by a crosslinking reagent of 0.2-0.8 equivalent amount based on one equivalent amount of amino groups in the porous granular chitosan to thereby form the crosslinked granular chitosan, adjusting the pH value of the solution equal to or lower than the isoelectric point of said protein, and passing the solution containing protein and endotoxin through a column packed with the crosslinked granular chitosan so that endotoxin contained in the solution is removed from the solution at a level of pg/ml.