Claims for Patent: 4,356,267

Summary for Patent: 4,356,267

Title:	Enzyme immobilization in cellulosic hollow fibres
Abstract:	Enzymes are immobilized in a bundle of cellulosic hollow fibres for use as a fibre-bundle dialyzer for purifying blood. Immobilization is carried out by circulating through the lumen of the fibres to activate the fibres an aqueous solution of sodium periodate at a concentration of 0.7-21 mg/ml, a circulation rate of 300-500 mm.sup.3 /minute/mm.sup.2, a temperature of 15.degree.-30.degree. C. and for a period not exceeding 70 minutes, removing excess sodium periodate by washing the fibres, and directly or indirectly anchoring an enzyme to the activated fibres. Washing is preferably carried out by circulating through the lumen of the fibres dionized water followed by a dilute aqueous solution of glycerol. The fibres containing an immobilized enzyme may be sterilized with a sterilizing agent.
Inventor(s):	Callegaro; Lanfranco (Padova, IT), Boniolo; Antonio (Saluggia, IT), Denti; Ennio (Pino Torinese, IT), Rosa; Umberto (Turin, IT), Rossi; Valdano (San Benedetto Po, IT)
Assignee:	Sorin Biomedica S.p.A. (Saluggia, IT)
Application Number:	06/233,702
Patent Claims:	1. A method for immobilizing an enzyme in a bundle of cellulosic hollow fibres for a fibre-bundle dialyzer for purifying blood, comprising the following sequential steps: (a) activating said cellulosic hollow fibres by circulating through the lumen of the fibres in the bundle an aqueous solution of sodium periodate at a concentration of 0.7-2.1 mg/ml, at a circulation rate of 300-500 mm.sup.3 /minute/mm.sup.2 at a temperature of 15.degree.-30.degree. C. for a period of time not exceeding 70 minutes. (b) removing excess sodium periodate by circulating through the lumens of the fibres in the bundle deionized water to a total volume amounting to at least 10 times the total volume of the lumens of the fibres, and subsequently circulating a dilute aqueous solution of glycerol to the lumens of the fibres in the bundle; and (c) directly or indirectly anchoring the enzyme to the activated cellulosic fibres through covalent linkages. 2. Method according to claim 1, wherein the periodate concentration does not exceed 5 mg/ml. 3. Method according to claim 1, wherein the periodate concentration is 1 mg/ml. 4. Method according to claim 1, wherein the circulation rate is 350-480 mm.sup.3 /min/mm.sup.2. 5. Method according to claim 4, wherein the circulation rate is 400 mm.sup.3 /min/mm.sup.2. 6. Method according to claim 1, wherein the temperature is from 18.degree. C. to 25.degree. C. and the time period is of 60 minutes. 7. Method according to claim 1, wherein the lumen diameter of the fibres is from 200 to 300 microns and the wall thickness of the fibres is 10-20 microns. 8. Method according to claim 1, wherein the enzyme is a glutathione transferase. 9. Method according to claim 1, wherein the enzyme is creatininase. 10. Method according to claim 1, wherein the enzyme is asparaginase. 11. Method according to claim 1, wherein the enzyme is beta-galactoxydase. 12. Method according to claim 1, wherein the enzyme is uricase. 13. Method according to claim 1, wherein the enzyme is arginase. 14. Method according to claim 1, wherein the glycerol concentration in the said solution is from 8 to 15 vol.%. 15. Method according to claim 1, wherein the glycerol concentration in said solution is 10 vol.%. 16. Method according to claim 1, wherein the fibre bundle containing the immobilized enzyme is sterilized by exposing the fibres to an external sterilizing agent while the fibres are filled with a buffer solution specific to the enzyme. 17. Method according to claim 16, wherein the sterilization is effected by exposing the fibres to a gamma-radiation at a dosage of 2.5 Mrad. 18. Method according to claim 16, wherein the sterilization is effected by exposing the fibres to a gaseous mixture of ethylene oxide and a "Freon". 19. Method according to claim 18, wherein the gaseous mixture consists of 12 vol.% of ethylene oxide and 88 vol.% of "Freon" 12. 20. Method according to claims 16 or 17, wherein the buffer solution additionally comprises glycerol as protective agent for the fibres.

Details for Patent 4,356,267

Applicant	Tradename	Biologic Ingredient	Dosage Form	BLA	Approval Date	Patent No.	Expiredate
Recordati Rare Diseases, Inc.	ELSPAR	asparaginase	For Injection	101063	01/10/1978		2000-02-13