Dialysate filter including an asymmetric microporous, hollow fiber membrane incorporating a polyimide

Abstract

A dialysate filter including asymmetric, microporous, hollow fiber membranes incorporating a polyimide. The dialysate filter connects to the dialysis machine immediately before the dialyzer ensuring complete filtration of the dialysate, easy visual inspection, quick installation and removal, and easy disinfection of the filter.

We claim: 
     
       1. A filter comprising; a housing defining an interior chamber;   an inlet port connected to said housing;   an outlet port connected to said housing;   an access port connected to said housing; and   a bundle of asymmetric, microporous, hollow fiber membranes disposed within said interior chamber, said asymmetric, microporous, hollow fiber membranes comprising a polyimide polymer, said asymmetric, microporous, hollow fiber membranes including pores having a pore size range from about 0.005 μm to about 0.2 μm, wherein said asymmetric, microporous, hollow fiber membranes have a flux in excess of about 75×10 -5  ml/(min×cm 2  ×mmHg); and wherein said inlet port, said outlet port and said access port are in fluid communication with said bundle of hollow fiber membranes.     
     
     
       2. The filter of claim 1 wherein said fiber comprises 100 wt. % of said polyimide polymer. 
     
     
       3. The filter of claim .[.2.]. .Iadd.1 .Iaddend.wherein said polyimide polymer comprises a polymer having the structure: ##STR5## 10% to 90% of the R groups are ##STR6## and the remaining R groups are ##STR7## 
     
     
       4. The filter of claim 3 wherein said fiber comprises from about 100 wt. % of said polyimide polymer. 
     
     
       5. The filter of claim 1 wherein said polyimide polymer comprises a polymer having the structure: 
     
     
       6. The filter of claim 5 wherein said .[.fiber.]. .Iadd.polyimide polymer .Iaddend.comprises from about 100 wt. % of said polyimide polymer. 
     
     
       7. The filter of claim 2 wherein said polyimide polymer comprises a polymer having the structure: wherein 10% to 90% of the R groups are ##STR8## and the remaining R groups are ##STR9## 
     
     
       8. .[.The filter of claim 7 wherein said polyimide polymer comprises from about 100 wt. % of said polyimide polymer..]. .Iadd.The filter of claim 2 wherein said polyimide polymer comprises a polymer having the structure:.Iaddend. 
     
     
       9. The filter of claim 1 wherein said polyimide polymer has a molecular weight of about 40,000 daltons to about 105,000 daltons. 
     
     
       10. The filter of claim 1 wherein said membranes are uniformly porous throughout and wherein said membranes are characterized by the absence of voids. 
     
     
       11. The filter of claim 1 wherein said membranes are capable of being subjected to take-up rates in excess of 45 m/min during manufacturing. 
     
     
       12. The filter of claim 1 wherein said membranes rewet by maintaining a flux of at least 500 ml/(hr×m 2  ×mmHg) for six or more sterilizations and wherein said asymmetric, microporous, hollow fiber membranes are further characterized by having 0.0% wetting agent additives selected from the group of hydrophilic polymers, nonionic, anionic, or amphoteric surfactants. 
     
     
       13. The filter of claim 12 wherein said hydrophilic polymers comprise polyvinylpyrrolidone. 
     
     
       14. The filter of claim 1 wherein the housing is a material selected from polycarbonate, polyethylene or polypropylene. 
     
     
       15. The filter of claim 1 wherein the housing is polycarbonate. 
     
     
       16. A dialysis apparatus comprising: a dialysis system comprising an artificial kidney operatively connected to said dialysis system, said artificial kidney including a dialysate inlet port;   a female to female connector; and   a dialysate filter, said dialysate filter comprising: a bundle of asymmetric, microporous, hollow fiber membranes;   a filter housing defining an interior chamber;   a dialysate inlet port connected to said filter housing;   a dialysate outlet port connected to said filter housing;   a dialysate access port connected to said filter housing; and said bundle of asymmetric, microporous, hollow fiber membranes disposed within said interior chamber, said asymmetric microporous hollow fiber membranes comprising a polyimide polymer, said asymmetric, microporous, hollow fiber membranes including pores having a pore size range from about 0.005 μm to about 0.2 μm, and having a flux in excess of about 75×10 -5  ml/(min×cm 2  ×mmHg); said dialysate inlet port, said dialysate outlet port and said access port are in fluid communication with said bundle of hollow fiber membranes; and       wherein the dialysate filter is located upstream of the artificial kidney and is connected through the female to female connector to the inlet port of said artificial kidney.   
     
     
       17. The dialysis apparatus of claim 16 wherein said filter is connected directly to said female to female connector at the dialysate inlet port of said artificial kidney. 
     
     
       18. .[.A.]. .Iadd.The .Iaddend.dialysis apparatus .[.comprising.]. of claim 16 wherein said filter is connected to said female to female connector by a hose. 
     
     
       19. The dialysis apparatus of claim 16 wherein said fiber comprises 100 wt. % of said polyimide polymer. 
     
     
       20. The filter of claim 16 wherein said polyimide polymer comprises a polymer having the structure: ##STR10## wherein 10% to 90% of the R groups are ##STR11## and the remaining R groups are ##STR12## 
     
     
       21. The dialysis apparatus of claim 20 wherein said fiber comprises from about 100 wt. % of said polyimide polymer. 
     
     
       22. The dialysis apparatus of claim 16 wherein said polyimide polymer comprises a polymer having the structure: 
     
     
       23. The dialysis apparatus of claim 22 wherein said polyimide polymer comprises from about 100 wt. % of said polyimide polymer. 
     
     
       24. The dialysis apparatus of claim 16 wherein said polyimide polymer has a molecular weight of about 40,000 daltons to about 105,000 daltons. 
     
     
       25. The dialysis apparatus of claim 16 wherein said membranes are uniformly porous throughout and wherein said membranes are characterized by the absence of voids. 
     
     
       26. The dialysis apparatus of claim 16 wherein said membranes are capable of being subjected to take-up rates in excess of 45 m/min during manufacturing. 
     
     
       27. The filter of claim 16 wherein said membranes rewet by maintaining a flux of at least 500 ml/(hr×m 2  ×mmHg) for six or more sterilizations and wherein said asymmetric, microporous, hollow fiber membranes are further characterized by having 0.0% wetting agent additives selected from the group of hydrophilic polymers, nonionic, anionic, or amphoteric surfactants. 
     
     
       28. The dialysis apparatus of claim 27 wherein said hydrophilic polymers comprise polyvinylpyrolidone. 
     
     
       29. The dialysis apparatus of claim 16 wherein the housing is a material selected from polycarbonate, polyethylene or polypropylene. 
     
     
       30. The dialysis apparatus of claim 16 wherein the housing is polycarbonate.