Preparation of dried synthetic prothrombin time reagents
First Claim
1. A method for preparing a non-lyophilized air dried prothrombin time reagent used for determining prothrombin time, the method comprising the steps of:
- combining a recombinant fusion protein of bacterial thioredoxin and rabbit brain tissue factor with a mixture of synthetic phospholipids in an amount sufficient to activate said protein; and
air-drying said protein and mixture combination at a temperature above about 10°
C. thereby forming the reagent;
wherein the air dried reagent remains stable for at least 2 weeks at 37°
C.
5 Assignments
0 Petitions
Accused Products
Abstract
A method for preparation of an air-dried prothrombin time (PT) reagent which uses a recombinant protein and synthetic phospholipids is described. The source for the recombinant protein is rabbit brain, and the phospholipids employed are palmitoyloleoylphosphatidylcholine (POPC) and palmitoyloleoylphosphatidylserine (POPS). The particular formulation buffer used to dilute the lipidated tissue factor provides a reagent that is dried without lyophilization and remains stable for at least 2 weeks at 37 C. A method for preparing the improved PT reagent and a method of using the reagent to analyze blood PT is also provided.
16 Citations
19 Claims
-
1. A method for preparing a non-lyophilized air dried prothrombin time reagent used for determining prothrombin time, the method comprising the steps of:
-
combining a recombinant fusion protein of bacterial thioredoxin and rabbit brain tissue factor with a mixture of synthetic phospholipids in an amount sufficient to activate said protein; and
air-drying said protein and mixture combination at a temperature above about 10°
C. thereby forming the reagent;
wherein the air dried reagent remains stable for at least 2 weeks at 37°
C.- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
-
-
10. A method of preparing a non-lyophilized air dried reagent which is used for determining prothrombin time, the method comprising the steps of:
-
adding synthetic phospholipids consisting of palmitoyloleoyl-phosphatidylcholine and palmitoyloleoylphosphatidylserine in a molar ratio range of 6;
4 to 8;
2 respectively to a solution containing an antioxidant, a buffer, a salt, an amino acid chelating agent, a detergent, and a humectant;
adding a recombinant fusion protein of bacterial thioredoxin and recombinant rabbit brain tissue factor to said phospholipid solution;
incubating said protein solution for a selected time at a selected temperature to form a homogeneous mixture;
dialyzing the mixture of lipid and tissue factor in a selected dialysis medium to remove said detergent and to form lipid vesicles having said tissue factor inserted therein;
diluting the lipidated tissue factor with a formulation buffer;
air-drying the formulated lipidated tissue factor at a temperature above about 10°
C. and at a selected relative humidity, wherein the air dried reagent remains stable for at least two weeks at 37°
C.- View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19)
-
Specification