Tacrolimus standard and methods of using same
A composition and kit useful as a tacrolimus standard solution for immunoassays, and methods for making and using same. The composition and kits include a known amount of tacrolimus or a derivative thereof, and a non-specific protein capable of forming a complex with the tacrolimus or derivative thereof. The standard solution may be used to generate calibration curves for an immunoassay or to check the precision of an analytical instrument.
1. A composition suitable for use as a standard in an assay, comprising:
a solution having a known amount of tacrolimus or a derivative thereof and a protein non-specific for tacrolimus and capable of forming a soluble complex with the tacrolimus or the derivative thereof, the protein being at least 95% fatty acid free and the ratio of non-specific protein to tacrolimus being in the range of 25,000:1 to 1000:1 on a weight basis, the solution further comprising a polyoxylated caster oil in an amount of 0.01% to 0.5% by weight.
2. The composition of claim 1 , wherein the solution comprises an aqueous solution and the complex is water soluble.
3. The composition of claim 1 , wherein the solution is free of alkanol solvents.
4. The composition of claim 1 , wherein the solution is free of methanol.
5. The composition of claim 1 , wherein the solution is free of proteins capable of specifically binding tacrolimus.
6. The composition of claim 1 , wherein the protein comprises albumin.
7. The composition of claim 1 , wherein the albumin comprises fatty acid free bovine serum albumin.
8. The composition of claim 1 , further comprising a hemolysate.
9. The composition of claim 1 , further comprising a label capable of forming a complex with an antibody and suitable for producing a detectable signal.