Immunoassays for everolimus

A method of determining the concentration of everolimus in a sample, said method comprising the steps of:

• (a) providing a first everolimus compound comprising everolimus coupled to a detectable label via a first linker;
• (b) providing an anti-everolimus antibody produced using a second everolimus compound comprising everolimus coupled to an antigenic carrier via a second linker, wherein at least the structure of the first linker is different from said second linker, or said first linker is attached to everolimus in the first everolimus compound at a different position than the position that the second linker is attached to everolimus in the second everolimus compound;
• (c) combining said sample, said anti-everolimus antibody and said first everolimus compound, the everolimus in said sample competing with said first everolimus compound for binding to said anti-everolimus antibody;
• and
• (d) determining the concentration of everolimus in the sample by measuring the amount of said first everolimus compound not bound to said antibody by detection of said label.

A kit for determining the concentration of everolimus in a sample, said kit comprising:

• a first everolimus compound comprising everolimus coupled to a detectable label via a first linker;
• and
• an anti-everolimus antibody;
• wherein said anti-everolimus antibody is produced using a second everolimus compound comprising everolimus coupled to an antigenic carrier via a second linker,
• wherein at least the structure of the first linker is different from said second linker, or said first linker is attached to everolimus in the first everolimus compound at a different position than the position that the second linker is attached to everolimus in the second everolimus compound;
• and
• wherein said first everolimus compound is capable of competing with the everolimus in said sample for binding to said anti-everolimus antibody.