Methods of determining active levels of drugs in fluid samples

Abstract

Methods for determining the presence and level of active drugs in fluid samples are provided. Advantageously, entire families or classes of drugs can be tested for in one test by identifying the enzyme or receptor upon which members of that drug family act and measuring enzyme activity levels or binding activity levels of receptors. Methods for establishing standard activity levels of these drugs based upon results from samples having known quantities of drug therein are also provided.

1 . A method of determining the presence of an active drug in a fluid sample, said drug in its active state capable of binding with a selected receptor and inhibiting binding of a target ligand to said receptor, said method comprising the steps of:
 providing a first fluid sample, said sample including said receptor;   adding a quantity of said target ligand to said first fluid sample;   measuring the binding activity level of said ligand to said receptor; and   determining the presence of said active drug by said measured binding activity level.   
   
   
       2 . The method of  claim 1 , further comprising the step of comparing said measured binding activity level with a standard binding activity level. 
   
   
       3 . The method of  claim 2 , said standard binding activity level representing the binding activity level of said receptor with a known quantity of said target ligand. 
   
   
       4 . The method of  claim 1 , further comprising the step of correlating said measured binding activity level with the concentration of said active drug. 
   
   
       5 . The method of  claim 4 , said correlating step including the step of comparing said measured binding activity level with a standard binding activity level. 
   
   
       6 . The method of  claim 5 , said standard binding activity level representing the binding activity level of said receptor with a known quantity of said target ligand. 
   
   
       7 . The method of  claim 1 , said measured binding activity level decreasing when said active drug is present. 
   
   
       8 . The method of  claim 1 , said measured binding activity level increasing as the level of active drug in said sample decreases. 
   
   
       9 . The method of  claim 1 , said measured binding activity level being inversely proportional to the level of said active drug in said sample. 
   
   
       10 . The method of  claim 1 , said drug being selected from the group consisting of beta-blocking drugs. 
   
   
       11 . The method of  claim 10 , wherein said beta-blocking drugs are selected from the group consisting of atenolol, propranolol, metoprolol, nadolol, pindolol, timolol, cavediol, and sotalol.