Compounds and Methods for Use in Detecting Gabapentin

Abstract

Compounds and methods for use in detecting gabapentin in a sample suspected of containing gabapentin are disclosed. Gabapentin derivatives are used to produce gabapentin conjugates. A gabapentin-immunogenic carrier conjugate may be used as an immunogen for the preparation of an anti-gabapentin antibody. A gabapentin-detectable label may be used in a signal producing system in gabapentin assays.

1 . A compound having the structure: 
       
         
           
           
               
               
           
         
         wherein: 
         R 1 , R 2 , or R 3  is —X—W-L-Z,
 when R 1  is —X—W-L-Z, X is NH, and R 2  is —OH, and R 3  is —H, 
 when R 2  is —X—W-L-Z, X is NH, R 1  is —NH 2 , and R 3  is —H, and 
 when R 3  is —X—W-L-Z, X is a heteroatom or lower alkyl group, R 1  is —NH 2 , and R 2  is —OH; 
 
         W is a lower alkyl group or a carbonyl group; 
         L is a linker or at least one bond between W and Z; and 
         Z is H, an alkyl group, a reactive functional group capable of reacting with a reactive partner to form a covalent bond, or a moiety of interest, 
         or a salt thereof. 
       
     
     
         2 . The compound of  claim 1 , wherein said linker comprises 0 to 40 carbon atoms and 0-6 heteroatoms. 
     
     
         3 . The compound of  claim 2 , wherein W is a lower alkyl and said linker is selected from the group consisting of:
 —(CH 2 ) n C(O)—;   —C(O)(CH 2 ) n —;   —C(O)(CH 2 ) n NH—C(O)—;   —C(O)(CH 2 ) m NH—C(O)(CH 2 ) n —;   —(CH 2 ) n SCH 2 C(O)—;   —(CH 2 ) m SCH 2 C(O)(CH 2 ) n —;   —(CH 2 ) m C(O)NH(CH 2 ) n —;   —(CH 2 ) n NH—C(O)—;   —(CH 2 ) m NH—C(O)(CH 2 ) n —;   —C(O)—(CH 2 ) n —; and   —(CH 2 ) n —, and   wherein m, n, o, and p are independently selected from an integer from 0 to 10.   
     
     
         4 . The compound of  claim 2 , wherein W is a carbonyl and said linker is selected from the group consisting of:
 —(CH 2 ) n C(O)—;   —(CH 2 ) n SCH 2 C(O)—;   —(CH 2 ) m SCH 2 C(O)(CH 2 ) n —;   —(CH 2 ) m C(O)NH(CH 2 ) n —;   —(CH 2 ) n NH—C(O)—;   —(CH 2 ) m NH—C(O)(CH 2 ) n —; and   —(CH 2 ) n —, and   wherein m, n, o, and p are independently selected from an integer from 0 to 10.   
     
     
         5 . The compound of  claim 1 , wherein W is a lower alkyl group and the lower alkyl group is a methyl group. 
     
     
         6 . The compound of  claim 1 , wherein said reactive functional group is selected from the group consisting of halogen, OH, SH, NH 2 , O-lower alkyl, epoxy, S-acyl, carboxyl, maleimidyl, haloacetamide, hydroxysuccinimidyl, succinimidyl, carbonate, anhydride and imidate. 
     
     
         7 . The compound of  claim 6 , wherein said halogen is Br or I. 
     
     
         8 . The compound of  claim 1 , having the structure: 
       
         
           
           
               
               
           
         
         wherein W, L, and Z are as defined in  claim 1 . 
       
     
     
         9 . The compound of  claim 8 , wherein Z is SH or Br. 
     
     
         10 . The compound of  claim 8 , wherein Z is a reactive functional group, and wherein —W-L-Z is a straight or branched alkyl chain. 
     
     
         11 .- 54 . (canceled) 
     
     
         55 . An isolated antibody comprising a binding fragment that specifically binds a gabapentin conjugate, wherein the gabapentin conjugate has the structure: 
       
         
           
           
               
               
           
         
         wherein: 
         R 1 , R 2 , or R 3  is —X—W-L-Z, and
 when R 1  is —X—W-L-Z, X is NH, and R 2  is —OH, and R 3  is —H, 
 when R 2  is —X—W-L-Z, X is NH, R 1  is —NH 2 , and R 3  is —H, and 
 when R 3  is —X—W-L-Z, X is a heteroatom or lower alkyl group, R 1  is —NH 2 , and R 2  is —OH; 
 
         W is a lower alkyl group or a carbonyl group; 
         L is a linker or at least one bond between W and Z; and 
         Z is the enzyme. 
       
     
     
         56 . The antibody of  claim 55 , wherein the linker comprises 0 to 40 carbon atoms and 0-6 heteroatoms. 
     
     
         57 . The antibody of  claim 55 , wherein W is a lower alkyl and the linker is selected from the group consisting of:
 —(CH 2 ) n C(O)—;   —C(O)(CH 2 ) n —;   —C(O)(CH 2 ) n NH—C(O)—;   —C(O)(CH 2 ) m NH—C(O)(CH 2 ) n —;   —(CH 2 ) n SCH 2 C(O)—;   —(CH 2 ) m SCH 2 C(O)(CH 2 ) n —;   —(CH 2 ) m C(O)NH(CH 2 ) n —;   —(CH 2 ) n NH—C(O)—;   —(CH 2 ) m NH—C(O)(CH 2 ) n —;   —C(O)—(CH 2 ) n —; and   —(CH 2 ) n —, and   wherein m and n are independently selected from an integer from 0 to 10.   
     
     
         58 . The antibody of  claim 57 , wherein the linker is —(CH 2 ) m NH—C(O)(CH 2 ) n —. 
     
     
         59 . The antibody of  claim 55 , wherein W is a carbonyl and said linker is selected from the group consisting of:
 —(CH 2 ) n C(O)—;   —(CH 2 ) n SCH 2 C(O)—;   —(CH 2 ) m SCH 2 C(O)(CH 2 ) n —;   —(CH 2 ) m C(O)NH(CH 2 ) n —;   —(CH 2 ) n NH—C(O)—;   —(CH 2 ) m NH—C(O)(CH 2 ) n —; and   —(CH 2 ) n —, and   wherein m and n are independently selected from an integer from 0 to 10.   
     
     
         60 . The antibody of  claim 55 , wherein W is a lower alkyl group and the lower alkyl group is a methyl group. 
     
     
         61 . The antibody of  claim 55 , having the structure: 
       
         
           
           
               
               
           
         
         wherein W, L and Z are as defined in  claim 55 . 
       
     
     
         62 . The antibody of  claim 55 , having the structure: 
       
         
           
           
               
               
           
         
         wherein W, L, and Z are as defined in  claim 55 . 
       
     
     
         63 . The antibody of  claim 55 , having the structure: 
       
         
           
           
               
               
           
         
         wherein W, L and Z are as defined in  claim 55 . 
       
     
     
         64 . The antibody of  claim 55 , wherein said antibody is selected from a Fab, Fab′, F(ab′)′2, Fv fragment, and a single-chain antibody. 
     
     
         65 . The antibody of  claim 55 , wherein the antibody is a polyclonal antibody. 
     
     
         66 . The antibody of  claim 55 , wherein the antibody is a monoclonal antibody. 
     
     
         67 . The antibody of  claim 55 , wherein the enzyme is a glucose-6-phosphate dehydrogenase (G6PDH). 
     
     
         68 . The antibody of  claim 67 , wherein the G6PDH comprises at least one cysteine per subunit, wherein the cysteine is not native to a naturally-occurring G6PDH. 
     
     
         69 . The antibody of  claim 55 , wherein said enzyme is selected from alkaline phosphatase, β-galactosidase and horseradish peroxidase. 
     
     
         70 . The antibody of  claim 55 , wherein the antibody is non-human. 
     
     
         71 . The antibody of  claim 55 , wherein the antibody is derived from a rabbit. 
     
     
         72 . The antibody of  claim 55 , wherein the antibody is a recombinant antibody. 
     
     
         73 . The antibody of  claim 55 , wherein the antibody is present in a biological sample. 
     
     
         74 . The antibody of  claim 73 , wherein the biological sample is a blood sample.