Table 1

Inhibition of tolperisone consumption and M1 formation with chemical inhibitors

Inhibitor Concentration (μM) 1-aInhibition % 1-b
Inhibition of intrinsic Clearance of TolperisoneInhibition of M1 Formation
Quinidine 1027 ± 6.677 ± 0.3
Ketoconazole 1015 ± 13.124 ± 1.6
Furafylline 2014 ± 4.025 ± 3.2
Sulfaphenazole 20019 ± 9.328 ± 0.9
S-mephenytoin 20022 ± 5.616 ± 1.6
SKF-525A 10039 ± 7.679 ± 0.4
SKF-525A 100061 ± 9.41001-c
1-aminobenzotriazole 100043  ± 7.4100
1-benzylimidazole 100049  ± 2.5100 
  • 1-a The concentration of each inhibitor was chosen so as to represent the diagnostic value (i.e. the maximal specificity for the given P450). Tolperisone was used at 5 μM.

  • 1-b The results are expressed as the mean of three determinations ± S.D. except for furafylline, where six determinations were done.

  • 1-c 100% inhibition using 1000 μM SKF-525A, ABT and BI means that M1 metabolite could not be detected at all.