OBJECTIVE: This study was performed to investigate whether it is possible to use saliva instead of blood usually used for therapeutic drug monitoring (TDM) of disopyramide. METHODS: Six healthy male volunteers ingested 200 mg of disopyramide base, and the disopyramide concentrations in saliva and plasma (total and unbound) were determined by the HPLC. RESULTS: Disopyramide concentration-time profiles for the saliva were nearly equal to those for the plasma unbound concentrations. A large variation for absorption time of the drug was observed among the subjects. Disopyramide concentrations (Cs) in saliva did not correlated well with plasma total concentrations (Cp), r = 0.799, but did well with unbound concentrations (Cpu), r = 0.969, for the 3-12 h period on the elimination phase. The mean ratio of disopyramide concentrations in the saliva against the plasma unbound concentrations was almost constant (1.02(0.10), CV = 9.7%) for the period. The pharmacokinetic parameters (tmax, t1/2, AUC, AUMC and MRT values) for disopyramide calculated from the saliva data were nearly equal to those from the unbound data. CONCLUSION: Disopyramide concentrations in saliva correlated well with plasma unbound concentrations on the elimination phase.
OBJECTIVE: This study was performed to investigate whether it is possible to use saliva instead of blood usually used for therapeutic drug monitoring (TDM) of disopyramide. METHODS: Six healthy male volunteers ingested 200 mg of disopyramide base, and the disopyramide concentrations in saliva and plasma (total and unbound) were determined by the HPLC. RESULTS:Disopyramide concentration-time profiles for the saliva were nearly equal to those for the plasma unbound concentrations. A large variation for absorption time of the drug was observed among the subjects. Disopyramide concentrations (Cs) in saliva did not correlated well with plasma total concentrations (Cp), r = 0.799, but did well with unbound concentrations (Cpu), r = 0.969, for the 3-12 h period on the elimination phase. The mean ratio of disopyramide concentrations in the saliva against the plasma unbound concentrations was almost constant (1.02(0.10), CV = 9.7%) for the period. The pharmacokinetic parameters (tmax, t1/2, AUC, AUMC and MRT values) for disopyramide calculated from the saliva data were nearly equal to those from the unbound data. CONCLUSION:Disopyramide concentrations in saliva correlated well with plasma unbound concentrations on the elimination phase.