Comparative pharmacokinetic study of trimethadione and dimethadione for lysis of pancreatic stones.

In order to investigate the biological equivalence of dimethadione (DMO) and its precursor trimethadione (TMO), comparative pharmacokinetic studies were performed in 6 beagle dogs. DMO and TMO powder was given orally at the same molar dose of 1.0g and 1.11 g (7.7mM), respectively. Plasma concentration of DMO and TMO was determined at an appropriate interval. Four pharmacokinetic parameters were calculated from the plasma concentration-time curves of DMO and TMO; the peak plasma concentration (Cmax), the time to the peak concentration of Cmax (Tmax), the area under the plasma concentrationtime curve (AUC), and the biological half-life (t1/2). In the plasma concentration-time curve of DMO, Tmax after oral administration of TMO was longer than that after administration of DMO. This resulted from the presence of the conversion process of TMO to DMO in the body, because of the very short Tmax observed in the plasma concentration-time curve of TMO. Cmax, AUC and t1/2 did not differ significantly between the drugs. The results obtained indicate that TMO is biologically equivalent to DMO in regard to plasma concentration of DMO.