T. Ueda, Shin'ichi Kobayashi, H. Yasuhara
Sep 30, 1991
Citations
0
Influential Citations
0
Citations
Quality indicators
Journal
Rinsho Yakuri\/japanese Journal of Clinical Pharmacology and Therapeutics
Abstract
Pirmenol is a newly developed antiarrythmic drug. The binding of pirmenol to albumin, AAG, in vitro or in vivo was studied using the ultrafiltration method. Regarding the in vitro study, pirmenol bound to a single class binding site of purified human serum AAG (AAG-P), which was characterized by a higher affinity (Kd was 1.14×10-6M) than that of human serum albumin (HSA, Kd was not detectable). The percent of binding of pirmenol to AAG-P and HSA was mainly related to the concentration of AAG-P. Regarding the in vivo study: a single dose of 75, 100, and 150mg, of pirmenol was administered to 16 patients with ventricular arrythmia. The peak plasma concentrations were 0.606±0.32, 0.875±0.44, or 1.29±0.49μg/ml, respectively. The binding percent was 63-87% in the plasma and the relationship between the binding/free pirmenol concentration ratio and the AAG concentration in the plasma was shown to be the relation constant 0.48 with P<0.01. The plasma concentration of AAG in these patients was almost within normal range and also the pirmenol concentration in plasma was lower; therefore, the relation constant was a low value. On the other hand, plasma concentrations of AAG in 174 volunteers (21-98yrs) showed a good corelation between age and plasma concentrations of AAG (r=0.78, P<0.01). These data suggest that the free fraction of pirmenol in plasma may be influenced by pathological conditions and age, due to a change in plasma AAG concentration.