Pharmacokinetics of phenobarbital in the cat following multiple oral administration.

Phenobarbital was administered orally to seven healthy cats at a dose of 5 mg/kg once a day for 21 days. Serum phenobarbital concentrations were determined using a commercial immunoassay technique. A one-compartment model was used to describe the final elimination curve. The elimination half-life (t1/2 b) after the final day of treatment was 43.3 +/- 2.92 h. The large apparent volume of distribution of 695.0 +/- 43.9 mL/kg suggests that the drug was widely distributed within the body. The t1/2 b following multiple oral administration was significantly shorter than previously reported for a single oral dose of phenobarbital in the cat. Analysis of pharmacokinetic results after days 1 and 21 of treatment suggested that the elimination kinetics of phenobarbital did not change significantly with multiple oral administration. It appears that differences in elimination kinetics can exist between populations of cats. These differences emphasize the need for individual monitoring of cats receiving phenobarbital.     

Equatorial Undercurrent and Related Currents off Brazil in March and April 1963

In 1963, the source of the Equatorial Undercurrent appeared to be near 38 degrees W. This undercurrent was an equatorial extension of a narrow saline current setting east-southeast at the surface near 2 degrees N 42 degrees W. Near 380 degrees W, a retroverse branch of the Guiana Current also joined the Equatorial Undercurrent. Surface flow was easterly along all of the east-southeast current and the undercurrent observed. The subsurface-velocity maximum of the undercurrent was higher at 35 degrees W than at 38 degrees W.