• Maximum Plasma Concentration (Cmax) [ Time Frame: serial pharmacokinetic plasma concentrations were drawn prior to dose administration (0 hour) and at 0.33, 0.67, 1, 1.33, 1.67, 2, 2.33, 2.67, 3, 3.5, 4, 4.5, 5, 6, 8, 12, 18, 24, 36, 48, 60 and 72 hours after drug administration. ] [ Designated as safety issue: No ]
  
• Area Under the Concentration Versus Time Curve From Time 0 to Time t [AUC(0-t)] [ Time Frame: serial pharmacokinetic plasma concentrations were drawn prior to dose administration (0 hour) and at 0.33, 0.67, 1, 1.33, 1.67, 2, 2.33, 2.67, 3, 3.5, 4, 4.5, 5, 6, 8, 12, 18, 24, 36, 48, 60 and 72 hours after drug administration. ] [ Designated as safety issue: No ]
  
• Area Under the Concentration Versus Time Curve From Time 0 Extrapolated to Infinity [AUC(0-∞)] [ Time Frame: serial pharmacokinetic plasma concentrations were drawn prior to dose administration (0 hour) and at 0.33, 0.67, 1, 1.33, 1.67, 2, 2.33, 2.67, 3, 3.5, 4, 4.5, 5, 6, 8, 12, 18, 24, 36, 48, 60 and 72 hours after drug administration. ] [ Designated as safety issue: No ]
  

The purpose of this study is to compare the bioequivalence of a test formulation of primidone tablets to an equivalent oral dose of the commercially available Mysoline® (primidone tablets) in adult subjects under fasting conditions.

Twenty-two healthy, non-smoking, non-obese male and female volunteers at least 18 years of age will be randomly assigned in a crossover fashion to receive each of two primidone dosing regimens in sequence with a 14 day washout period between dosing periods. On the morning of Day 1, after an overnight fast of at least 10 hours, subjects will receive either a single oral dose of the test formulation, primidone (1 x 50 mg tablet) or a single oral dose of the reference formulation, Mysoline® (1 x 50 mg tablet). After a 14 day washout period, on the morning of Day 15 after an overnight fast, subjects will receive the alternate regimen. Blood samples will be drawn from all participants before dosing and for 72 hours post dose at times sufficient to adequately define the pharmacokinetics of primidone. A further goal of this study is to evaluate the safety and tolerability of this regimen in healthy volunteers. Subjects will be monitored throughout the confinement portion of the study for adverse reactions to the study drugs and/or procedures. Blood pressure and heart rate will be obtained prior to dosing and at 3, 4, 6, 24 and 72 hours post-dose. All adverse events whether elicited by query, spontaneously reported or observed by clinic staff will be evaluated by the investigator and reported in the subject's case report form.