Single-dose kinetics and bioavailability of sodium-hydrogen divalproate

Valproic acid is a widely used antiepileptic drug, but its formulations can cause gastrointestinal irritation. Researchers have explored alternative delivery methods to improve tolerability. Prior studies established that valproic acid is absorbed from the gastrointestinal tract and has predictable elimination kinetics. However, the bioavailability of new formulations remains unclear. No prior work had resolved whether enteric-coated tablets of sodium-hydrogen divalproate could match traditional sodium valproate preparations. This uncertainty drove the need for a direct comparison of these formulations. The study aimed to address this gap by evaluating absorption and elimination parameters. Understanding these differences could inform clinical choices for patients. The focus was on single-dose kinetics to assess initial drug behavior. This study sought to clarify the role of formulation in drug performance.

The study aimed to compare the bioavailability and single-dose kinetics of sodium-hydrogen divalproate and sodium valproate in healthy volunteers. Researchers wanted to determine if the new formulation offers advantages in absorption and tolerability. The goal was to assess whether SHD provides faster absorption without compromising safety. The study design focused on a crossover comparison to minimize variability. This approach allowed direct comparison of the two formulations. The primary outcome was the area under the concentration-time curve. Secondary outcomes included peak concentration and time to peak. The study aimed to inform future clinical use of SHD.

The study used a single-dose, double-blind, crossover design. Fourteen healthy volunteers received either SHD or sodium valproate. Blood samples were collected up to 48 hours post-dose. Serum valproic acid concentrations were measured via gas chromatography. The AUC was calculated for each formulation. Elimination parameters like half-life and clearance were estimated. Tmax and Cmax were compared between groups. Statistical analysis confirmed the significance of differences.

The AUC for SHD was 2,925.0 ± 189.1 h·μmol/L. For sodium valproate, it was 2,816.2 ± 162.2 h·μmol/L. These values were not statistically different. SHD showed a faster absorption with a Tmax of 2.37 hours. Sodium valproate had a Tmax of 3.23 hours. SHD reached a higher peak concentration of 192 μmol/L. Sodium valproate reached 176 μmol/L. Both differences were statistically significant (p < 0.01). Elimination parameters were similar between the two formulations.

The study found that SHD and sodium valproate have similar bioavailability. Both formulations show comparable elimination kinetics. SHD provides faster absorption and higher peak concentrations. These differences were statistically significant. The authors propose that SHD may offer improved tolerability. The enteric coating may reduce gastrointestinal irritation. The results suggest SHD could be a viable alternative to sodium valproate. No essential differences in elimination were observed.