Steady-state bioavailability of two clorazepate dipotassium dosage forms

Area of Science:

• Pharmacology
• Pharmaceutical Sciences
• Clinical Pharmacy

Background:

• Clorazepate dipotassium is a benzodiazepine commonly prescribed for anxiety and seizure disorders.
• Traditional administration involves multiple daily doses, potentially impacting patient adherence and therapeutic outcomes.
• Development of a once-daily dosage form aims to improve patient compliance and maintain consistent therapeutic drug levels.

Purpose of the Study:

• To evaluate the pharmacokinetic profile and bioavailability of a novel once-daily tablet formulation of clorazepate dipotassium.
• To compare the serum levels achieved by the new tablet formulation against conventional divided-dose capsule regimens.
• To assess the steady-state pharmacokinetics following multiple-dose administration of both formulations.

Main Methods:

• Single-dose administration of 22.5 mg clorazepate dipotassium as a tablet versus divided-dose capsules (7.5 mg every 6 hours).
• Pharmacokinetic analysis using a two-compartment open model with first-order absorption to determine serum half-life of nordiazepam.
• Multiple-dose, crossover study involving 14 days of administration to assess steady-state serum levels and bioavailability.

Main Results:

• The once-daily tablet produced intermediate peak serum levels compared to single and divided-dose capsules, with no significant impact on absorption extent.
• Nordiazepam, the active metabolite, exhibited a serum half-life of approximately 48 hours.
• Multiple-dose administration of the tablet and divided-dose capsules resulted in equivalent minimum steady-state serum levels (around 0.6 µg/mL) and AUC (0-24h).

Conclusions:

• The specially designed once-daily tablet formulation of clorazepate dipotassium achieves pharmacokinetic profiles comparable to a divided-dose capsule regimen.
• This new dosage form offers equivalent therapeutic exposure and improved convenience for patients requiring clorazepate dipotassium therapy.
• The study validates the use of a single daily dose for maintaining consistent therapeutic drug levels, enhancing patient adherence.