Bioavailability of potassium from controlled-release tablets with and without water loading

Area of Science:

• Pharmacokinetics and Drug Delivery
• Nutritional Science
• Clinical Pharmacology

Background:

• Controlled-release potassium supplements are crucial for managing hypokalemia.
• Understanding the bioavailability of different potassium formulations is essential for effective therapeutic strategies.
• Previous studies have highlighted the impact of dietary intake and hydration on potassium excretion patterns.

Purpose of the Study:

• To compare the relative potassium bioavailability between a controlled-release multiple-units tablet (Kalinorm) and a single-unit tablet (Slow-K).
• To investigate the influence of water loading on urinary potassium excretion and bioavailability measurements.
• To provide recommendations for optimizing study designs for potassium excretion research.

Main Methods:

• A comparative bioavailability study involving 13 healthy volunteers on a controlled low-potassium diet (<30 mmol/day).
• Administration of a single dose of 32 mmol potassium via Kalinorm and Slow-K formulations, with and without water loading.
• Monitoring of urinary potassium excretion as the primary indicator of potassium absorption and availability.

Main Results:

• Both Kalinorm and Slow-K exhibited equivalent extent of potassium bioavailability.
• Water loading did not significantly alter the overall potassium absorption from either formulation.
• Urinary potassium excretion patterns were influenced by the experimental procedure, particularly water loading.

Conclusions:

• Kalinorm and Slow-K provide comparable potassium bioavailability.
• Water loading should be avoided in studies measuring urinary potassium excretion rates to prevent confounding results.
• Careful control of dietary potassium and hydration is recommended for accurate pharmacokinetic assessments of potassium supplements.