[Pharmacokinetics of colloidal bismuth subcitrate. Solution versus tablet]

Area of Science:

• Pharmacology
• Toxicology
• Drug Delivery

Background:

• Bismuth compounds are used for gastrointestinal disorders.
• Understanding the pharmacokinetics of different bismuth preparations is crucial for optimizing therapeutic outcomes and minimizing systemic exposure.
• Colloid bismuth subcitrate (CBS) is a commonly prescribed bismuth preparation.

Purpose of the Study:

• To investigate and compare the pharmacokinetics of colloid bismuth subcitrate (CBS) following administration of a solution versus a tablet formulation.
• To assess the systemic bismuth load and urinary excretion in healthy volunteers receiving different CBS preparations.

Main Methods:

• A pharmacokinetic study involving 12 healthy volunteers divided into two groups.
• Group 1 received 240 mg CBS solution twice daily (b.d.) for 2 weeks.
• Group 2 received 120 mg CBS tablets twice daily (b.d.) for 2 weeks, with both groups receiving a total daily dose of 480 mg CBS.

Main Results:

• Urinary bismuth excretion on days 7 and 14 was significantly lower with the CBS solution compared to the CBS tablet.
• Plasma AUC (area under the curve) after a single 240 mg dose was substantially lower for the solution (4.2 µg/mL·h) than the tablet (42.8 µg/mL·h).
• The study demonstrated a markedly lower systemic bismuth load with the CBS solution compared to the tablet formulation.

Conclusions:

• The formulation of colloid bismuth subcitrate significantly impacts its pharmacokinetic profile.
• CBS solution leads to a lower systemic bismuth exposure compared to CBS tablets.
• These findings suggest that CBS solution may be preferable for minimizing systemic bismuth accumulation.