Protein binding of nifedipine

Area of Science:

• Pharmacology
• Biochemistry
• Clinical Chemistry

Background:

• Nifedipine is a widely used calcium channel blocker.
• Understanding drug-protein interactions is crucial for pharmacokinetics and pharmacodynamics.
• Albumin and alpha 1-acid glycoprotein (AAG) are major drug-binding proteins in human serum.

Purpose of the Study:

• To quantify the protein binding of nifedipine in human serum and purified protein solutions.
• To identify the primary protein responsible for nifedipine binding in serum.
• To investigate the relationship between AAG concentration and nifedipine binding.

Main Methods:

• Ultrafiltration technique was employed to measure protein binding.
• Nifedipine binding was assessed in serum from healthy volunteers.
• Binding was also evaluated in solutions of human albumin and alpha 1-acid glycoprotein (AAG) at varying concentrations.

Main Results:

• Nifedipine exhibited extensive binding in human serum (mean fraction bound 0.992).
• Binding in albumin solution (40 g/L) was comparable to serum (mean fraction bound 0.970), indicating albumin as a major binding protein.
• Nifedipine binding to AAG was concentration-dependent, increasing from 0.514 to 0.755 with AAG concentrations from 50 to 150 mg%.

Conclusions:

• Human serum albumin is the principal protein responsible for nifedipine binding.
• Alpha 1-acid glycoprotein contributes to nifedipine binding, with increased binding at higher AAG concentrations.
• Nifedipine protein binding demonstrates a linear relationship across all tested protein concentrations.