Plasma Protein Binding

Plasma protein binding reduces drug bioavailability and tissue penetration through reversible albumin and globulin binding. High protein binding limits free drug concentration. Albumin binding predominates for most drugs. Displacement from binding sites by concomitant medications increases free concentration. Disease-altered protein levels influence drug binding.

Protein binding quantitation guides dose predictions. Population variation explains interindividual pharmacokinetic differences. Regulatory submissions incorporate binding data. Therapeutic drug monitoring measures total drug accounting for binding. Post-approval monitoring confirms binding predictions.