Biopharmaceutics, Pharmacokinetics, and Pharmacodynamics of Biological Products

Our understanding about the science surrounding the biopharmaceutics (BP), pharmacokinetics (PK), and pharmacodynamics (PD) is well established, but that of biological products are now in an evolving phase. Here, we have summarized the role of BP, PK, and PD on the absorption, distribution, metabolism, and elimination (ADME) of biological products and the possible use of computational models in predicting these pharmaceutical parameters of biologics. Of the major biopharmaceutical properties that are a function of ADME of biological products are hydrophobicity or hydrophilicity, molecular weight (MW), three-dimensional structure, folding, misfolding, hydrodynamic diameters, and chemical stability. The rate of absorption of biologics that are administered by intramucular and subcutaneous (SC) injection is very slow because of lymphatic system distribution and absorption-limited elimination. Tissue distribution of biologics varies depending on the MW and properties of biological barriers. Biologics with MW below 60 kDa are generally eliminated via the renal route. Liver also plays a significant role in the elimination of biologics by metabolizing peptides and proteins, receptor mediated endocytosis, and nonselective pinocytosis. Depending on the type of biologics, PK of biologics may either follow target mediated drug disposition or nonlinear PK that can be studied using various computation models. Overall, BP, PK, and PD of biologics are often distinctly different from those of chemical drugs and that they vary depending on the type biologics such as therapeutic proteins vs. monoclonal antibodies (mAbs).