Protein molecules clearance mechanisms

Absorption of the protein and peptide molecules delivered to the respiratory tract competes against various other clearance mechanisms. When a particle containing a therapeutic substance is deposited in the... 

The preclinical pharmacokinetics of protein pharmaceuticals is distinctively different from small-molecule drugs. The phase I and phase II metabolizing enzymes, for example, the cytochrome P450 and glucoronosyl transferases, which play dominant roles in the metabolism of small-molecule drugs, are not significantly involved in protein metabolism. Instead, because all protein pharmaceuticals invariably share a common polypeptide backbone, they are susceptible to proteolysis as a clearance mechanism. However, the disposition, pharmacokinetics. 

Current opinion suggests that after emptying into the bloodstream, drugs associated with lymph lipoproteins equilibrate across the various plasma lipoprotein and protein fractions and take on the same clearance properties as drug introduced into the systemic circulation by way of the portal blood. The data of Haus et al. suggest that this is an oversimplification and that the mechanism of interconversion and interaction of dmg molecules between lymph and plasma lipoproteins is not clear [123],... 

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