Circulation half-life

Steroid and thyroid hormones are minimally soluble in the blood. Binding to plasma proteins renders them water soluble and facilitates their transport. Protein binding also prolongs the circulating half-life of these hormones. Because they are lipid soluble, they cross cell membranes easily. As the blood flows through the kidney, these hormones would enter cells or be... 

Insertion of PEG-lipid into conventional liposome phospholipid bilayer had substantially increased their circulation half-life. Pharmacokinetic of PEGylated liposome is clearly modified by the presence of the PEG-lipid extended circulation time was reported as reviewed (4). 

Pharmacokinetics Epoetin alfa IV is eliminated via first-order kinetics with a circulating half-life of 4 to 13 hours in patients with CRF. Within the therapeutic dosage range, detectable levels of plasma erythropoietin are maintained for at least 24 hours. After subcutaneous administration of epoetin alfa to patients with CRF,... 

Oxytocin is administered intravenously for initiation and augmentation of labor. It also can be administered intramuscularly for control of postpartum bleeding. Oxytocin is not bound to plasma proteins and is eliminated by the kidneys and liver, with a circulating half-life of 5 minutes. 

Our laboratory has for a number of years championed the use of the plasma protein albumin as an effective carrier to protect enzymes for use in enzyme-replacement therapy. Albumin is the moat abundant plasma protein and has a circulation half-life of as much as 6(1-72 hours. It has both hydrophilic and... 

F. F. Davis, G. M. Kara, M. L. Nucd, and A. Abuchowsld. Reduction of unmunogenkity and extension of circulating half-life of peptides and proteins. Peptide and Protein Drug Delivery (V. H. L. Lee, ed,). Marcel Dekker, New York, 1991, p. 83 L... 

The major function of the parathyroid hormone (PTH parathormone) is to regulate the concentration of extracellular calcium. PTH is heterogeneous and circulates as an intact polypeptide and as fragments. The major circulating biologically active peptide is intact PTH, which is rapidly cleared from the circulation (half-life less than 10 min). The N-terminal portion is responsible for its biologic activity. 

Potency/biological activity Pharmacokinetic profile Absorption time from tissue vs. IV Circulating half-life Distribution and elimination kinetics Toxicological profile Immunogenic potential Patient population characteristics Disease state Pathophysiology Age... 

Therefore, similar to POE, the PEG-PE is also incorporated as a coemulsifier into emulsions (termed PEGylated emulsion) to augment its circulation half-life... 

Bioactivity Pharmacokinetics Signal transduction Bioactivity Circulating half-life... 

In many cases, the role of many post-translational modifications is not well understood, but in some cases they have been found to be required for the biological activity of the protein molecules. In some cases where the enzymatic or co-factor activity of a protein is unaffected by the lack of a specific post-translational modification, it has been found to impact properties such as stability and circulating half-life. Thus, while the lack of glycosylation of many proteins is without influence on their functionality, they become unstable and are cleared faster from circulation. 

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