Biologies and small molecules

Overall, there are some profound differences between the pharmacokinetic (PK) behavior of biologies and small molecules. Table 41.1 summarizes the major differences between these two broad classes of molecules. When evaluating the PK behavior of any protein, it is important to understand the biology and the pharmacology of the system that the therapeutic biologic is acting on in order to anticipate the expected covariates and behavior of the drug. 

For stability studies, it is likely several of these types of assays will be used, each providing information on different characteristics of the molecule or information on the different types of degradation pathways. It is common that many tests (relative to what is performed for small molecules) are performed to characterize a biologic substance or product to give assurance of potency, purity, and quality. Table 17.1 (see section 17.3 ) gives a quick comparison of the differences between a biologic and small molecule drug product. 

Samanen J. (2013) Similarities and differences in the discovery and use of biopharmaceuticals and small molecule chemo-therapeutics. In Ganellin CR, Roy Jefferis R, Roberts S, editors. Introduction to biological and small molecule drug research and development. Elsevier, p 161-200. 

PYRROLE NATURAL PRODUCTS AND MATERIALS 5.2.4.1 Natural Products and Biologically Active Small Molecules... 

Improving the electroanalytical sensitivity and selectivity for small biological and pharmic molecules with carbon nanotubes... 

Iron is the second most abundant metal on the planet. Probably due to its abundance, virtually all forms of life have evolved to depend on iron to support essential biological processes, which include a range of catalytic processes, electron transfer, and small molecule storage and transport (1). However, ferric... 

Ion-exchange resins are cross-linked polymers which are typically polystyrene, cellulose or agarose based. Polystyrene is hydrophobic in nature and useful for inorganic ions and small molecules while cellulose and agarose are hydrophilic and more useful for the larger, biologically important molecules, e.g. proteins and nucleic acids, which either would be adversely affected by a hydrophobic environment or could not gain access to the small pore structure. 

There are big molecules (proteins, nucleic acids) and small molecules (most of the rest). The really interesting stuff happens when big molecules and small molecules interact to produce some biological action. 

NMR is a powerful and versatile tool for structural studies of biological RNAs and complexes they form with other nucleic acids, proteins, and small molecules. The goal of these studies is to determine the role that structure and dynamics play in biological function. NMR has the capacity to determine high-resolution structures, as well as to map RNAiligand interfaces at low resolution. Most structures of RNA and RNA-ligand complexes are under 20 KDa in size however, recent advances allow for determination of solution structures of complexes up to 40 kDa. NMR can also probe dynamic motions in RNA on micro- to millisecond time scales. A number of biologically relevant internal motions such as... 

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