Prodrugs chemical definition

A prodrug by definition is inactive or much less active and has to be converted to the active drug within the biological system. There are a variety of mechanisms by which a prodrug can be activated. These include metabolic activation mediated by enzymes present in the biological system as well as the less common, simple chemical means of activation such as hydrolysis. 

V. J. Stella, Prodrugs An overview and definition, in Prodrugs in Novel Drug Delivery Systems (T. Higuchi and V. Stella, eds.), American Chemical Society, Washington, DC, 1975, p. 1. 

Stella, V. Prodrugs an overview and definition. In Prodrugs as Novel Drug Delivery Systems (Higuchi, T., Stella, V., Eds), Vol. 14. American Chemical Society Washington, DC, 1975, pp. 1—115. 

In its Notice on "Studies of Prolonged-Action Forms in Man" dated 1987 09) the EC introduces the term of active principle presented in "pharmaceutical forms." This concept may apply to prodrugs, but only indirectly because the substance contained as such in the pharmaceutical form is not exactly the active principle. Similarly, in the council recommendation of 1987 on Investigation on Bioavailability (20), the terms active drug ingredient or therapeutic moiety of a drug are used to define the chemical species that should be measured. Finally, in a newer definition of bioavailability, the term active substance is used (21). 

Synthesis and antimicrobial activity of 3-formyl analogs of norfloxacin, ciprofloxacin, and pefloxacin have been reported [93]. These studies have shown definitive evidence that the 3-formyl analogs of quinolones function as prodrugs and are oxidized in vivo to carboxylic acids. The higher bioavailability of formyl derivatives may be due to a change in physical and chemical properties by the lack of their amphoteric nature, compared to the parent zwitterionic compounds. 

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