Pharmacology Essay Example | Topics and Well Written Essays - 3000 words

Pharmacology - Essay Example reaches the targeted site, while the remaining fraction of the drug interacts with other sites, with consequences of inefficient drug delivery and undesirable side effects. Insufficient aqueous solubility and protein binding characteristics of that inhibit crossing blood brain barriers are two examples of the manner in which the relevance of some drugs in clinical therapeutics gets limited. It is against this background that pro-drugs and their utility in overcoming the limitations of bioavailability and pharmacokinetics profiles has become a significant subject of study in pharmacology (Shek, 1994). A look at the history of pro-drugs shows that understanding of pro-drugs and their pharmaco-kinetics in the human body came more as a result of after the introduction of the drugs for therapeutic purposes. The introduction of phenacetin as a therapeutic agent dates back to 1887, but it took till 1949 for the realization that paracetamol was the active metabolite of phenacetin, which resulted in the gradual erosion of phenacetin as a therapeutic agent to be replaced by paracetamol, demonstrating that many of the pro-drugs result from metabolism in the human body. (Pleuvry, 2006). This understanding of the possibility of enzymatic action to create active therapeutic agents has now become the basis of overcoming the problems of potential drug candidates demonstrating poor therapeutic effects, because of poor bioavailability and pharmacokinetic profiles. Kratz et al, 2008, define pro-drugs as â€Å"derivatives of a drug that are metabolized or activated in the body to release or generate the active drug – if possible at the site of action†. Thus pro-drugs are chemically modified versions of the pharmaceutical agent that needs to undergo a transformation in vivo for the release of the active drug. This feature of pro-drugs is employed to enhance the bioavailability and pharmacokinetic properties of pharmacologically potent compounds. In a majority of the cases