Discovery of new medicines

A number of early medicines, including morphine (analgesic) and quinine (antimalarial), were isolated from plants. Over the years the search for 

Other more recent examples of new receptor subtypes include neurokinin, melanocortin and somatostatin receptor subtypes. Neurokinins (substance P, neurokinin A and neurokinin B) act at three receptor subtypes NKj, NKj and NK,. Selective ligands are being explored for the treatment of pain, asthma, depression, etc. The natural melanocortic peptides are derived from the precursor peptide pro-opiomelanocortin 

Some of the recent information has shown that the five receptor subtypes may fall into two classes or groups. One class (SRIFj) appears to comprise SSTj, SSTj and SST, and the other class (SRIF ) consists of the other two recombinant receptor subtypes (SSTj and SSTJ.  

Currently the drug discovery process has progressed beyond the receptor stage and various steps that result from the interaction of the receptor with a specific ligand have been characterised. One of the more important processes, signal transduction, converts the external signals induced by hormones, growth factors, neurotransmitters and cytokines into specific 

Since the complete genome of Haemophilus influenzae was published, sequencing of genomes from a wide range of organisms, from bacteria to man, has continued apace. Initial sequencing and analysis of the human 

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In developed countries, the discovery of new medicines and their introduction in the existing health care system during the second part of the last century has dramatically improved health, reducing mortality and morbidity from many common diseases. The society in general have benefited from these advances through the regular access to the needed medicines in their health care system. However, in many developing countries the needed essential medicines are not always available, accessible and affordable to those in need. 

The discovery of new medicines and their introduction into the market will not optimally have positive impacts on health if the needed essential medicines are not available and affordable, if they are not of good quality and if they are not properly utilized by the health care providers and consumers. This chapter will highlight the issues related to commonly occurring problems in the area of medicines in developing countries, and relevant policies and programme to deal with them. In particular, the chapter will highlight the problems of access to... 

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