What Is Medicinal Chemistry?

Medicinal Chemistry is a Chemistry-based discipline which encompasses: innovation; the discovery and development of new bioactive chemical entities (NCE); synthesis or molecular modification; isolation, identification and the structural elucidation of the main active elements of plants, animals or minerals; the description of the molecules from their atomic level (passing through the relationships between structure and properties) to their structural characteristics when interacting with biological targets of therapeutic interest; comprehension at the molecular level of the biochemical/pharmacological, toxicological and pharmacokinetic processes and the creation of relationships between chemical structure and pharmacological activity (SARs).

It is also implicitly related to the proposal and validation of mathematical models through studies of relationships between chemical structure and pharmacological and/or toxicological and/or pharmacokinetic activity.

Medicinal chemistry is, therefore, a hybrid subject operating together with other disciplines such as biophysics, molecular biology, biochemistry, clinical medicine, physical chemistry, physiology, neurobiology, pathology, biological chemistry, inorganic and organic chemistry, quantum chemistry, etc., within a trans- (on the insertion of one concept onto another), multi- (on the coexistence of multiples), and interdisciplinary (on the necessity of interfaces) aspects, in which all of the parts are equally fundamental.

At the beginning of the 20th century, the methods of discovery of new pharmaceuticals were empirical or almost random to chance. The success of the Hammett equation, however, made possible the chemical rationalization of small substructural regions, which allowed the appearance of quantitative structure activity relantionship (QSAR), during the 1960s. Since then, the reductionist search for information capable of describing biomacromolecules or more complex biological systems, has become a common activity in innumerous research centers all over the world. More recently, however, the advent of combinatorial chemistry has brought new advances to the search, mass identification and optimization of new bioactive chemical entities.

To commemorate the 25th anniversary of the Brazilian Chemical Society, a special issue of Química Nova has been dedicated to the Society (Química Nova, vol. 25, 2002), in which is written the following: According to a personal communication from Professor Toshio Fujita, the pioneer researcher Corwin Hansch visited Brazil during 1966, for the third Simpósio Internacionalde Farmacologia at Universidade de São Paulo, at which he gave a lecture. His talk was mainly concern to the well known Hansch-Fujita method. His visit to Brazil was by invitation from Professor Rocha e Silva, one of the organizers of the Brazilian part of the event.

In 1964, Professor Corwin Hansch published the first article on quantitative structure activity relantionship and, years later, Brazil entered the international scene with some historic publications by the Professors Andrejus Korolkolvas and Ivan da Rocha Pitta. Professor Andrejus Korolkovas was also the pioneer to write and translate into Portuguese his book MedicinalChemistry. Thus, a real school was formed, mainly within Faculties of Pharmacy, in which the subject of pharmacology/ pharmaceutical chemistry is taught. The production of literature in this area continues to evolve and has culminated with the publication of a new book on the present nature of medicinal chemistry, by the Professors Eliezer Barreiro and Carlos Alberto Mansour Fraga.

One of the first attempts to systematize and unveil the inherent activities of medicinal chemistry, of significant increasing effect, occurred in 1988-1989, when an exchange began between Brazilian researchers and those abroad. Initially in the QSAR area, there was the participation of several foreign researchers, but had the dynamic contribution of Professor Hugo Kubinyi.

For the first cople of years, the methodologies used in QSAR, their potentials and limitations, were divulged in different regions of Brazil, mainly through the ambit of post-graduate courses and research.

The second stage concerned the development of research projects, now carried out in collaboration with other research groups, research institutes and universities in Brazil as well as abroad. These were and have been feasible due to financing, in the great majority of cases by funding agencies with PhD, MSc and undergraduate grants. As a result of this exchange, two workshops were held at the São Paulo University, IQ/USP, on “Chemical Structure and Biological Activity”, in 1991 and 1994.

The great interest of these events may be evaluated by the elevated number of participants presenting posters (over 100, in each of them), coming from all over Brazil and South America, and their effect was significant and determinant for the following actions: creation of the Chemical Structure and Biological Activity Division (SA), at SBQ, precursor of the Medicinal Chemistry Division, formed in 1998; formation of research group (involving researchers and post-graduate students) in the QSAR/3D-QSAR area in teaching and research institutions; post-graduate programs; visits of Brazilian researchers to specialized laboratories abroad; expressive increase in the participation of Brazilian researchers in congresses abroad and their consolidation within the international scientific community.

The Division of Medicinal Chemistry of the Brazilian Chemical Society, with this knowledgement, has established as one of its tasks, the organization of THE BRAZILIAN SYMPOSIUM IN MEDICINAL CHEMISTRY, called BRAZMEDCHEM.

Many renowned Brazilian as well as foreign scientists gathered in Caxambu in the state of Minas Gerais from the 11th to the 16th of November 2001, to discuss medicinal chemistry in a country of such outstanding biodiversity. There were 125 participants, represented by 6% non-academics, 44% students and 50% academicians and 115 scientific works were presented in the following areas: Perspectives in Drug Discovery and Designof Antiprotozoal Drugs, 21; Receptor-based Prediction of BindingAffinities, 7; Applications of Multivariate QSAR, 35; MedicinalChemistry of Natural Products, 23; Synthesis and Bioassay, 18; Miscellaneous, 11. In addition, there were 17 plenary conferences and 9 oral presentations.

Consequently, Medicinal Chemistry has become a subject of an essentially collaborative character, in which the joint efforts of chemists, biologists, spectroscopists, geneticists, biotechnicians have become noteworthy. Thus, this special issue of the Journalof the Brazilian Chemical Society is dedicated to those individuals who gathered there so that a science of the importance of medicinal chemistry could be born in a country like Brazil.