This stems from the high stereo and regioselectivity inherent in the use of biocatalysts (biological systems such as whole cells (fungi, yeasts, bacteria) or isolated enzymes, which are able to discriminate a specific and selective way only one of the possible isomers of a racemic mixture, achieving the desired product form enantiopura.
This factor is vital in the pharmaceutical industry, because in most cases the compound has the desired therapeutic activity (eutómero) has a specific spatial configuration, and administration of any other isomer (distómero) can have fatal consequences (we need only cite the sad case of thalidomide). The different pharmacological activity of the two optical isomers caused the European Medicines Agency and the U.S. FDA, since 1992 only accepted as the drug eutomero, imposing severe restrictions in the case of racemic mixtures. It should be noted here that the ten top-selling drugs in Spain, seven are optically active compounds, among which we quote to enalapril, paroxetine, atorvastatin, dudesamina, fluoxetine, salmeterol, and diltiazem. In obtaining these drugs have been used in a biotransformation step. Therefore, these capacities of the biocatalysts, which can be even better engineered from the reaction, making them essential tools in the synthesis of drugs.
Moreover, the use of these biocatalysts has other advantages in regard to environmental parameters. Indeed, the use of enzymes in vitro offers an alternative to the chemical process under conditions more sustainable and less polluting. The enzymes consume less water, less products and less energy than starting the same process catalyzed by conventional catalysts, so that the environmental impact is less pure products obtained cheaply. The highly specific nature of enzymes means that biological processes not only require fewer chemical inputs, but also produce less waste streams and more manageable. To illustrate the above can serve as an example to obtain 6-aminopenicillanic acid, known as 6-APA, and used as an intermediate in the synthesis of a variety of antibiotics. The synthesis of 1 kg of 6-APA using a conventional chemical process involves the use of 0.6 kg of chloride of trimethyl silane, 1.2 kg of phosphorus pentachloride, 1.6 kg of dimetilfenilamina, 0.2 kg of ammonia, 8, 4 L of n-butanol and 8.4 L of dichloromethane while the same kg of 6-APA can be obtained by biotechnological processes from 0.09 kg of ammonia and 2 quarts of water.
The boom in biotechnology has been accompanied by the fact that pharmaceutical companies are finding it increasingly difficult to develop and market new products. The number of drugs approved each year has decreased since 1996, while R & D expenditures have increased enormously. This is one of the basic reasons why the pharmaceutical companies seeking alliances with biotechnology companies. This lack of new drugs has led the pharmaceutical industry has been accused of making too many copies of existing drugs, which only added slight clinical benefits. As a result many pharmaceutical companies are turning their attention to smaller companies in the biotechnology sector as a source of constant innovation in developing new drugs.
From all the above can be concluded that the application of biocatalysis has crossed the border to find a broad academic scope in the pharmaceutical industry, although their contribution represents only part of the production of pharmaceuticals by biotechnological methods.