Semi-synthetic production

The p-lactams, mainly penicillins and cephalosporins, are by production volume the most important class of antibiotics worldwide, enjoying wide applicability towards a range of infectious bacteria. Most of the key molecules are semi-synthetic products produced by chemical modification of fermentation products. Production of these molecules has contributed significantly to the development of large-scale microbial fermentation technology, and also of large-scale biocatalytic processing. 

Drug is derived from French word drogue means a dry herb. Drugs are obtained mainly from plants, animals, microbes and mineral sources, but a majority of them that are used therapeutically are from synthetic or semi-synthetic products. 

The commercial production carried out by various companies is estimated to be ca. 2000 tyear-1 worldwide [7]. Due to the common solubility in water and various other solvents (e.g. DMSO, formamide), the biocompatibility, and the ability of degrading in certain physical environments, dextran is already successfully applied in the medical and biomedical field [8]. The physiological activity of dextran and its derivatives, indicated also by a very large number of publications in this area of research, is in contrast to inadequate structural analysis of both dextran and their semi-synthetic products. Only a few publications, in contrast to extensive studies in cellulose and starch chemistry [9,10], deal with the defined functionalisation and characterisation of dextran for adjusting desired features. 

The semi-synthetic production of vitamin C is rapidly moving to a full biotech process. Vitamin C (ascorbic acid) is an important segment in the worldwide vitamin market with a market share of approximately 20 percent. Its worldwide sales amounted to around USD 0.5 bilHon in 1999. The traditional route to vitamin C is a multistep process involving chemical and fermentative steps. It starts with the catalytic hydrogenation of D-glucose to D-sorbitol, followed by the fermentative oxidation of D-sorbitol to L-sorbose, which is then converted... 

Biological/biotechnologiccd, peptide, oligonucleotides, radiopharmaceuticals, fermentation and semi-synthetic products derived therefrom, herbal products, cmd crude products of cmimal or plant origin are not covered. 

Natural and semi-synthetic products Vinca alkaloids... 

In spite of the broad antibacterial spectrum of aminoglycosides and their effective utilisation in cases of severe bacterial diseases, world-wide attempts have been made to develop new aminoglycosides with improved properties and reduced side effects. A main goal in the development of new semi-synthetic products has been the selective protection and modification or elimination of the numerous hydroxyl-and amino groups, the exchange of specific aminosugars or aminocyclitols and the introduction of amino acids as in butirosin. 

Although recent advances in total synthesis are now approaching feasibility for structure-activity studies, chemical modification of erythromycin is still the most practical route for the synthesis of derivatives, since the starting material is readily available from fermentation sources. All of the commercially available derivatives of erythromycin as well as those in various stages of development are semi-synthetic products. The rationale for synthesis of many of these derivatives has been largely influenced by the mechanism of decomposition of erythromycin. 

It has been suggested that Taxol exerted its activity by preventing depolymerization of the microtubule skeleton. Clinical use of pachtaxel includes a lot of solid tumors with best results in ovarian and breast cancers. Extraction of paclitaxel from the yew bark was quite difficult three trees for Ig of drug (one cure of chemotherapy). This difficulty encouraged the pursuit of semi-synthetic production. 

Paddon, C.J. et al (2013) High-level semi-synthetic production of the potent antimalarial artemisinin. Nature, 496 (7446), 528 -532. 

From the above account, it is evident that the therapeutic range of the original penicillin G has been considerably extended through the new semi-synthetic products. These are, however, more costly, and should not be prescribed without good reason. An economy can be effected, when giving a member of the amoxycillin family orally, by prescribing oral probenecid 3.16) as well, because this decreases renal elimination of penicillins. 

The industrial process uses this photochemical step as well In April 2013, Sanofi announced the launch ofa semi-synthetic production facility for artemis-... 

Besides the naturally occurring cationic PS chitin and chitosan, a huge variety of semi-synthetic products is available, which are based on anchoring cationic groups onto the polysaccharide backbone. Examples include cationic starch and cationic cellulose derivatives, which are widely used for industrial purposes (cationic starch in paper ) and also in medical applications (cationic cellulose as additives, e.g. JR-400 and Quatrisoft LM-200 in hygienic products). However, applications in regenerative medicine are rather poorly developed for these materials and therefore a discussion is excluded at this point. 

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