[Biotechnical production of drugs with special reference to tissue-type plasminogen activator]

On the basis of recombinant DNA-technology, new biotechnology is able to provide active human proteins which can be applied for replacement therapy to patients, whose symptoms of illness are based on the lack of these proteins. One of the most thoroughly investigated compounds in this aspect is tissue plasminogen activator (t-PA) which under pathophysiological conditions is not available in sufficient quantities; as a result formed thrombi cannot be dissolved sufficiently by endogenous means. Consequently, t-PA is produced biotechnically and applied exogenously to the patients. Such proteins only can be produced by biotechnology for therapeutic purposes because a chemical synthesis is not economical and isolation from human tissues or body fluids is not possible due to low concentrations, safety aspects or ethical reasons. Resulting from the knowledge of molecular biology, the genetic information for the synthesis of a distinct protein can be transferred into a suitable host cell for efficient production, by methods of recombinant DNA-technology. Thereby the choice of the producing organism is determined by the complexity of the protein. After the growth phase of the producing cells the biological active protein is obtained with a purity greater than 99.9% from the production bioreactor by protein chemical methods. Quality assurance is guaranteed by manifold protein chemical, electrophoretic, immunologic, enzymatic and biological methods. A high stability of such biologically active proteins is achieved by lyophilization after achieving a high degree of purity and a suitable formulation.(ABSTRACT TRUNCATED AT 250 WORDS)