Claims for Patent: 5,981,260

Summary for Patent: 5,981,260

Title:	Process for the production of cell mass and/or fermentation products under sterile conditions
Abstract:	Process for the production of cell mass and/or fermentation products under sterile conditions, during which the fermentation mixture, at least at times, is recycled and the metabolic products of the cultivated cells, and possibly the cell mass are separated; the process comprises the following steps: charging the fermentation equipment with a sufficient amount of nutrient medium to start the required cell culture. sterilizing the equipment as well as adjustment of the required concentration of nutrient medium, inoculation of the nutrient medium with the starter culture and allowing undisturbed growth of the culture for a defined time, increasing the concentration of the nutrient medium to the specific nutrient medium concentration of the cell culture by simultaneously increasing the volume of the nutrient medium to the working volume of the fermenter and increasing the concentration of cells, transition to continuous procedure with exchange of the nutrient medium and separation of the metabolic products as well as complete or partial cell recycling, termination of the continuous procedure at a required time, harvest of the cell mass under sterile conditions, and possibly repetition of some or all of the abovementioned steps in the order stated, as well as a device for the implementation of these processes.
Inventor(s):	Metz; Michael (D-7000 Stuttgart 1, DE)
Assignee:
Application Number:	07/795,899
Patent Claims:	1. Process for the production of cell mass under sterile conditions, comprising the following fermentation stages: a) a batch fermentation stage under sterile conditions comprising the steps of: 1) charging a fermentor with a sufficient amount of nutrient medium concentrate to start a cell culture; 2) sterilizing the fermentor and the nutrient medium concentrate therein and diluting the nutrient medium concentrate to a concentration sufficiently lower than a specific nutrient medium concentration to permit optimal cell multiplication and to establish adaptation of the cells to the nutrient medium; 3) inoculating the nutrient medium with cells; and 4) allowing undisturbed growth for a period of time prior to reaching conditions of substrate limitation; b) a fed-batch fermentation stage under sterile conditions comprising: adding nutrient medium to the dilute nutrient medium after said period of time to increase the concentration of the nutrient medium to said specific nutrient medium concentration to attain an exponential average growth rate of said cells, said adding of nutrient medium increasing the volume of the nutrient medium to a final volume of the fermentor to maintain said exponential average growth rate of said cells; and c) a continuous fermentation stage under sterilized conditions comprising the steps of: 1) reducing the volume of the nutrient medium in the fermentor concomitantly with at least partial cell recycling and adding sterilized nutrient medium to the fermentor; and 2) terminating the continuous fermentation stage by harvesting cells under sterile conditions after the nutrient medium is completely exhausted. 2. The process according to claim 1 wherein the amount of nutrient medium added in the continuous fermentation stage is increased proportionately to the exponential growth of the culture and is held constant when maximal cell separation is reached. 3. The process according to claim 1 wherein the nutrient medium is added under the control of a control parameter whose value is continuously determined, said control parameter being selected from the croup consisting of pH value, CO.sub.2 value and O.sub.2 concentration. 4. The process according to claim 3, wherein said pH value is determined in the fermentor and is held constant by addition of sodium hydroxide. 5. The process according to claim 4 wherein an amount of a sterilized nutrient medium is added which is equivalent to the amount of sodium hydroxide added, and which amount of nutrient medium varies in accordance with a factor k proportional to the growth rate of the cell culture during its growth phase. 6. The process according to claim 5 wherein nutrient medium becomes exhausted and is replaced according to a shell curve which is specific for the cell culture and which takes into account the cell mass present, the growth rate and the culture conditions of the cell culture. 7. The process according to claim 6 wherein the cell culture is adjusted to a required growth rate. 8. The process according to claim 1 wherein said undisturbed growth of the culture is implemented at least in part in batch mode. 9. The process according to claim 1 wherein the harvesting of the cells under sterile conditions further comprises separation of metabolites and the cells by centrifugation. 10. The process according to claim 1 wherein said diluting is carried out by injecting cold, sterile water. 11. The process according to claim 1 wherein during the harvesting of the cells under sterile conditions at least a portion of the cells is recycled. 12. The process according to claim 1 wherein said cells include aerobic cells and which process further includes the step of aerating the nutrient medium with air enriched with pure oxygen.

Details for Patent 5,981,260

Applicant	Tradename	Biologic Ingredient	Dosage Form	BLA	Approval Date	Patent No.	Expiredate
Merck Sharp & Dohme Corp.	ZOSTAVAX	zoster vaccine live	For Injection	125123	05/25/2006		2016-11-09