Working cell bank

Biotechnology feniientation/ cell culture Establishment of master cell bank and working cell bank Maintenance of working cell bank Cell culture and/or fermentation Isolation and purification Physical processing, and packaging... 

Possible contamination by chemical or biological substances is one of the most important concerns when producing pharmaceutical proteins. Plant cell cultures ensure the production of the desired protein in a controlled, sterile and sealed environment and can be adapted to cGMP conditions. Therefore, the risk of contamination is minimized and the production conditions can be modified more easily in a contained reactor than in the field. Another advantage is the ability to freeze plant suspension cells in liquid nitrogen [66, 67] so that master and working cell banks can be established, a prerequisite for cGMP procedures [68]. 

Upstream processing is deemed to commence when a single vial of the working cell bank system (see later) is taken from storage and the cells therein cultured in order to initiate the biosynthesis of a batch of product. The production process is deemed complete only when the final product is filled in its final containers and those containers have been labelled and placed in their final product packaging. 

The cell bank s construction design is normally two tiered, consisting of a master cell bank and a working cell bank (Figure 5.6). The master cell bank is constructed first, directly from a culture of the newly constructed production cell line. It can consist of several hundred individually stored ampoules. 

Figure 5.6 The master cell bank/working cell bank system. For simplicity, each bank shown above contains only five ampoules. In reality, each bank would likely consist of several hundred ampoules. Working cell bank number 2 will be generated from master cell bank vial number 2 only when working cell bank number 1 is...

The upstream processing element of the manufacture of a batch of biopharmaceutical product begins with the removal of a single ampoule of the working cell bank. This vial is used to inoculate a small volume of sterile media, with subsequent incubation under appropriate conditions. This describes the growth of laboratory-scale starter cultures of the producer cell line. This starter culture is, in turn, used to inoculate a production-scale starter culture that is used to inoculate the production-scale bioreactor (Figure 5.7). The media composition and fermentation conditions required to... 

Figure 5.7 Outline of the upstream processing stages involved in the production of a single batch of product. Initially, the contents of a single ampoule of the working cell bank (a) are used to inoculate a few hundred millilitres of media (b). After growth, this laboratory-scale starter culture is used to inoculate several litres/tens of litres of media present in a small bioreactor (c). This production-scale starter culture is used to inoculate the production-scale bioreactor (d), which often contains several thousands/tens of thousands litres of media. This process is equally applicable to prokaryotic or eukaryotic-based producer cell lines, although the bioreactor design, conditions of growth, etc., will differ in these two instances...

Master Cell Bank and Working Cell Bank Origin... 

The need to transport temperature-sensitive raw materials and products, such as cell line, medium, large molecule drugs, and vaccines, means that some form of control during transportation is needed. For example, a working cell bank for the production of proteins may be transported in liquid nitrogen (-196 °C) and that of protein and vaccines in dry ice (-78 °C) in order to protect the integrity of the materials. Data loggers are used to record the temperature... 

The upstream processing element of the manufacture of a batch of biopharmaceutical product begins with the removal of a single ampoule of the working cell bank. This vial is used to inoculate a small volume of sterile growth medium, with subsequent incubation under... 

Production is based on a validated seed-lot system using a host-vector combination that has been shown to be suitable to the satisfaction of the competent authority. The seed-lot system uses a master cell bank and a working cell bank derived from the master seed lot of the host-vector combination. A detailed description of cultivation, extraction and purification steps and a definition of the production batch shall be established. 

The working cell bank is a homogeneous suspension of the cell material derived from the master cell bank(s) at a finite passage level, distributed in equal volumes into individual containers for storage (e.g. in liquid nitrogen). 

All containers of master or working cell banks and seed lots should be treated identically during storage. Once removed from storage, the containers should not be returned to the stock. 

A master or working cell bank is poorly characterized. 

For vaccines the starting material problem was addressed early, and methods were developed to control the identity and purity of the starting material. These studies often were completed with the aid of, and in the laboratories of, scientists at CBER with the conditions mutually agreed upon at the time of approval. Specifically, the development of master cell bank (MCB) and manufacturers working cell bank (MWCB) concepts helped... 

CMC information It should contain sufficient detail to assure identification, quality, purity, and strength of the investigational drug. It should include stability data of duration appropriate to the length of the proposed study. FDA concerns to be addressed focus on products made with unknown or impure components, products with chemical structures known to be of likely high toxicity, products known to be chemically unstable, and products with an impurity profile indicative of a health hazard or insufficiently defined to assess potential health hazard, or poorly characterized master or working cell bank. 

Preparation and characterization of the clone master cell bank and working cell bank... 

To guarantee the availability of cells and the maintenance of their characteristics, a sufficiently large quantity of cells is kept in master and working cell banks, as discussed in Chapters 13 and 14. The number of cryotubes containing cells in a working cell bank is calculated to ensure that, for the whole expected lifespan of a product, each production lot will be obtained starting with cells from identical cryotubes. The most widely employed method for the conservation of cell banks is cryoconservation in liquid nitrogen at -196°C, which avoids mutations that could potentially alter cell characteristics. 

Once the cell line is selected as a host for production, a cell bank system must be generated to guarantee the availability of an adequate source of equivalent cells to use through the product s lifetime in the market. Usually, the cell bank system consists of two levels a master cell bank (MCB) and a manufacturer s working cell bank (WCB). 

LSBL MAP MCB NDA NIH PPC PTC QA QC RAP WCB WCP WHO large-scale biosafety level mouse antibody production master cell bank new drug application National Institutes of Health post-production cells points to consider quality assurance quality control rat antibody production working cell bank well-characterized product World Health Organization... 

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