CGMP processes

Table 1 Components Included in CGMP Process Validations...

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When common resins and aqueous solvents were used to develop a purification process at the research bench, the purification methods can usually be scaled-up with minimal problems. However, if organic solvents have been used, scahng up to a cGMP process may be more complicated. For example, if acetonitrile is used for purification and there are no issues in the acute toxicity studies required by the FDA, then use of acetonitrile is not a problem and scale-up is straightforward. However, if toxicity is observed, it will not be clear if the observed toxicity is due to CCL21 or to acetonitrile residue. Thus, the risk/benefit of including acetonitrile in the purification process should be carefully weighed. 

Other offices within ODER may become involved in the review process via consults. Eor example, the Office of Epidemiology and Biostatistics analyzes statistical data, the Office of Research Resources provides bioavailabiHty reviews, and the Office of Compliance determines from the results of inspections whether the firms meet EDA s Current Good Manufacturing Practice (cGMP) regulations. Advisory committees composed of independent experts are often asked to meet and further analyze the data. Often they also advise as to what additional data and information may be needed. After PDA s review is completed, PDA issues either a Summary Basis of Approval (SBA) for the dmg or a recommendation against approval. If approved, PDA releases the SBA and a summary of the safety and effectiveness data to the general pubHc. 

In the preparation of classical killed or toxoid vaccines, simple process technology was used. With the advance of new vaccines, far more sophisticated process technologies are needed. The desire to reduce side effects of vaccination requires processes which will yield antigens of extreme purity. The new regulation in cGMP requires consistent production procedures, and global competition also demands that the most efficient process technology be appHed. 

The design of the system must take into account possible variation of critical control parameters that could affect performance. The maximum performance of the process should be defined by a reasonable safety margin. In order to comply with cGMP guidelines, established validation protocols, and parameters should allow the process to achieve reproducible purity and yield under stressed conditions. This implies that the industrial SMB system must be stressed to simulate worst-case conditions for process validation. 

Involved in penile erection sildenafil citrate (Viagra) affects this process by inhibiting a cGMP phosphodiesterase... 

The effect of receptor stimulation is thus to catalyze a reaction cycle. This leads to considerable amplification of the initial signal. For example, in the process of visual excitation, the photoisomerization of one rhodopsin molecule leads to the activation of approximately 500 to 1000 transdudn (Gt) molecules, each of which in turn catalyzes the hydrolysis of many hundreds of cyclic guanosine monophosphate (cGMP) molecules by phosphodiesterase. Amplification in the adenylate cyclase cascade is less but still substantial each ligand-bound P-adrenoceptor activates approximately 10 to 20 Gs molecules, each of which in turn catalyzes the production of hundreds of cyclic adenosine monophosphate (cAMP) molecules by adenylate cyclase. 

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