Extemporaneous Preparation Instruction

Stock preparations are performed according to a standardised preparation instruction, an instruction that has been validated prior to use. This is called a Batch Preparation Instruction (BPI). Also for extemporaneous preparations, a standardised preparation instmction - a BPI - is preferred. However, often the operator has to follow a non-standardised preparation instmction that is less extensive, where no prior validations have been performed, see further Sect. 33.5. 

But sometimes an extemporaneous preparation is required where no standard formula and hence no BPI is available. In that case the preparation instruction has to be designed just before preparation can start. 

For drafting a preparation instruction for a non-standardised formulation, two routes can be followed, see Fig. 33.4. If a BPI is available for a closely related preparation, it may be possible to prepare the non-standardised extemporaneous preparation on this basis. The BPI can be changed for another strength, for example, be modified with respect to a particular excipient, or by a minor change in the applied preparation process. The changes will inevitably turn the standardised preparation instruction into a non-standardised instruction, but working in this way has... 

Fig. 33.5 Example of a pireparation instruction for non-standaidised extemporaneous preparations, fiont (a) and backside (b). The numbers correspond with the explanatirais in Sect. 33.4.2...

For products that are prepared extemporaneously at a regular basis or even for a limited stock, a product specific documentation (product file) is needed. This will include specifications, instructions, and records but also a pharmaceutical assessment of safety data, toxicity, biopharmaceutical aspects, stability, and product design. The product file should also include a product review as soon as a product is used repeatedly or over longer periods. 

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