Are you looking to develop a capacity plan model for a pharmaceutical testing lab? Here are some things to consider using a pharmaceutical QA / QC laboratory supporting a manufacturing facility as an example.
First, consider your minimum testing load based on manufacturing forecasts. Each batch of drug product will require a minimum number of tests before, during, and after manufacturing including:
- Testing of raw materials used in the process
- Testing to ensure process equipment is clean
- In-process testing to ensure process is performing within specifications
- Final product testing for release to market
- Product stability testing (as required for some batches)
For each one of those areas you would need to model the number of samples required, the time it takes to analyze the samples, and the time it takes to get the results approved. The time it takes to get the results approved can be rate-limiting, so do not ignore it.
Now, if every process performed perfectly every time, that's basically all you would need. But they will not run perfectly; there will be problems ranging from simple analyst errors to unexplainable out-of-specification (OOS) results.
Errors and OOS results require formal documented investigations that can be quite time-consuming. Some products are more problematic than others and have more associated investigations. So you want to understand the history of each product and plan for the resources and time required for investigations in your model.
Next, pharmaceutical manufacturing processes need to be validated. Process validation is "establishing, through documented evidence, a high degree of assurance that a specific process will consistently produce a product that meets its predetermined specifications and quality characteristics." Any new processes will have to be validated and established processes are normally revalidated periodically as specified in the facility's "Master Validation Plan." Process validations often require enormous amounts of analytical resources to handle the validation sample load, and these resources compete with routine testing, so you will want to plan for validations in your model.
Finally, you should consider the introduction of new or changed processes and new products to the plant. These are also huge consumers of analytical resources as they include activities such as analytical method development, method transfer, and method validation in addition to the support and testing of "scale-up," demonstration, and validation batches. These batches also will have long-term and accelerated stability samples associated with them. Also, since they are new processes, they will generally have more investigations associated with them.
Remember, a pharmaceutical process produces two products: the drug product and the paperwork documenting the manufacturing and testing. A manufactured batch of drug product without the proper paperwork is worthless because it can not be released to the market. I want to emphasize that the preparation and approval of the documentation can be very time-consuming, so it is critical that you map these processes and include them in your model.