Example of Create Stability Study Worksheet

A quality engineer for a pharmaceutical company wants to determine the shelf life for pills that contain a new drug. The concentration of the drug in the pills decreases over time. The engineer wants to determine when the pills get to 90% of the intended concentration. Because this is a new drug, the company has only 5 pilot batches to use to estimate the shelf life. The engineer tests one pill from each batch at nine different times.

To organize the data for analysis, the engineer creates a data collection worksheet for the study.

  1. Choose Stat > Regression > Stability Study > Create Stability Study Worksheet.
  2. Select Test times in numeric format, at varying intervals.
  3. In Number of test times, enter 9.
  4. In Number of batches, enter 5.
  5. Click OK.

Interpret the results

The study includes 9 test times and 5 batches for a total of 45 runs. The engineer records the response data in Minitab. Then, the engineer uses Stat > Regression > Stability Study > Stability Study to analyze the data and determine the shelf life for the pills.

Note

Minitab randomizes the batches by default. If you replicate the example, your run order will be different.

Stability Worksheet

Summary Testing times: 9 Batches: 5 Samples per batch at each time: 1 Total runs: 45
C1 C2 C3-T C4
RunOrder Month Batch Response
1 0 1 *
2 0 2 *
3 0 5 *
4 0 3 *
5 0 4 *
6 3 4 *
7 3 1 *
8 3 2 *
9 3 3 *
10 3 5 *
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