Concept of process capability indices as a tool for process performance measures and its pharmaceutical application
The main objective of the present study is to present the concept of process capability and to focus its significance in pharmaceutical industries. From a practical view point, the control charts (such as X and R hart) sometimes are not convenient summary statistics when hundreds of characteristics in a plant or supply base are considered. In many situations, capability indices can be used to relate the process parameters. The resulting indices are unit less and provide a common, easily understood language for quantifying the performance of a process. Process capability indices (PCIs) are powerful means of studying the process ability for manufacturing a product that meets specifications. Several capability indices including Cp, Cpu, Cpl and Cpk have been widely used in manufacturing industry to provide common quantitative measures on process potential and performance. The formulas for these indices are easily understood and can be directly implemented. A process capability analysis compares the distribution of output from an in-control process to its speciﬁcations limits to determine the consistency with which the specifications can be met. The process capability is also having a significant role in pharmaceutical industry. Process capability indices can be a powerful tool by which to ensure drug product quality and process robustness. Determining process capability provides far more insight into any pharmaceutical process performance than simply computing the percentage of batches that pass or fail each year.
Keywords: Process capability; Cp/Cpk; Pp/Ppk; Pharmaceutical quality, process robustness, specification
2. Jabnoun N, “Control processes for total quality management and quality assurance” Work Study; 51(4):182–190.
3. Sindhe JS, Katikar RS, “Importance of process capability and process performance indices in machine tool” International Journal of Research in Engineering & Applied Sciences, 2012; 2(2):1211-1217.
4. Czarski A, Matusiewicz P, “Influence of measurement system quality on the evaluation of process capability indices “Metallurgy and Foundry Engineering, 2012; 38(1):25-32.
5. PharmOut white paper: Process Capability: Pharm Out. 2017. Available at: https://www.pharmout.net/downloads/white-paper-process-capability.pdf. Accessed on Aug 1, 2020.
6. Chaudhry SS, Higbie JR “Practical implementation of statistical process control in a chemical industry” Pharmaceutical Research, 1989; 6(5).
7. Yu YL, “Pharmaceutical Quality by Design: Product and Process Development Understanding, and Control” Pharmaceutical Research, 2008; 25(4):781-791.
8. Statistical quality control hand book. 6 th ed. USA: Western electric Co. Inc.; 1982. P. 3-5.
9. Chen KS, Huang ML, Li RK, “Process capability analysis of an entire product” International Journal of Production Research, 2001; 39(17):4077-4087.
10. Kiran DR.Total Quality Management: Key Concepts and Case Studies. 2017. BSP Books Pvt. Ltd. Published by Elsevier Inc.; 2017.P.257-259.
11. Scott R, Process capability-The basics: part I. USA: Process central. 2020. Available at: http://processnews.blogspot.com/2020/05/process-capability-the-basics-part-1.html. Accessed on Aug 1, 2020.
12. Process Capability and Product Design.2019. Available at: https://www.npd-solutions.com/proccap.html. Accessed on Aug 1, 2020.
13. Minitab blog: Process Capability statistics: Cpk and Ppk, Working Together.2013. Available at: https://blog.minitab.com/blog/statistics-and-quality-improvement/process-capability-statistics-cp-and-cpk-working-together. Accessed on Aug 6, 2020.
14. Sall J, Lehmann A, Stephens M, Loring S. JMP start statistics- A Guide to Statistics and Data Analysis using JMP. 6 th edition.USA: Cary, NC: SAS Institute Inc: 2017.P.564-567.
15. Chen KS, Huang ML, Hung YH, “Process capability analysis with the application of Cpm” International Journal of Production Research, 2008; 46(16):4483-4499.
16. Six sigma-materials: Process Capability indices.2020. Available at: https://www.six-sigma-material.com/Process-Capability-Indices.html. Accessed on Aug 6, 2020.
17. Kane EV, “Process Capability Indices” Journal of Quality Technology, 1986; 18(1):41-52.
18. Kapadia M, Measuring your Process Capability. India: Symphony Technologies. Available at:http://www.symphonytech.com/articles/pdfs/processcapability.pdf. Accessed on Aug 1, 2020.
19. Jeang A, “Optimal process capability analysis for process design” International Journal of Production Research, 2008; 1-33.
20. Minitab blog: Process Capability statistics: Cpk vs Ppk.2016. Available at: https://blog.minitab.com/blog/process-capability-statistics-cpk-vs-ppk. Accessed on Aug 6, 2020.
21. JMP user community discussions: Short term (Cpk) and Long term (Ppk) capability in JMP.2019. Available at: https://community.jmp.com/t5/Discussions/Short-Term-Cpk-and-Long-Term-Ppk-Capability-in-JMP/td-p/218668. Accessed on Aug 10, 2020.
22. Wooluru Y, Swamy DR, Nagesh P “ The process capability analysis- A tool for process performance measures and metrics- A case study” International Journal of Quality Research, 2014; 8(3):399-416.
23. Hessing T, Process Capability (Cp and Cpk): Six sigma study guide articles.2014. Available at: https://sixsigmastudyguide.com/process-capability-cp-cpk.Accessed on Aug 6, 2020.
24. Steiner S, Abraham B, MacKay J,“ Understanding process capability indices” International Conference on Production Research, Department of statistics and Actuarial Science, University of Waterloo.
25. Bissel AF, “How Reliable Is Your Capability Index?”, Journal of Applied Statistics , 1990; 39:331-340.
26. Mcneese B, Cpk Vs. Ppk: Who Wins?: SPC for excel. 2014. Available at: https://www.spcforexcel.com/knowledge/process-capability/cpk-vs-ppk-who-wins. Accessed on Aug 1, 2020.
27. Gabriele A, Stefano N, “A Review of the Fundamentals on Process Capability, Process Performance, and Process Sigma, and an Introduction to Process Sigma Split”, International Journal of Applied Engineering Research, 2017; 12(14):4556-4570.
28. Ullman DG. “Robust decision making for engineering Design”, J. of Engineering Design, 2001; 19(1):3-13.
29. Gebresenbet T, Jain PK, Jain SC, “Preliminary manufacturability analysis using feature-function resource considerations for cylindrical machined parts”, Int. J. Computer Integrated Manufacturing, 2002; 15:361-378.
30. Bargellis A, “Design for process capability and capacity at the product conception stage” International Conference on Production Research, Department of Manufacturing Technologies, Kaunas University of Technology.
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.
Authors who publish with this journal agree to the following terms:
- Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0). that allows others to share the work with an acknowledgment of the work's authorship and initial publication in this journal.
- Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgment of its initial publication in this journal.
- Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).