John S. McConnell & Brian K. Nunnally 
Six Sigma in the Pharmaceutical Industry [PDF ebook] 
Understanding, Reducing, and Controlling Variation in Pharmaceuticals and Biologics

Six Sigma in the Pharmaceutical Industry is the first book to introduce the fundamentals of Six Sigma, examine control chart theory and practice, and explain the concept of variation management and reduction applied specifically to the pharmaceutical industry. The first half lays out a conceptual framework for understanding variation, while the second half introduces control chart theory and practice. Using case studies and statistics, the book illustrates the concepts and explains their application to actual workplace improvements. Providing the basis for a complete operating philosophy, this book focuses on core concepts and their implementation to improve the existing products and processes in the pharmaceutical industry.