1. US Food and Drug Administration, Center for Drug Evaluation and Research, Office of New Drug Quality Assessment. Quality by design implementation: significant accomplishments to date. www.fda.gov/aboutfda/transparency/track/ucm238167.htm.
2. ICH harmonised tripartite guideline Q8(R2): pharmaceutical development (Step 4). International conference on harmonisation of technical requirements for registration of pharmaceuticals for human use. Geneva, Switzerland, August 2009.
3. Pikal M. Freeze drying. In: Swarbrick J, editor. Encyclopedia of pharmaceutical technology, vol. 1. New York: Informa Healthcare USA, Inc; 2007. p. 1807–73.
4. Pikal MJ, Rigsbee D, Roy ML, Galreath D, Kovach KJ, Wang W, Carpenter JF, Cicerone MT. Solid state chemistry of proteins: II. The correlation of storage stability of freeze-dried human growth hormone (hGH) with structure and dynamics in the glassy solid. J Pharm Sci. 2008;97(12):5106–21.
5. Pikal MJ, Rigsbee DR. The stability of insulin in crystalline and amorphous solids: observation of greater stability for the amorphous form. Pharm Res. 1997;14:1379–87.