It has been said that formulation is as much science as it is an art. It involves understanding the ingredients and making
justifiable selections and adjustments based on the knowledge of the special characteristics of the ingredients and working
hard to get the most out of the excipients in the holistic sense. In the end, success stories can be told in many aspects
of the drug products from the robust formulation and manufacturing process, to smooth scale up and process validation, to
strong regulatory acceptance and market-share domination in their therapeutic areas. Paying attention to pharmaceutical excipients
and their regulatory issues is an indispensable initial step to the success of drug products.
Dorothy Chang, MD,* is a resident doctor at Thomas Jefferson University Hospital, 833 Chestnut St., Suite 220, Philadelphia, PA 19107. Rong-Kun Chang, PhD, is associate director at Supernus Pharmaceuticals (Rockville, MD).
*To whom all correspondence should be addressed.
Submitted: Jan. 15, 2007. Accepted: March 9 2007.
Keywords: Excipients, Formulation, USP
1. M. Ash and I. Ash, Handbook of Pharmaceutical Additives (Gower Publishing Limited, Hampshire, England, 1995).
2. Handbook of Pharmaceutical Excipients, R. Rowe, P.J. Sheskey, and P. J. Weller, Eds. (Pharmaceutical Press and American Pharmaceutical Association, Chicago, IL,
3. International Pharmaceutical Excipients Council-Americas, "What are Pharmaceutical Excipients?"
4. Center for Drug Evaluation and Research (CDER), "Inactive Ingredient Search for Approved Drug Products,"
5. CDER, Quality Systems Approach to Pharmaceutical Good Manufacturing Practices, Draft Guidance (Rockville, MD, 2004).
6. S.U. Ahmed, V.Naini, and S.R. Vaithiyalingam, "Physicochemical Characteristics of Drugs and Excipients: An Overview,"
Amer. Pharm. Rev. 9 (3), 47 –52 (2006).
7. J.R. Johanson, "Defining the Physical Functionality of Excipients, Bulk Drugs and Formulations," Innovations in Pharmaceutical Technology 1 (2), 136–146 (1999).
8. D. Bugay and W.P. Findlay, Pharmaceutical Excipients: Characterization by IR, Raman, and NMR Spectroscopy (Marcel Dekker, Inc., New York, NY, 1999).
9. B.D. Rege et al., "Effect of Common Excipients on Caco-2 Transport of Low-Permeability Drugs," J. Pharm. Sci. 90 (11), 1776–1786 (2001).
10. P.D. Ward, T.K. Tippin, and D.R. Thakker, "Enhancing Paracellular Permeability by Modulating Epithelial Tight Junctions,"
PSST 3, (10), 348–358 (2000).
11. R. Chang and P. Bhatt, "Recent Trends in Oral Drug Delivery," AAPS Newsmagazine, 18–21 (March 2005).
12. "Excipient Development for Pharmaceutical, Biotechnology, and Drug Delivery Systems," A. Katdare and M. Chaubal, Eds.
(Informa Healthcare USA, New York, NY, July 2006).
13. J.M. Smith and T.R. Dodd, "Adverse Reactions to Pharmaceutical Excipients," Adv. Drug React. Ac. Pois. Rev. 1, 93–142 (1982).
14. Excipient Toxicity and Safety, W. Kotkoski, M. Weiner, L. Kotkoskie, Eds. (Marcel Dekker, New York, NY, 1999).
15. K. Jackson, D. Young, and S. Pant, "Drug–Excipient Interactions and Their Affect on Absorption," PSTT 3 (10), 338–345 (2000).