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A Horse of a Different Color: How Formulation Influences Medication Effects

  • Meghan M. Grady (a1) and Stephen M. Stahl (a1) (a2) (a3)


A medication's pharmacokinetic properties can be as important as its efficacy in determining how successful a treatment is. Formulation plays a critical role in absorption, distribution, and elimination of a drug, which in turn can influence the clinical profile of a medication, including onset and duration of action, consistency of plasma levels, ability to cross the blood-brain barrier, and other factors. Advances in drug delivery technology mean that formulation is now an integral component in the development of a drug. Likewise, formulation is one of the factors that may influence selection of a medication to suit the needs of a particular patient. This article briefly reviews the technologies commonly applied in the development of psychotropic medications, with emphasis on the various oral modified-release formulations, and discusses how formulation can be used to optimize the efficacy and tolerability of psychotropic drugs.


Corresponding author

*Address for correspondence: Meghan M. Grady, BA, Director, Content Development, Neuroscience Education Institute, Phone: 760-931-8857, ext. 109 (Email


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Stephen M. Stahl, MD, PhD, Adjunct Professor of Psychiatry at the University of California San Diego, Honorary Visiting Senior Fellow at the University of Cambridge, Chairman of the Neuroscience Education Institute (NEI).

Acknowledgment of Financial Support: The activity is supported by an educational grant from Valeant Pharmaceuticals International, Inc.



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1.Stahl, SM, Wets, KM. Recent advances in drug delivery technology for neurology. Clin Neuropharmacol. 1988; 11(1): 117.
2.Stahl, SM. At long last, long-lasting psychiatric medications: an overview of controlled-release technologies. J Clin Psychiatry. 2003; 64(4): 355356.
3.Chen, ML, Shah, VP, Ganes, D, et al. . Challenges and opportunities in establishing scientific and regulatory standards for assuring therapeutic equivalence of modified-release products: workshop summary report. Eur J Pharmaceutical Sci. 2010; 40: 148153.
4.Brannon-Peppas, L. Preparation and characterization of crosslinked hydrophilic networks. In: Absorbent polymer technology. Amsterdam: Elsevier; 1990. pp. 4566.
5.Colombo, P, Bettini, R, Santi, P, Peppas, NA. Swellable matrices for controlled drug delivery: gel-layer behavior, mechanisms and optimal performance. Pharm Sci Technolo Today. 2000; 3(6): 198204.
6.Wen, H, Park, K. Oral controlled release formulation design and drug delivery: theory to practice, Hoboken, New Jersey: John Wiley & Sons, Inc.; 2010.
7.Tiwari, SB, Rajabi-Siahboomi, AR. Extended-release oral drug delivery: technologies: monolithic matrix systems. Methods Mol Biol. 2008; 437: 217243.
8.Frutos, P, Pabon, C, Lastres, JL, Frutos, G. In vitro release of metoclopramide from hydrophobic matrix tablets. Influence of hydrodynamic conditions on kinetic release parameters. Chem Pharm Bull. 2001; 49(10): 12671271.
9.Roy, P, Shahiwala, A. Multiparticulate formulation approach to pulsatile drug delivery: current perspectives. J Controlled Release. 2009; 134: 7480.
10.Siepmann, F, Hoffman, A, Leclercq, B, Carlin, B, Siepmann, J. How to adjust desired drug release patterns from ethylcellulose-coated dosage forms. J Controlled Release. 2007; 119: 182189.
11.Felton, LA. Characterization of coating systems. AAPS PharmSciTech. 2007; 8(4): E1E9.
12.Ball, AM, Smith, KM. Optimizing transdermal drug therapy. Am J Health Syst Pharm. 2008; 65(14): 13371346.
13.Keith, S. Advances in psychotropic formulations. Prog Neuro-psychopharmacol Biol Psychiatry. 2006; 30: 9961008.
14.Muramatsu, RS, Litzinger, MHJ, Fisher, E, Takeshita, J. Alternative formulations, delivery methods, and administration options for psychotropic medications in elderly patients with behavioral and psychological symptoms of dementia. Am J Geriatr Pharmacother. 2010; 8(2): 98114.
16.U.S. Food and Drug Administration Center for Drug Evaluation and Research. Approved drug products with therapeutic equivalence evaluations. 31st ed.; 2011.
17.Sankar, R, Glauser, TA. Understanding therapeutic equivalence in epilepsy. CNS Spectr. 2010; 15(2): 112123.
18.Wilner, AN. Therapeutic equivalency of generic antiepileptic drugs: results of a survey. Epilepsy Behav. 2004; 5: 995998.
19.Gilman, JT, et al. . Carbamazepine toxicity resulting from generic substitution. Neurology. 1993; 43: 26962697.
20.Chenu, F, et al. . Comparison of pharmacokinetic profiles of brand-name and generic formulations of citalopram and venlafaxine: a crossover study. J Clin Psychiatry. 2009; 70(7): 958966.
21.U.S. Food and Drug Administration. Accessed October 31, 2011.
22.Desmarais, JE, Beauclair, L, Marolese, HC. Switching from brand-name to generic psychotropic medications: a literature review. CNS Neurosci Ther. 2010; Epub ahead of print.
23.Endrenyi, L, Tothfalusi, L. Do regulatory bioequivalence requirements adequately reflect the therapeutic equivalence of modified-release drug products? J Pharm Pharmaceut Sci. 2010; 13(1): 107113.
24.Raw, AS, Lionberger, R, Yu, LX. Pharmaceutical equivalence by design for generic drugs: modified-release products. Pharm Res. 2011; 28: 14451453.


A Horse of a Different Color: How Formulation Influences Medication Effects

  • Meghan M. Grady (a1) and Stephen M. Stahl (a1) (a2) (a3)


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