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Ajit NarangAjit Narang, Ph.D., works for the Drug Product Science & Technology Department of Bristol-Myers Squibb Co. in New Brunswick, N.J. on oral solid dosage forms after receiving his doctorate from the University of Tennessee, Memphis.

Although the excipients in a dosage form are inactive ingredients, they may not be pharmacologically inert. Excipients impact drug product bioavailability, stability, and manufacturability. A previous post discussed the impact of excipients on oral drug bioavailability. Oral drug bioavailability and inter-individual variability in drug absorption can sometimes result from the effect of excipients on the drug substance in the dosage form, such as salt disproportionation, binding, and microenvironmental pH. The excipients can impact drug release, solubilization, adsorption, form conversion/stabilization, complexation, microenvironmental pH modulation, gastro-intestinal motility, or gastro-intestinal physiology (e.g., metabolizing enzymes or efflux transporters).

The effect of excipient interactions on drug bioavailability are sought to be minimized in preclinical drug development to avoid any interference in the assessment of exposure and activity of the new drug candidate. For clinical and commercial drug product development, the impact of excipients is sought to be well understood and minimized or controlled. An upcoming AAPS webinar on February 27th will discuss strategies and examples to understand the impact of excipients on oral drug bioavailability with specific focus on the following three questions:

  1. How does drug self-association/micellization impact oral drug absorption and its modeling?
  2. When does drug excipient binding impact oral drug absorption? How can these be assessed experimentally?
  3. What could be the mechanistic reasons for variability in oral drug absorption, and how could these be investigated experimentally? What value do these studies add to the drug development process and decisions?

Using recently published literature on each of these topics, this webinar will highlight emerging trends in the understanding of how excipients affect the biological performance of drug products. In addition to discussing the mechanistic basis, the webinar will highlight control strategies and quality by design aspects of pharmaceutical development that can be proactively addressed during new drug development.