138 - Hidden Pharmaceutics: The Fascinating Science Behind Dosage Formulations

In this episode, we discuss the fascinating science of pharmaceutics with Dr. Kristen Ahlschwede and Dr. Rahul Deshmukh. We explore how dosage forms and excipients play an important role in how a drug product behaves in the human body with a particular focus on fentanyl patches, osmotic tablets (with laser-drilled holes), Depakote Sprinkles, and IV amiodarone.

Key Concepts

  1. Fentanyl patches were reformulated from a drug-in-a-reservoir system to an adhesive matrix system to prevent abuse and misuse. The new formulation prevents fentanyl from "leaking" out when cut.
  2. Osmotic tablet systems, such as Procardia XL, Glucotrol XL, and Concerta, use an "active" layer (containing drug) adjacent to a "push" layer that is osmotically active. When the push layer is exposed to water in the GI tract, it swells and pushes the active layer through a small laser-drilled precision hole.
  3. "Sprinkle" dosage forms typically involve small pellets inside a capsule, such as Depakote Sprinkles. The capsule itself does not delay or extend release; instead, the pellets themselves are involved in prolonging the absorption profile of the drug.
  4. Amiodarone IV is commercially available in two formulations -- the conventional formulation (Cordarone) contains benzyl alcohol and tween 80 to solubilize the drug but these excipients are associated with hypotension. A newer formulation (Nexterone) uses cyclodextrin as a solubilizing agent and is not associated with hypotension (although has a risk of nephrotoxicity, especially at higher cumulative doses).

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