The fraction of drug absorbed using the Wagner–Nelson method may be used to distinguish between the first-order drug absorption rate of a conventional (immediate-release) dosage form (A) and an extended-release dosage form (C). Curve B represents an extended-release dosage form with zero-order absorption rate. Source: Chapter 17. Modified-Release Drug Products, Applied Biopharmaceutics & Pharmacokinetics, 6e Citation: Shargel L, Wu-Pong S, Yu AC. Applied Biopharmaceutics & Pharmacokinetics, 6e; 2012 Available at: https://accesspharmacy.mhmedical.com/DownloadImage.aspx?image=/data/books/shar6/shar6_c017f013.png&sec=41492022&BookID=513&ChapterSecID=41488035&imagename= Accessed: November 04, 2017 Copyright © 2017 McGraw-Hill Education. All rights reserved