Some of the factors affecting drug absorption are surface area, rate of dissolution, blood flow, lipid solubility, and pH partitioning.
Surface area relates to absorption, i.e., larger surface area relates to faster absorption. For example, stomach has relatively small surface area, but small intestine has extremely large surface area due to lining of microvilli, showing ability for better absorption of orally administered drug by intestinal surface.
Rate of dissolution relates to onset and helps determine rate of absorption. Therefore, faster dissolution relates to faster onset, and vice versa. Nevertheless, dissolution is essential for absorption.
Blood flow – simply – increased blood flow to a site, more rapid absorption of drug from that site.
Lipid solubility relates to absorption showing that highly lipid-soluble drugs show better absorption.
pH partitioning relates to difference between pH of plasma and pH at administration site that affects the tendency of the drug to be ionized in plasma.
Zusammenfassung in deutscher Sprache (Summary in German language)
Die Arzneimittelabsorption wird normalerweise durch fünf Faktoren beeinflusst, einschließlich Oberfläche, Auflösungsrate, Blutfluss, Lipidlöslichkeit und pH-Verteilung.
Burchum, J., Rosenthal, L., & Yeager, J. J. (2018). Study Guide for Lehne’s Pharmacology for Nursing Care *- eBook. Elsevier Health Sciences.
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