Abstract
Intramuscular (IM) injections deliver a plethora of drugs. The majority of IM-related literature detail s dissolution and/or pharmacokinetic (PK) studies, using methods with limited assessments of post-injection events that can impact drug fate, and absorption parameters. Food and Drug Association guidelines no longer require preclinical in vivo modeling in the U.S.A. Preclinical animal models fail to correlate with clinical outcomes, highlighting the need to study, and understand, IM drug fate in vitro using bespoke models emulating human IM sites. Post-IM injection events, i.e. underlying processes that influence PK outcomes, remain unacknowledged, complicating application of in vitro methods in preclinical drug development. Understanding such events could guide approaches to predict and modulate IM drug fate in humans. This article reviews challenges in biorelevant IM site modeling (i.e. modeling drug fate outcomes), the value of technologies available for developing IM injectables, methods for studying drug fate, and technologies for training in performing IM administrations. PubMed, Web-of-Science, and Lens databases provided papers published between 2014 and 2024. IM drug research is expanding what injectable therapeutics can achieve. However, post-injection events that influence PK outcomes remain poorly understood. Until addressed, advances in IM drug development will not realize their full potential.

This publication has 149 references indexed in Scilit: