Dissolution testing determines the speed with which an active pharmaceutical ingredient(s) (APIs) is released and solubilized from a formulated matrix. This process is a critical precursor to drug uptake into the bloodstream and dissolution testing in accordance with pharmacopeial specifications is routine for oral solid dosage (OSD) forms. However, in vivo the API must also transit biological membranes within the gastrointestinal (GI) tract to enter the bloodstream.

Absorption of the API, just like dissolution, plays a critical role in determining bioavailability but is typically subject to less in vitro investigation during formulation development. This can be problematic when it comes to predicting the in vivo behavior of certain drugs. Flux measurements allow pharmaceutical formulators to navigate these issues.

The flux of an API is essentially the transit rate of molecules from donor (formulated drug) to acceptor (bloodstream) and jointly accounts for dissolution rate, solubility, and permeability – providing a wealth of valuable information.

Pion has pioneered the use of flux measurements and their application in Absorption Driven Drug Formulation (ADDF), a relatively new concept based on using flux measurements to ensure that a drug product delivers the target absorption rate.

In our latest whitepaper we take a look at case study data demonstrating the utility of flux measurements for excipients screening, to rank alternative formulation, to predict the likely outcome of in vivo PK (pharmacokinetic) trials and to assess the impact of fed state on drug absorption.