Frigivelsesfaktor

Frigivelsesfaktor is a term used in Danish-language technical literature to describe the release of a substance from a system into its surroundings. In many fields it denotes the release fraction or release rate of an active ingredient from a formulation, material, or device under defined conditions.

In pharmacology and pharmaceutics, frigivelsesfaktor characterizes how much drug is released over time from dosage forms such as tablets or implants. It can be expressed as a cumulative fraction released F(t) = m(t)/M0, where m(t) is the amount released at time t and M0 is the initial amount loaded. The instantaneous release rate corresponds to dF/dt. This parameter is central to evaluating and comparing formulation performance and release mechanisms.

Applications of frigivelsesfaktor include assessing and optimizing controlled-release systems, supporting regulatory submissions, and understanding the behavior of coatings, matrices, and carriers. It is also used in related fields such as environmental protection and agriculture to quantify the release of active constituents from polymers and other delivery systems.

Measurement and modeling typically rely on in vitro dissolution or diffusion tests to generate release-versus-time data. The data are often fitted to models such as Higuchi or Korsmeyer-Peppas to interpret mechanisms (diffusion, erosion, or a combination). Factors influencing frigivelsesfaktor include matrix composition, porosity, drug loading, pH, temperature, and agitation. Limitations include condition-specific results and the imperfect translation of in vitro release to in vivo behavior.

Origin and related terms: the term derives from frigivelse (release) and faktor (factor); it is related to release kinetics and dissolution phenomena in pharmaceutics and materials science.