As a growing number of nanotherapeutics enters the market, improved analytical techniques for measuring the drug release are required. Biorelevant release tests have become a standard in the prediction of in vivo pharmacokinetics but also in quality control of novel dosage forms. In the present study, two methods for testing the drug release from nanocarriers, namely the filtration technique and the dispersion releaser technology, have been investigated. Initially, the in vitro release rates were determined using two different biorelevant media. Additionally, the effect of each method on a simulated in vivo pharmacokinetic profile was studied using advanced PBPK modelling. The two methods resulted in slightly different release profiles. Applying the filtration method, an early plateau of 91.0 ± 5.3% was reached at the first sampling time point. In comparison, the release rate steadily increased to a maximum of 100.9 ± 4.1% when the dispersion releaser technology was used. Sensitivity analysis revealed how these differences translated into the PBPK-based simulation. A change in the total dissolution rate of 10% resulted in cmax values of +1.6% and −11.0%, respectively, when using input data obtained with the dispersion releaser. Data obtained by filtration translated into cmax values of ±1.8%.