Determining drug loading and release kinetics in nanoparticles

• Source: [[ @gioria2018 Are existing standard methods suitable for the evaluation of nanomedicines: some case studies ]]
• Tags: #nanoparticle-drug-delivery #drug-release #nanoparticle-safety

One of the challenges is to determine the amount of drug loaded into the nanoparticles and the amount of freely available active compound. The fraction of active components is listed by the EMA as one of the parameters that must be provided for nano materials.

Traditionally, the method used for this analysis is HPLC coupled with UV-Vis or fluorescence detectors. It is normal that these procedures are linked to filtration steps, such as A4F (see: 202111301045 particle size distribution of medical nano-particles ). The challenge is that the during filtration and centrifugation, the analyte may be absorbed to the tubes. Moreover, these procedures may induce drug release.

A new method being employed is Analytical Ultracentrifugation ( AUC ). The molecular weigh is 5 orders of magnitude lower than that of the particles, therefore the sedimentation speed of the unbound molecules is much slower.