The nanoscale pores in metal-organic frameworks (MOFs) can be exploited to confine small molecular guests to yield Guest@MOF composite systems. One interesting avenue is to encapsulate drug molecules via nanoconfinement in the MOF pores, and triggering release on demand. However, there are challenges both in the capture and controlled release of guests. To this end, we would like to perform inelastic neutron scattering measurements at TOSCA to gain a better understanding of the underpinning mechanisms. The objectives are: (i) To determine the modification in collective terahertz vibrations, as a means to quantify the extent of host-guest confinement interaction; (ii) To study the role of size effects employing a systematic series of drug molecules; (iii) To elucidate how the binding of drug molecules to open metal sites may affect the broadband vibrational dynamics of drug@MOF systems.