NMR imaging investigations of drug delivery devices using a flow-through USP dissolution apparatus

A system for performing NMR imaging experiments on drug delivery devices within a flow-through dissolution apparatus, USP Apparatus 4, has been developed. The system was used to image the physical changes that occur in solid dosage forms during dissolution in the flow-through apparatus. Simultaneous cumulative drug release measurements were also made. The NMR images obtained under these conditions and the drug release data provide a better understanding of the processes involved in the release of drugs from drug delivery systems based on diffusion, dissolution and osmosis mechanisms.

Use of NMR imaging in the optimization of a compression-coated regulated release system

Nuclear magnetic resonance (NMR) imaging is routinely used to detect the protons of mobile water molecules within samples. In this investigation, this non-destructive, non-invasive technique was used to determine the cause for faster than predicted drug release from a dissolution-based regulated-release tablet. The NMR images of tablets, from two different formulations, taken at various intervals of time while immersed in static USP dissolution medium showed that the tablet with faster than predicted drug release had a porous coating. The porous coat exposed more of the core surface area to the dissolution medium than desired and this caused an increase in the rate of dissolution of the core. The data presented in this paper demonstrate the usefulness of NMR imaging in solid dosage form development.