GMP-compliant batch manufacturing of dextran-coated iron oxide nanoparticles: A process development case study

Nanoparticles can be divided into several different classes. Within these classes, iron oxide-based nanoparticles exhibiting superparamagnetic properties occupy a special place because, in contrast to a majority of organic nanoparticles, they are magnetically accumulable and can be visualized in magnetic resonance imaging (MRI). In the course of extensive research over several years, the Section for Experimental Oncology and Nanomedicine (SEON) at the University Hospital of Erlangen has developed and fabricated superparamagnetic iron-oxide nanoparticles (SPION) termed SEON^Dex30. These particles consist of an iron oxide core of magnetite that over time partially oxidizes to maghemite, and an outer layer of cross-linked polysaccharide molecules (dextran). These SPIONs are intended to be employed in a clinical trial with the aim of providing evidence that they are superior to currently obtainable iron oxide nanoparticle medicinal products approved as MRI contrast media for liver imaging in terms of application safety, long-term tolerance and imaging quality. In order for a clinical trial center to be able to resort to SEON^Dex30 as an Investigational Medicinal Product (IMP) for human use, the particles must be manufactured according to Good Manufacturing Practice (GMP) guidelines. GMP-compliant development and production of nanomedicines requires in-depth knowledge of regulatory requirements and product-specific process technology as well as the availability of trained specialist staff, built-to-order manufacturing equipment and officially approved production areas. In the event that academic and clinical institutions lack the required financial, organisational and human resources to establish their own pharmaceutical production environment, it would seem reasonable to resort to specialised pharmaceutical companies that are able and willing to offer adequate procurement, manufacturing, quality control, certification and distribution services. Beyond the use of superparamagnetic nanoparticles as MRI contrast medium, further areas of application are being explored by SEON. In addition to dextran, other biocompatible and toxicologically safe materials such as proteins, lipids and polymers may also be used as coating agents. Functionalisation is achieved by attachment of active pharmaceutical ingredients (APIs) to the coated particle surface via chemical bonding techniques, resulting in the formation of API-loaded nanoparticles for magnetically-based accumulation, controlled drug release, targeted cancer therapies and several other application fields. The requirements on quality of starting materials, technology, production processes and quality inspections for finished SEON^Dex30 IMPs as described in this report may be seen as representative for other iron oxide-based nanoparticle medicinal products for human use to be developed and manufactured in the future. This article is intended as a process-oriented technical report illustrating GMP-compliant nanoparticle manufacturing using a representative case study, rather than as a comprehensive comparative review of nanoparticle platforms.