New Oral Coaxial Nanofibers for Gadodiamide-Prospective Intestinal Magnetic Resonance Imaging and Theranostic

Gadodiamide (GDD) is a widely used magnetic resonance imaging (MRI) contrast agent. It is available only as intravenous injection. Unfortunately, it exhibits a high renal toxicity. In this respect, the author investigated the possibility of developing nanofibers (NFs, one-dimensional (1D) nanostructures) of GDD that would be promising for oral administration in intestinal imaging. NFs are prepared by electrospinning technique in which a strong electrostatic field is applied on a polymer solution.

NFs were prepared by coaxial electrospinning technique using Eudragit S100 (ES 100) as a shell layer and GDD loaded with polyvinylpyrrolidone K90 (PVP K90) and hydroxypropyl-beta-cyclodextrin (HP-β-CyD) as core fibers. Compatibility study of the NFs ingredients was attested through ATR and DSC investigations. Thermogravimetric analysis of NFs was done to insure its stability. In vitro release of GDD in the intestinal medium with different pH values was measured. In vitro cytotoxicity test was done to prove its safety. Additionally, stability of NFs to perform its function was examined by X-ray.

NFs experienced high entrapment efficiency of about 94.3% ± 3.1%. The ingredients of NFs were compatible through FT-IR and DSC study. The in vitro release data of GDD from coaxial NFs were slow (˂14%) in pH 1.2 till 2 h, while at pH 7.4 it showed burst release of about 12% in the first 2 min. Thermogravimetric analysis proved the NFs are stable. The in vitro cytotoxicity study proved the safety of NFs. Using mammography, the coaxial NFs behaved the same as GDD plain indicating its ability to be a contrasting agent.

Coaxial NFs of GDD as a core with PVP K90 and HP-β-CyD and ES 100 as a shell were stable and efficient as oral imaging dosage form for the intestine. It might be a prospective theranostic.