Development of orally-deliverable DNA hydrogel by microemulsification and chitosan coating

In this study, we aimed to develop DNA hydrogel microspheres (Dgel-MS) coated with chitosan to improve their stability. Chitosan-coated Dgel-MS (Cs-Dgel-MS) was prepared by emulsifying Dgel to obtain the D-gel core, followed by mixing with microemulsions of chitosan for electrostatic coating. Fluorescence imaging of Cs-Dgel-MS labeled with fluorescent dyes showed that Dgel-MS (approximately 30 μm) was coated with chitosan. The recovery efficiency of Alexa Fluor 488-DNA was 87.4 ± 7.5%. To load a phosphorothioate CpG oligodeoxynucleotide into Dgel, a modified Dgel (mDgel) was designed and fluorescein isothiocyanate (FITC)-dextran was loaded into Cs-mDgel-MS as a model compound. The recovery efficiency of Alexa Fluor 488-CpG1668 and FITC-dextran was 83.3 ± 3.8% and 67.8 ± 4.6%, respectively. The release of Alexa Fluor 488-CpG1668 from Cs-mDgel-MS was slower than that from mDgel under acidic or DNase conditions. Intra-duodenal administration of FITC-dextran/Cs-mDgel-MS showed prolonged intestinal transition of the encapsulated FITC-dextran. These results indicate that Cs-Dgel-MS can be useful for oral delivery of CpG DNA and other bioactive compounds. Graphical abstract
Source: International Journal of Pharmaceutics - Category: Drugs & Pharmacology Source Type: research