Pathways for Oral and Rectal Delivery of Gold Nanoparticles (1.7 nm) and Gold Nanoclusters into the Colon: Enteric-Coated Capsules and Suppositories.

Shabnam Hosseini,Oliver Wetzel,Kateryna Loza,Marc Heggen,Matthias Epple,Kathrin Kostka

doi:10.3390/molecules26165069

Shabnam Hosseini, Oliver Wetzel + Show 4 more

Open Access

https://doi.org/10.3390/molecules26165069

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Abstract

Two ways to deliver ultrasmall gold nanoparticles and gold-bovine serum albumin (BSA) nanoclusters to the colon were developed. First, oral administration is possible by incorporation into gelatin capsules that were coated with an enteric polymer. These permit the transfer across the stomach whose acidic environment damages many drugs. The enteric coating dissolves due to the neutral pH of the colon and releases the capsule’s cargo. Second, rectal administration is possible by incorporation into hard-fat suppositories that melt in the colon and then release the nanocarriers. The feasibility of the two concepts was demonstrated by in-vitro release studies and cell culture studies that showed the easy redispersibility after dissolution of the respective transport system. This clears a pathway for therapeutic applications of drug-loaded nanoparticles to address colon diseases, such as chronic inflammation and cancer.

Highlights

Colon-targeted drug delivery is required for the local treatment of a variety of bowel diseases, including amoebiasis, Crohn’s disease, colon cancer, and ulcerative colitis; local treatment of colon pathologies; and systemic delivery of protein and peptide drugs [1,2,3,4,5]
We have presented strategies for the oral and rectal transport of ultrasmall gold nanoparticles and of gold nanoclusters into the colon
In order to deliver theranostic nanoparticles and nanoclusters by oral intake and to protect them from gastric acid, they can be freeze-dried and put into a gelatin capsule that is coated with an enteric coating polymer

Summary

Introduction

Colon-targeted drug delivery is required for the local treatment of a variety of bowel diseases, including amoebiasis, Crohn’s disease, colon cancer, and ulcerative colitis; local treatment of colon pathologies; and systemic delivery of protein and peptide drugs [1,2,3,4,5]. Metal nanoparticles have been the subject of many studies in drug delivery and tumor therapy because of their versatile properties [9,10,11,12,13,14,15]. Unlike larger (plasmonic) nanoparticles, they show distinct autofluorescence, which is promising for imaging and theranostics [28,29]. They are typically prepared by reducing gold(+III) with a strong reducing agent, such as sodium borohydride, as demonstrated by Brust and Schiffrin et al in 1994 [30,31] (see [32], a review on these synthetic methods). Ultrasmall gold nanoparticles can cross the blood-brain barrier [27,35]

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