Validation methods for encapsulated faecal microbiota transplantation: a scoping review.

Area of Science:

• Microbiology
• Gastroenterology
• Pharmacology

Background:

• Faecal microbiota transplantation (FMT) is a key therapy for intestinal microbiome dysbiosis, particularly *Clostridioides difficile* infection.
• Encapsulated FMT enhances patient accessibility and convenience compared to traditional methods.
• Standardized processing and robust validation protocols are crucial for encapsulated FMT efficacy and safety.

Purpose of the Study:

• To systematically review and describe published validation methods for encapsulated FMT.
• To identify key covariables and domains for assessing the quality of encapsulated FMT processing.
• To highlight the heterogeneity in current validation strategies and propose a quality assessment model.

Main Methods:

• A comprehensive scoping review was conducted using systematic searches in PubMed, Embase, and Web of Science.
• Studies reporting on encapsulated faecal formulations, including processing and validation, were included.
• Data on processing and validation methods were extracted and analyzed to develop a quality assessment model.

Main Results:

• Forty-four studies were included, identifying eight critical validation covariables: donor selection, pre-processing, preservation, oxygen-sparing processing, microbial count, viability, engraftment, and clinical outcomes.
• A three-domain model for quality assessment was constructed: Processing, Content Analysis, and Clinical Effect.
• No studies presented a reproducible capsule protocol, and validation strategies were found to be sparse and divergent.

Conclusions:

• The validation of FMT capsules is currently heterogeneous, necessitating the development of standardized processing protocols, with a focus on capsule content.
• A comprehensive quality assessment model encompassing processing, content analysis, and clinical effect is proposed.
• Future research should prioritize reporting of validation covariables to facilitate comparative assessments of encapsulated FMT clinical effects.