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In-vitro analysis of APA microcapsules for oral delivery of live bacterial cells
1Biomedical Technology and Cell Therapy Research Laboratory, Department of Biomedical Engineering and Physiology, Artificial Cells and Organs Research Centre, Faculty of Medicine, McGill University, Montreal, Quebec, Canada.
Abstract:
Oral administration of microcapsules containing live bacterial cells has potential as an alternative therapy for several diseases. This article evaluates the suitability of the alginate-poly-L-lysine-alginate (APA) microcapsules for oral delivery of live bacterial cells, in-vitro, using a dynamic simulated human gastro-intestinal (GI) model. Results showed that the APA microcapsules were morphologically stable in the simulated stomach conditions, but did not retain their structural integrity after a 3-day exposure in simulated human GI media. The microbial populations of the tested bacterial cells and the activities of the tested enzymes in the simulated human GI suspension were not substantially altered by the presence of the APA microcapsules, suggesting that there were no significant adverse effects of oral administration of the APA microcapsules on the flora of the human gastrointestinal tract. When the APA microcapsules containing Lactobacillus plantarum 80 (LP80) were challenged in the simulated gastric medium (pH = 2.0), 80.0% of the encapsulated cells remained viable after a 5-min incubation; however, the viability decreased considerably (8.3%) after 15 min and dropped to 2.6% after 30 min and lower than 0.2% after 60 min, indicating the limitations of the currently obtainable APA membrane for oral delivery of live bacteria. Further in-vivo studies are required before conclusions can be made concerning the inadequacy of APA microcapsules for oral delivery of live bacterial cells.
Insights
Alginate-poly-L-lysine-alginate (APA) microcapsules showed initial stability in simulated stomach conditions but degraded in the gastrointestinal tract. This limits their effectiveness for oral delivery of live bacteria like Lactobacillus plantarum 80.
Area of Science:
- Biotechnology
- Microbiology
- Drug Delivery Systems
Background:
- Oral administration of live bacterial cells via microcapsules offers therapeutic potential.
- Alginate-poly-L-lysine-alginate (APA) microcapsules are being investigated for this purpose.
- Assessing microcapsule integrity and bacterial viability in simulated gastrointestinal conditions is crucial.
Purpose of the Study:
- To evaluate the suitability of APA microcapsules for in-vitro oral delivery of live bacterial cells.
- To assess the morphological stability and structural integrity of APA microcapsules in a simulated human gastrointestinal (GI) model.
- To determine the impact of APA microcapsules on the viability of encapsulated bacteria and the GI environment.
Main Methods:
- Utilized a dynamic simulated human GI model to mimic physiological conditions.
- Assessed APA microcapsule morphology and structural integrity under simulated gastric and intestinal environments.
- Quantified the viability of encapsulated Lactobacillus plantarum 80 (LP80) under simulated gastric conditions (pH 2.0) over time.
- Monitored microbial populations and enzyme activities in the simulated GI suspension.
Main Results:
- APA microcapsules maintained morphological stability in simulated stomach conditions.
- Structural integrity was compromised after 3 days in simulated human GI media.
- Encapsulated Lactobacillus plantarum 80 (LP80) viability decreased significantly in simulated gastric conditions, dropping from 80.0% at 5 min to <0.2% at 60 min.
- APA microcapsules did not substantially alter microbial populations or enzyme activities, indicating no significant adverse effects on gut flora.
Conclusions:
- APA microcapsules demonstrate limitations for effective oral delivery of live bacteria due to rapid degradation and low bacterial viability in simulated gastric conditions.
- Further in-vivo studies are necessary to definitively conclude the inadequacy of APA microcapsules for oral live bacterial cell delivery.
- The current APA microcapsule formulation requires significant improvement to ensure bacterial survival throughout the gastrointestinal tract.
