Title : The role of cellulose nanofibers on co-encapsulation of probiotics and mesalazine in colon-specific microparticles for the treatment of ulcerative colitis: Encapsulation efficiency, morphology, and probiotic viability
Abstract:
Ulcerative colitis (UC), a chronic inflammatory bowel disease (IBD) affecting the colon and rectum, has an unknown etiology. Key symptoms include reduced pH, accelerated colonic transit, diarrhea, and imbalance in intestinal microbiota (dysbiosis). Probiotics (PBTs), when surviving the acidic stomach environment and reaching the intestines, can help restore intestinal microbiota balance and modulate local immune responses. Conventional medical treatment relies on the anti-inflammatory drug mesalazine (MLZ), which is rapidly and extensively absorbed in the upper gastrointestinal (GI) tract, causing various side effects, and exhibits low concentration in the target tissue (colon), reducing therapeutic efficacy. Thus, the co-encapsulation of PBTs and MLZ in colon-specific microparticles (MPs) is expected to provide protection for encapsulated compounds and vectorize release to the colon, aiming for localized treatment. Retrograded starch (RS), a fraction of starch that escapes digestion in the upper GI portions and is degraded by colonic microbiota, has been successfully used for constructing colon-specific systems. Cellulose nanofibers play an important role in increasing mechanical resistance and controlling drug release rates due to their high surface area and aspect ratio. Objective: To co-encapsulate the PBT Lactobacillus rhamnosus GG (Culturelle®) and MLZ using spray-drying with RS for a more effective and safer treatment of UC, and to evaluate performance. Methodology: RS was obtained through high amylose gelation/retrogradation in association with pectin. The resulting dispersions were supplemented with cellulose nanofibers, PBTs, and MLZ, and subjected to the drying process using a mini spray-dryer model B191 (Buchi). The obtained MPs were evaluated for encapsulation efficiency (EE), morphology, and probiotic viability using UV/VIS spectrophotometry, scanning electron microscopy (SEM), and plate counting on MRS medium, respectively. Results and Discussion: The obtained MPs exhibited an approximately spherical shape with a size of 10 μm, a satisfactory process yield (~60%), high EE (from 22.5 to 81.5%), and maintained the viability of PBTs, which was log 5.5 CFU/g of sample after 72 hours of production, conditioned at a temperature of 25°C. Conclusion: Spray-drying is a one-step drying and microencapsulation method, scalable and widely employed by the pharmaceutical industry. Fine-tuning of process variables, such as drying temperature and feed rate, allowed the production of colon-specific MPs with high EE and maintained viability, offering a more effective and safer treatment for UC patients.
Audience Take Away Notes:
- Role of Probiotics in Intestinal Bowel Disease Treatment
- Rationale for Co-encapsulation of Probiotics and Mesalazine
- Use of Colon-Specific Microparticles for targeting drugs to the inflamed colon
- Advantages of Spray-Drying to produce microparticles and
- How cellulose nanofibers can improve the performance of colon-specific microparticles
