The efficacy of probiotic products depends on their viability throughout production, storage, and oral administration. This study optimized the formulation and processing of enteric-coated Lactobacillus reuteri (L. reuteri) pellets produced through extrusion-spheronization and fluidized-bed coating, employing a design of experiments (DOE) methodology. The ideal formulation consisted of 25% microcrystalline cellulose (MCC) and a 2:1 ratio of lactose to mannitol, satisfying criteria for disintegration, friability, and in vitro viability. The enteric coating process was refined using a coating percentage (X1) of 9% Eudragit® L 100–55, a pump rate (X2) of 10%, and an inlet temperature (X3) of 45 °C, resulting in a desirability of 0.993 for the prediction. The responses obtained from I-optimal design, a response surface methodology (RSM), were the viability of probiotics after the coating process (Y1) and after 2 h at pH 2 (Y2), both aligned with the applied mathematical model (p-value < 0.0001). The storage stability of the final formulation for 6 months indicated that 2–4 °C was the optimal temperature for preserving probiotics, while storage at room temperature (RT) caused a two-log reduction, although counts remained within the effective probiotic dose (<InlineEquation ID="IEq1"> <EquationSource Format="TEX">${10}^{6}$</EquationSource> <EquationSource Format="MATHML"><math> <msup> <mrow> <mn>10</mn> </mrow> <mn>6</mn> </msup> </math></EquationSource> </InlineEquation>–<InlineEquation ID="IEq2"> <EquationSource Format="TEX">${10}^{8}$</EquationSource> <EquationSource Format="MATHML"><math> <msup> <mrow> <mn>10</mn> </mrow> <mn>8</mn> </msup> </math></EquationSource> </InlineEquation> CFU/g per day). Macroscopic and microscopic study of colitis rats demonstrated the optimized formulation totally alleviated symptoms. The serum levels of inflammatory factors (interleukin 6 (IL-6) and tumor necrosis factor-alpha (TNF α)), as well as superoxide dismutase (SOD), were comparable to those in the dexamethasone-treated group. These findings identify optimum formulation and process factors that enhance probiotic viability and efficacy in developing resilient L. reuteri products.

An Experimental Design to Evaluate the Effects of Process and Formulation on the Viability and Efficacy of L. reuteri Enteric-Coated Pellets in a Rat Model with Colitis

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发表日期：

2025年10月15日

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Maedeh Shams Nouraei,
Nasrin Samadi,
Homa Faghihi,
Mohammad Sharifzadeh,
Fatemeh Moraffah,
Banafsheh Kiani-Dehkordi,
Maryam Tajabadi Ebrahimi,
Alireza Vatanara

摘要

The efficacy of probiotic products depends on their viability throughout production, storage, and oral administration. This study optimized the formulation and processing of enteric-coated Lactobacillus reuteri (L. reuteri) pellets produced through extrusion-spheronization and fluidized-bed coating, employing a design of experiments (DOE) methodology. The ideal formulation consisted of 25% microcrystalline cellulose (MCC) and a 2:1 ratio of lactose to mannitol, satisfying criteria for disintegration, friability, and in vitro viability. The enteric coating process was refined using a coating percentage (X₁) of 9% Eudragit® L 100–55, a pump rate (X₂) of 10%, and an inlet temperature (X₃) of 45 °C, resulting in a desirability of 0.993 for the prediction. The responses obtained from I-optimal design, a response surface methodology (RSM), were the viability of probiotics after the coating process (Y₁) and after 2 h at pH 2 (Y₂), both aligned with the applied mathematical model (p-value < 0.0001). The storage stability of the final formulation for 6 months indicated that 2–4 °C was the optimal temperature for preserving probiotics, while storage at room temperature (RT) caused a two-log reduction, although counts remained within the effective probiotic dose ( ${10}^{6}$ $10^{6}$ – ${10}^{8}$ $10^{8}$ CFU/g per day). Macroscopic and microscopic study of colitis rats demonstrated the optimized formulation totally alleviated symptoms. The serum levels of inflammatory factors (interleukin 6 (IL-6) and tumor necrosis factor-alpha (TNF α)), as well as superoxide dismutase (SOD), were comparable to those in the dexamethasone-treated group. These findings identify optimum formulation and process factors that enhance probiotic viability and efficacy in developing resilient L. reuteri products.