Cellulose Nanofibers Improve the Performance of Retrograded Starch/Pectin Microparticles for Colon-Specific Delivery of 5-ASA

Cellulose nanofibers (CNF) were employed as the nanoreinforcement of a retrograded starch/pectin (RS/P) excipient to optimize its colon-specific properties. Although starch retrogradation ranged from 32 to 73%, CNF addition discretely disfavored the RS yield. This result agrees with the finding that in situ CNF reduces the presence of the RS crystallinity pattern. A thermal analysis revealed that the contribution of pectin improves the thermal stability of the RS/CNF mixture. Through a complete factorial design, it was possible to optimize the spray-drying conditions to obtain powders with high yield (57%) and low moisture content (1.2%). The powders observed by Field Emission Gum Scanning Electron Microscopy (FEG-SEM) had 1–10 µm and a circular shape. The developed methodology allowed us to obtain 5-aminosalicilic acid-loaded microparticles with high encapsulation efficiency (16–98%) and drug loading (1.97–26.63%). The presence of CNF in RS/P samples was responsible for decreasing the burst effect of release in simulated gastric and duodenal media, allowing the greatest mass of drug to be targeted to the colon. Considering that spray-drying is a scalable process, widely used by the pharmaceutical industry, the results obtained indicate the potential of these microparticles as raw material for obtaining other dosage forms to deliver 5-ASA to the distal parts of gastrointestinal tract, affected by inflammatory bowel disease.

Baseline Insulin Levels may Predict Response to Low Glycemic Index Complete Nutrition Formula: A Randomized Cross-Over Control Trial

Background: Personalized intervention is crucial for effective nutritional advice to prevent diabetes. However, specific characters of the responders to low glycemic index (low GI) diet was unclear. This study was aimed to identify glycemic index and factors affecting response to the low glycemic complete nutrition formula.Method: A randomized cross-over controlled trial was conducted in 18 healthy volunteers (fasting plasma glucose < 100 mg/dL). All participants consumed complete nutrition drink with retrograded starch, glucose solution and white bread (35 g carbohydrate each) in a random sequence with 14-day wash-out intervals. The GI value of complete nutrition drink was determined from area under the curve (AUCi) of postprandial glucose, using glucose solution and white bread as references. Baseline characters of responders (with low GI of complete nutrition drink) and non-responders were compared and correlated to identify factors affecting their responses to the low GI complete nutrition drink. Results: The adjusted GIs for complete nutrition drink with retrograded starch were 48.2 ± 10.4 and 46.7 ± 12.7 when using glucose solution and white bread as the reference food, respectively. Baseline insulin level was the only parameter showing difference between responders and non-responders. The response correlated with baseline insulin (r = 0.4997, p = 0.0347), but was independent of fasting plasma glucose (r = 0.0456, p = 0.8574) and others. Conclusions: In healthy volunteers with normal blood glucose levels, adequate baseline insulin level was the only factor correlated with the response to low glycemic complete nutrition drink. Screening for fasting insulin level may be encouraged for personalized nutrition of low GI diet.Trial registration: TCTR, TCTR20210305001. Registered 4 March 2021 - Retrospectively registered, http://www.thaiclinicaltrials.org/ TCTR20210305001

Ionic Cross-Linking as a Strategy to Modulate the Properties of Oral Mucoadhesive Microparticles Based on Polysaccharide Blends

Polymer blends of gellan gum (GG)/retrograded starch(RS) and GG/pectin (P) were cross-linked with calcium, aluminum, or both to prepare mucoadhesive microparticles as oral carriers of drugs or nano systems. Cross-linking with different cations promoted different effects on each blend, which can potentially be explored as novel strategies for modulating physical–chemical and mucoadhesive properties of microparticles. Particles exhibited spherical shapes, diameters from 888 to 1764 µm, and span index values lower than 0.5. Blends of GG:P cross-linked with aluminum resulted in smaller particles than those obtained by calcium cross-linking. GG:RS particles exhibited larger sizes, but cross-linking this blend with calcium promoted diameter reduction. The uptake rates of acid medium were lower than phosphate buffer (pH 6.8), especially GG:RS based particles cross-linked with calcium. On the other hand, particles based on GG:P cross-linked with calcium absorbed the highest volume of acid medium. The percentage of systems erosion was higher in acid medium, but apparently occurred in the outermost layer of the particle. In pH 6.8, erosion was lower, but caused expressive swelling of the matrixes. Calcium cross-linking of GG:RS promoted a significantly reduction on enzymatic degradation at both pH 1.2 and 6.8, which is a promising feature that can provide drug protection against premature degradation in the stomach. In contrast, GG:P microparticles cross-linked with calcium suffered high degradation at both pH values, an advantageous feature for quickly releasing drugs at different sites of the gastrointestinal tract. The high mucoadhesive ability of the microparticles was evidenced at both pH values, and the Freundlich parameters indicated stronger particle–mucin interactions at pH 6.8.

Jet-cooked papermaking starches studied using 1H NMR-relaxometry and viscometry

Two wet-end starches (potato and barley), one surface sizing starch (barley) and one coating binder starch (barley) were jet-cooked. Samples were collected and stored at 90, 60 and 40 °C. 1H NMR-relaxometry and viscometry were used to monitor the jet-cooked solutions as they cooled to room temperature. Samples stored at different temperatures were also monitored using 1H NMR-relaxometry and viscometry. A sediment formed into the surface sizing and coating binder starches stored at 90 °C. The sediment and supernatant were separated and collected, and measured using 1H NMR-relaxometry. The {T_{2}} relaxation rates of jet-cooked starches showed significant differences between potato and barley starches, as had also been examined in previous studies. The NMR method was also sensitive to differences in solids content and chemical modification (degree of cationization, degree of oxidation and molecular weight). The cooking temperature, cooking speed and viscosity did not influence {T_{2}} relaxation rates. The sediment separated from the surface sizing and coating binder starches held at 90 °C had a significantly higher relaxation rate than the supernatant, indicating that the sediment contained a high amount of retrograded starch.