Gastric Simulated Conditions Research Articles

Antimicrobial susceptibility and sessile behaviour of bacteria isolated from a minimally processed vegetables plant

In this study, 20 heterotrophic bacteria from a minimally processed vegetables (MPV) plant were tested for their susceptibilities to five antibiotics (tetracycline, erythromycin, ampicillin, levofloxacin and ciprofloxacin), their (co)aggregation abilities and their survival under gastric simulated conditions. Peracetic acid (PA) and sodium hypochlorite (SH), both at 50 ppm, were evaluated for their abilities to control biofilms of these bacteria. In general, the Gram-negative bacteria were found to be more resistant to the selected antibiotics. Two isolates, Rhanella aquatilis and Stenotrophomonas maltophilia, demonstrated multidrug resistance. Only Rhodococcus erythropolis presented aggregation potential, while no bacterium survived under the gastric conditions. The biofilm experiments showed PA as less efficient than SH in killing biofilms and neither of the disinfectants was able to fully eliminate the biofilms. Significant regrowth was observed for most of the biofilms. The results indicate that alternative and/or complementary disinfection strategies are required to guarantee food safety.

Nanoencapsulation of dietary flavonoid fisetin: Formulation and in vitro antioxidant and α-glucosidase inhibition activities

The bioactive flavonoid fisetin (FS) is a diet-derived antioxidant that is being increasingly investigated for its health-promoting effects. Unfortunately, the poor physicochemical and pharmacokinetic properties affect and limit the clinical application.In this study, novel polymeric nanoparticles (NPs), based on Poly-(ε-caprolactone) (PCL) and PLGA-PEG-COOH, encapsulating FS were formulated as suitable oral controlled release systems. Results showed NPs having a mean diameter of 140–200nm, and a percent loading of FS ranging from 70 to 82%. In vitro release studies revealed that NPs are able to protect and preserve the release of FS in gastric simulated conditions, also controlling the release in the intestinal medium. Moreover, the DPPH and ABTS scavenging capacity of FS, as well as α-glucosidase inhibition activity, that resulted about 20-fold higher than commercial Acarbose, were retained during nanoencapsulation process.In summary, our developed NPs can be proposed as an attractive delivery system to control the release of antioxidant and anti-hyperglycemic FS for nutraceutical and/or therapeutic application.

Lipid nanoparticles as an emerging platform for cannabinoid delivery: physicochemical optimization and biocompatibility

This work aims at developing and optimizing a valuable oral delivery carrier for the cannabinoid derivative CB13, which presents a high therapeutic potential in chronic pain states that respond poorly to conventional analgesics, but also shows highly unfavorable physicochemical properties. CB13-loaded lipid nanoparticles (LNP) formulations were developed through solvent-emulsion evaporation and optimized in terms of physicochemical properties, long-term stability, integrity under gastric simulated conditions and in vitro interaction with NIH 3T3, HEK 293T and Caco-2 cells. An optimized formulation of LNP containing CB13 was obtained from a wide range of conditions assayed and analyzed. The selection of the lipid core, production conditions and the inclusion of lecithin proved to be key factors for the final properties of encapsulation, integrity and performance of the carriers. The LNP formulation proposed proved to be a promising carrier for the oral delivery of CB13, a cannabinoid with high therapeutic potential in chronic pain states that currently lack a valid oral treatment.

Estudio del comportamiento reológico in vitro de las fórmulas antirregurgitación

Introduction Thickened infant formulas, specially formulated to increase the viscosity, are commonly used in the treatment of regurgitation in the non-complicated gastroesophageal reflux. Objective To analyse viscosity and the rheological behaviour of different thickened standard formulas on the Spanish market compared to a standard formula with or without the addition of 10 g/100 mL of gluten-free cereals. Methods Viscosity of the samples was evaluated in a Bohlim CS-1o controlled-stress rheometer and was performed at basal conditions (25 °C, pH 7) and at simulated gastric conditions (37 °C, pH 4 and 10 g/100 mL of pepsin) at time 0, 30 and after 60 min of incubation. Values were expressed as centipoises (cp) (1cp=1/100 p). Results All formulas show a viscosity increase both in basal conditions and in gastric simulated conditions but the behaviour is very heterogeneous. Formulas containing bean gum (carob seed flour) with 2.9 g/100 g and a protein ratio similar to cow's milk (80 casein/20 whey) showed the highest and consistent viscosity (70 cp and 90 cp), with significant differences compared to the standard formula in all the measurements. When this thickener is in formulas with a protein ratio similar to breast milk (40 casein/60 whey) the viscosity was lower and reached 50 cp only with the thickener at a concentration of 4.7 gr/100 g, achieving significant differences versus standard formula. The formulas with starch thickeners (rice, potatoes and corn) achieved a lower and less consistent viscosity, with no significant difference. The viscosity reached after the addition of cereals both in basal conditions and in gastric simulated conditions was similar to that achieved with more effective thickeners. Lipid concentration is not involved in viscosity and rheological behaviour. Conclusion The viscosity of the thickened infant formula depends on the agent used, concentration and protein ratio. Not all reach a viscosity of 50 cp, hypothetical value to reach, since it doubles the viscosity of a standard formula. The ideal viscosity to be reached and the role of other components of the formula in the viscosity and rheological behaviour is still unclear.

Production of BSA-loaded alginate microcapsules: Influence of spray dryer parameters on the microcapsule characteristics and BSA release

The aim of this study was to optimize the production of BSA-loaded alginate microcapsules by spray drying and to study the release of bovine serum albumin fraction V (BSA) under gastric simulated conditions. Microcapsule yield, BSA release, microcapsule size and size distribution were characterized following the application of different production parameters including inlet air temperature, inlet air pressure and liquid feed rate. The microcapsules were incubated in 0.1 N HCl and BSA release was quantified over time. The yields were higher with the pressure of 3 bar compared to 4 bar and with a feed rate of 0.45 vs. 0.2 ml s−1. A high feed rate (0.45 vs. 0.2 ml s−1) allows one to obtain microcapsules with a low BSA release (p = 0.0327). The increase of the atomizer inlet temperature leads to microcapsules with a higher BSA release (p = 0.0230). A higher air pressure of 4 bar compared to 3 bar resulted in a lower microcapsule size (2.55 vs. 2.80 µm) and led to a narrower size distribution (0.92 vs. 1.07). In conclusion, the spray dryer parameters influenced the alginate microcapsule characteristics as well as subsequent protein release into a simulated gastric medium.

Production of BSA-loaded alginate microcapsules: Influence of spray dryer parameters on the microcapsule characteristics and BSA release

The aim of this study was to optimize the production of BSA-loaded alginate microcapsules by spray drying and to study the release of bovine serum albumin fraction V (BSA) under gastric simulated conditions. Microcapsule yield, BSA release, microcapsule size and size distribution were characterized following the application of different production parameters including inlet air temperature, inlet air pressure and liquid feed rate. The microcapsules were incubated in 0.1 N HCl and BSA release was quantified over time. The yields were higher with the pressure of 3 bar compared to 4 bar and with a feed rate of 0.45 vs. 0.2 ml s−1. A high feed rate (0.45 vs. 0.2 ml s−1) allows one to obtain microcapsules with a low BSA release (p = 0.0327). The increase of the atomizer inlet temperature leads to microcapsules with a higher BSA release (p = 0.0230). A higher air pressure of 4 bar compared to 3 bar resulted in a lower microcapsule size (2.55 vs. 2.80 µm) and led to a narrower size distribution (0.92 vs. 1.07). In conclusion, the spray dryer parameters influenced the alginate microcapsule characteristics as well as subsequent protein release into a simulated gastric medium.

Development and Comparison of Different Nanoparticulate Polyelectrolyte Complexes as Insulin Carriers

The overall objective of our research is to produce polyanion/chitosan nanoparticulate oral delivery systems for insulin. Specific objectives of the present study were to study dextran sulfate or alginate complexation with chitosan on mean particle size, insulin association efficiency, loading capacity and release profile. Nanoparticles were formed by ionotropic complexation and coacervation between polyanions (dextran sulfate and alginate) and chitosan. Diameter was evaluated with photon correlation spectroscopy, polymer interaction was confirmed by DSC and FTIR and particle morphology was assessed by SEM and TEM. Mean nanoparticle diameter ranged from 423 to 850 nm, insulin association efficiency from 63 to 94% and loading capacity from 5 to 13%. Dextran sulfate provided highest insulin association efficiency and retention of insulin in gastric simulated conditions. These nanoparticle systems show promise as insulin and potentially other therapeutic polypeptides carriers.

The combined use of triacylglycerols containing medium-chain fatty acids (MCFAs) and exogenous lipolytic enzymes as an alternative for nutritional antibiotics in piglet nutrition: I. In vitro screening of the release of MCFAs from selected fat sources by selected exogenous lipolytic enzymes under simulated pig gastric conditions and their effects on the gut flora of piglets

In a first set of experiments, it was examined if, with four selected medium-chain fatty acids (MCFAs) (C6:0–C12:0) containing fat sources (coconut, MCTAG1, MCTAG2, butter) and six lipases, under gastric simulated conditions (pH 3 to 6, 3 h incubation, 37°C, with complex substrate), appropriate amounts of MCFAs could be liberated, which could provide a valuable alternative for nutritional antibiotics used in piglet nutrition. Depending on the conditions applied, up to 20% of the MCFAs could be enzymatically released into the medium. In a second set of experiments, the generation and antimicrobial effects of MCFAs from three selected MCFA-containing fat sources (coconut, MCTAG1 and MCTAG2) and one appropriate microbial lipase, applied under different combinations and concentrations, were studied. A minimal concentration of 0.35 g per 100 g incubation fluid or 0.025 M MCFAs in the medium (e.g., stomach, proximal gut) appears to be necessary to obtain a significant (>10-fold) suppression of the flora. This amount can be obtained by choosing an appropriate combination of sources and doses of fat and lipases. The in vitro protocol used offers an excellent tool for the screening of the numerous combinations of MCFA-containing fat sources and lipolytic enzymes for their usefulness as feed supplements which comply with the above conditions, which are generally accepted as the prerequisite for obtaining growth promotion.