Protein Digestion and Quality of Goat and Cow Milk Infant Formula and Human Milk Under Simulated Infant Conditions.

OBJECTIVE: The aim of this study was to determine the kinetics of true ileal protein digestion and digestible indispensable amino acid score (DIAAS) of a goat milk-based infant formula (GIF), a cow milk-based infant formula (CIF), and human milk (HM). METHODS: The GIF, CIF, and HM were investigated in an in vitro gastrointestinal model simulating infant conditions. Digested compounds were dialyzed from the intestinal compartment as bioaccessible fraction. Dialysate was collected in 15 to 60-minute periods for 4 hours. True ileal protein digestibility and DIAAS were determined as bioaccessible nitrogen (N) and amino acids. RESULTS: N bioaccessibility from the GIF showed similar kinetics to that of HM. The CIF showed a delay in N bioaccessibility versus the GIF and HM. In the 1st hour of digestion, N bioaccessibility was 19.9% ±â€Š3.5% and 23.3% ±â€Š1.3% for the GIF and HM, respectively, and 11.2% ±â€Š0.6% for CIF (P < 0.05 vs HM). In the 3rd hour of digestion, the N bioaccessibility was higher (P < 0.05) for the CIF (28.9% ±â€Š1.2%) than for the GIF (22.5% ±â€Š1.6%) and HM (20.6% ±â€Š1.0%). After 4 hours, the true ileal protein digestibility of the GIF, CIF, and HM was 78.3% ±â€Š3.7%, 73.4% ±â€Š2.7%, and 77.9% ±â€Š4.1%, respectively. The DIAAS for the GIF, CIF, and HM for 0- to 6-month-old infants was 83%, 75%, and 77% for aromatic AA. CONCLUSION: The protein quality is not different between the GIF, CIF, and HM, but the kinetics of protein digestion of the GIF is more comparable to that of HM than that of the CIF.

Increased bioavailability of celecoxib under fed versus fasted conditions is determined by postprandial bile secretion as demonstrated in a dynamic gastrointestinal model.

The objective of this study was to utilize physiologically relevant dynamic dissolution testing with the TNO intestinal model (TIM-1) in vitro gastrointestinal model to investigate the bioaccessibility of celecoxib. A single 200-mg dose of celecoxib was evaluated under average adult human physiological conditions simulated in the TIM-1 system. The in vitro data were compared with the clinically established pharmacokinetic data. When expressed as a percent of drug that progresses from the duodenum to the jejunum and ileum compartments (bioaccessible sites), the study demonstrated a 2-fold increase in the total bioaccessibility for celecoxib when co-administered with a high-fat meal as opposed to co-administration with a glass of water (fasted conditions). That increase in bioaccessibility was similar to a 1.2 to 1.6-fold increase in systemic exposure in adults and children following co-administration with a high-fat meal when compared to the exposure measured when celecoxib was co-administered with only water. Following that comparison, the flexibility of the TIM-1 system was used to more specifically investigate individual parameters of gastrointestinal conditions, such as the rate of bile secretion (emptying of the bile bladder) that accompanies high-fat meal consumption. We demonstrated that increased bile secretion after co-administration of a high-fat meal played a more important role in the increased celecoxib bioaccessibility than did the food matrix. This indicates that in humans without a bile bladder the exposure of celecoxib administered with food might be as low as under fasted state.

Bioprocessing of wheat bran in whole wheat bread increases the bioavailability of phenolic acids in men and exerts antiinflammatory effects ex vivo.

Whole grain consumption has been linked to a lower risk of metabolic syndrome, which is normally associated with a low-grade chronic inflammation. The benefits of whole grain are in part related to the inclusion of the bran, rich in phenolic acids and fiber. However, the phenols are poorly bioaccessible from the cereal matrix. The aim of the present study was to investigate the effect of bioprocessing of the bran in whole wheat bread on the bioavailability of phenolic acids, the postprandial plasma antioxidant capacity, and ex vivo antiinflammatory properties. After consumption of a low phenolic acid diet for 3 d and overnight fasting, 8 healthy men consumed 300 g of whole wheat bread containing native bran (control bread) or bioprocessed bran (bioprocessed bread) in a cross-over design. Urine and blood samples were collected for 24 h to analyze the phenolic acids and metabolites. Trolox equivalent antioxidant capacity was measured in plasma. Cytokines were measured in blood after ex vivo stimulation with LPS. The bioavailabilities of ferulic acid, vanillic acid, sinapic acid, and 3,4-dimethoxybenzoic acid from the bioprocessed bread were 2- to 3-fold those from the control bread. Phenylpropionic acid and 3-hydroxyphenylpropionic acid were the main colonic metabolites of the nonbioaccessible phenols. The ratios of pro-:antiinflammatory cytokines were significantly lower in LPS-stimulated blood after the consumption of the bioprocessed bread. In conclusion, bioprocessing can remarkably increase the bioavailability of phenolic acids and their circulating metabolites, compounds which have immunomodulatory effects ex vivo.

Effect of bioprocessing of wheat bran in wholemeal wheat breads on the colonic SCFA production in vitro and postprandial plasma concentrations in men.

The health benefits of whole grain consumption can be partly attributed to the inclusion of the bran or outer-layers of the grain rich in dietary fibre. Fibre is fermented in the colon, leading to the production of beneficial metabolites, such as short-chain fatty acids (SCFA). The effect of five different types of bread on the SCFA production was studied in an in vitro model of human colon. Additionally, the postprandial effects of two selected breads on the SCFA plasma concentrations were investigated in men. A higher in vitro production of butyrate was induced by wholemeal wheat bread with bioprocessed bran than by native bran. The increase in butyrate seemed to be in exchange for propionate, whilst the total SCFA production remained similar. However, differences between the two breads in the postprandial butyrate concentrations could not be detected in peripheral blood of men, probably due to an effective utilisation by colonocytes.

On the usefulness of compendial setups and tiny-TIM system in evaluating the in vivo performance of oral drug products with various release profiles in the fasted state: Case example sodium salt of A6197.

We evaluated the usefulness of quality control dissolution data collected with compendial Apparatus I and II, biorelevant dissolution data collected with compendial apparatus IV, and bioaccessibility data collected with the non-compendial tiny-TIM system in screening modified release formulations during the development of BCS Class I compounds using a Boehringer Ingelheim model experimental compound, A6197. Four products were investigated: an immediate release tablet, an extended release tablet, modified release mini-tablets, and extended release pellets. Data with modified release products collected with the compendial apparatus were evaluated vs. the average intraluminal dissolution estimated after deconvoluting clinical data collected in healthy adults. Data collected with the tiny-TIM system were evaluated vs. the average AUC and Cmax values estimated from the clinical data. Unlike with the quality control data collected with Apparatus I and II, data collected with Apparatus IV data and Level I biorelevant media adequately described the intraluminal dissolution process of the three modified release products. Data deviated less than 10% from the actual average deconvoluted intraluminal dissolution profiles, illustrating the usefulness of Apparatus IV biorelevant data in understanding the intraluminal dissolution process of BCS class I small molecules administered as modified release products in the fasted state. Total bioaccessibility data and maximum bioaccessibility data collected using the tiny-TIM and the immediate release tablet and the three modified release drug products correctly reproduced the ranking of A6197 AUC values (R2 = 0.989) and Cmax values (R2 = 0.962), respectively, illustrating tiny-TIM as a useful system for formulation selection of BCS class I small molecules administered in the fasted state.

Survival of Mycobacterium bovis BCG oral vaccine during transit through a dynamic in vitro model simulating the upper gastrointestinal tract of badgers.

In developing an oral bait BCG vaccine against tuberculosis in badgers we wanted to understand the conditions of the gastrointestinal tract and their impact on vaccine viability. Conditions mimicking stomach and small-intestine caused substantial reduction in BCG viability. We performed in vivo experiments using a telemetric pH monitoring system and used the data to parameterise a dynamic in vitro system (TIM-1) of the stomach and small intestine. Some BCG died in the stomach compartment and through the duodenum and jejunum compartments. BCG survival in the stomach was greatest when bait was absent but by the time BCG reached the jejunum, BCG viability was not significantly affected by the presence of bait. Our data suggest that from a starting quantity of 2.85 ± 0.45 x 108 colony-forming units of BCG around 2 log10 may be killed before delivery to the intestinal lymphoid tissue. There are economic arguments for reducing the dose of BCG to vaccinate badgers orally. Our findings imply this could be achieved if we can protect BCG from the harsh environment of the stomach and duodenum. TIM-1 is a valuable, non-animal model with which to evaluate and optimise formulations to maximise BCG survival in the gastrointestinal tract.

Appetite ratings of foods are predictable with an in vitro advanced gastrointestinal model in combination with an in silico artificial neural network.

The expected increase of global obesity prevalence makes it necessary to have information about the effects of meal intakes on the feeling of appetite. Because human clinical studies are time and cost intensive, there is a need for a reliable alternative. The aim of this study was to develop and evaluate an in vitro-in silico technology to predict the feelings of fullness and hunger after consumption of different types of meals. In this technology the results from an in vitro gastrointestinal model (tiny-TIMagc) on gastric viscosity and intestinal digestion of different meals were used as input data for an in silico artificial neural network (ANN). The predictions of the feeling of fullness and hunger were compared with actual human scores for these parameters after intake of the same type of meals. From these first series of experiments, with a relatively small number of in vitro digestive parameters as input for in silico modeling, a reasonable prediction of appetite rating for foods can be realized at a time- and cost-effective way.

Assessment of the multi-mycotoxin-binding efficacy of a carbon/aluminosilicate-based product in an in vitro gastrointestinal model.

A laboratory model, set to simulate the in vivo conditions of the porcine gastrointestinal tract, was used to study the small intestinal absorption of several mycotoxins and the effectiveness of Standard Q/FIS (a carbon/aluminosilicate-based product) in reducing mycotoxin absorption when added to multitoxin-contaminated diets. Mycotoxins were quickly absorbed in the proximal part of the small intestine at levels of 105 and 89% for fumonisins B1 and B2, respectively, 87% for ochratoxin A, 74% for deoxynivalenol, 44% for aflatoxin B1, and 25% for zearalenone. Addition of Standard Q/FIS to the diet (up to 2%, w/w) significantly reduced mycotoxin absorption, in a dose-dependent manner, up to 88% for aflatoxin B1, 44% for zearalenone, and 29% for the fumonisins and ochratoxin. Standard Q/FIS was ineffective in reducing deoxynivalenol uptake. These findings suggest that Standard Q/FIS can be used as a multitoxin adsorbent material to prevent the individual and combined adverse effects of mycotoxins in animals.

Malondialdehyde and 4-hydroxy-2-hexenal are formed during dynamic gastrointestinal in vitro digestion of cod liver oils.

Marine long-chain polyunsaturated fatty acids (LC n-3 PUFA) are associated with reduced risk for inflammatory diseases, such as cardiovascular diseases and rheumatoid arthritis. These fatty acids, however, are rapidly oxidized, generating highly reactive malondialdehyde (MDA), 4-hydroxy-2-hexenal (HHE) and 4-hydroxy-2-nonenal (HNE). These oxidation products may interact with DNA and proteins, thus possibly leading to impaired cell functions. Little is known about the formation of MDA, HHE and HNE in fish oil in the gastrointestinal (GI) tract. In this study, the effect of dynamic in vitro digestion of cod liver oil on the generation of MDA, HHE and HNE was evaluated using the TNO Gastro-Intestinal Model (tiny-TIM). Effects of pre-formed oxidation products, pre-emulsification of the oil, and addition of oxidants (EDTA and hemoglobin, Hb) on GI oxidation were evaluated. Formation of aldehydes occurred during GI digestion. However, only emulsified oil fortified with 11.5 µM Hb oxidized to a degree that overcame the dilution induced by gastric secretion, which caused increased aldehyde concentrations in gastric lumen up to 90 min. The maximum levels of aldehydes generated in this study were 24.5 µM MDA, 1.6 µM HHE and 0.07 µM HNE. Oils containing different amounts of pre-formed lipid oxidation products maintained the same oxidation ranking order during digestion, even though the relative changes were not directly proportional. Emulsification of the oil had an unclear effect in the gastric phase, but a pro-oxidative effect in the intestinal phase. In general, higher aldehyde levels were reached in the intestinal lumen than in the initial meal, demonstrating that GI digestion promotes oxidation. Hence, epithelial cells may be exposed to elevated amounts of reactive aldehydes for several hours after a meal containing fish oil.

Formation of malondialdehyde (MDA), 4-hydroxy-2-hexenal (HHE) and 4-hydroxy-2-nonenal (HNE) in fish and fish oil during dynamic gastrointestinal in vitro digestion.

Marine lipids contain a high proportion of polyunsaturated fatty acids (PUFA), including the characteristic long chain (LC) n-3 PUFA. Upon peroxidation these lipids generate reactive products, such as malondialdehyde (MDA), 4-hydroxy-2-hexenal (HHE) and 4-hydroxy-2-nonenal (HNE), which can form covalent adducts with biomolecules and thus are regarded as genotoxic and cytotoxic. PUFA peroxidation can occur both before and after ingestion. The aim of this study was to determine what levels of MDA, HHE and HNE can evolve in the gastric and intestinal lumen after ingesting meals containing fish or fish oil using a dynamic gastrointestinal (GI) model (TIM). The impact of the fish muscle matrix, lipid content, fish species, and oven baking on GI oxidation was evaluated. MDA and HHE concentrations in gastric lumen increased for all meals during digestion, with the highest level found with herring mince; ∼ 25 µM MDA and ∼ 850 nM HHE. Aldehyde concentrations reached in intestinal lumen during digestion of fish containing meals were generally lower than in gastric lumen, while isolated herring oils (bulk and emulsified) generated higher MDA and HHE values in intestinal lumen compared to gastric lumen. Based on aldehyde levels in gastric lumen, meals containing herring lipids were ranked: raw herring (17% lipid) = baked herring (4% lipid) > raw herring (4% lipid) ≫ herring oil emulsion > herring oil. Herring developed higher concentrations of MDA and HHE during gastric digestion compared to salmon, which initially contained lower levels of oxidation products. Cooked salmon generated higher MDA concentrations during digestion than raw salmon. Low levels of HNE were observed during digestion of all test meals, in accordance with the low content of n-6 PUFA in fish lipids.

Evaluation of two dynamic in vitro models simulating fasted and fed state conditions in the upper gastrointestinal tract (TIM-1 and tiny-TIM) for investigating the bioaccessibility of pharmaceutical compounds from oral dosage forms.

Pharmaceutical research needs predictive in vitro tools for API bioavailability in humans. We evaluated two dynamic in vitro gastrointestinal models: TIM-1 and tiny-TIM. Four low-soluble APIs in various formulations were investigated in the TIM systems under fasted and fed conditions. API small-intestinal bioaccessibility profiles were evaluated between the two systems and in comparison with human data. Both TIM systems showed a higher bioaccessibility of ciprofloxacin and nifedipine during 3-4h after dosing immediate release (IR) compared to modified release (MR) formulations. Higher bioaccessibility levels from IR formulations were observed under fasted state in the first 30-90 min in tiny-TIM as compared to TIM-1, resulting in a tmax similar to clinical data. Absence (ciprofloxacin) or presence (posaconazole) of a food effect on bioaccessibility was observed in both TIM systems in line with human data. A higher bioaccessibility of fenofibrate from nano- vs micro-particle formulation was found in both TIM systems. This dataset shows the predictive quality of the TIM systems for clinical data on API small-intestinal bioaccessibility from IR and MR formulations and food effects. Tiny-TIM provides higher throughput and better prediction for IR formulations. TIM-1 provides detailed information on site-specific release of APIs, relevant for MR formulations and food effects.

Herring roe protein has a high digestible indispensable amino acid score (DIAAS) using a dynamic in vitro gastrointestinal model.

It is hypothesized that the digestible indispensable amino acid score (DIAAS) can be determined based on dynamic in vitro gastrointestinal digestion experiments as replacement for invasive animal studies. We determined the in vitro DIAAS for immature herring eggs (roe) proteins in comparison with reference proteins. The true ileal digestibility of protein and indispensable amino acids (IAA) was measured under human conditions simulated in a gastrointestinal model (tiny-TIM). The in vitro true ileal digestibility of ovalbumin, cooked and raw chicken egg white, and casein was similar to that found in humans (r(2) = 0.96), providing a casual observation to support the validity of tiny-TIM. The digestibility of the immature herring egg proteins was 71% to 92%. The highest IAA digestibility was found for immature whole herring egg protein (55%-80%) in comparison to immature herring egg membrane and immature de-membraned herring protein (50%-70%). The DIAAS as recommended by FAO for children and adults, but measured in vitro, were 91% for immature whole herring egg protein (lysine first limiting), 71% for immature herring egg membrane protein (histidine first limiting), and 88% for immature herring egg de-membraned protein (sulfur AA first limiting). True ileal protein and amino acid digestibility can be determined in a dynamic gastrointestinal model, such as tiny-TIM, which can be used for estimating the DIAAS. Immature herring egg proteins, a previously underutilized resource, were determined to be an important and valuable source of IAA for human consumption.

Evaluation of the intestinal absorption of deoxynivalenol and nivalenol by an in vitro gastrointestinal model, and the binding efficacy of activated carbon and other adsorbent materials.

In vitro screening of 14 adsorbent materials, including some commercial products used to detoxify Fusarium-mycotoxins, were tested in the pH range of 3-8 for deoxynivalenol (DON)- and nivalenol (NIV)-binding ability. Only activated carbon showed to be effective with binding capacities of 35.1 micromol and 8.8 micromol DON and NIV/g adsorbent, respectively, calculated from the adsorption isotherms. A dynamic laboratory model simulating the gastrointestinal (GI) tract of healthy pigs (TIM system) was used to evaluate the small-intestinal absorption of DON and NIV and the efficacy of activated carbon in reducing the relevant absorption. The in vitro intestinal absorptions of DON and NIV were 51% and 21%, respectively, as referred to 170 microg DON and 230 microg NIV ingested through contaminated (spiked) wheat. Most absorption occurred in the jejunal compartment for both mycotoxins. The inclusion of activated carbon produced a significant reduction in the intestinal mycotoxin absorption. At 2% inclusion level the absorption with respect to the intake was lowered from 51% to 28% for DON and from 21% to 12% for NIV. The binding activity of activated carbon for these trichothecenes was lower than that observed for zearalenone, a mycotoxin frequently co-occurring with them in naturally contaminated cereals.

Assessing the zearalenone-binding activity of adsorbent materials during passage through a dynamic in vitro gastrointestinal model.

A novel approach is presented herein to study the intestinal absorption of mycotoxins by using a laboratory model that mimics the metabolic processes of the gastrointestinal (GI) tract of healthy pigs. This model was used to evaluate the small-intestinal absorption of zearalenone from contaminated wheat (4.1 mg/kg) and the effectiveness of activated carbon and cholestyramine at four inclusion levels (0.25, 0.5, 1 and 2%) in reducing toxin absorption. Approximately 32% of ZEA intake (247 microg) was released from the food matrix during 6 h of digestion and was rapidly absorbed at intestinal level. A significant reduction of intestinal absorption of ZEA was found after inclusion of activated carbon or cholestyramine, even at the lowest dose of adsorbents, with a more pronounced effect exhibited by activated carbon. In particular, when 2% of activated carbon or cholestyramine was added to the meal the ZEA intestinal absorption was lowered from 32% of ZEA intake to 5 and 16%, respectively. The sequestering effect of both adsorbents took place already during the first 2 h of digestion and persisted during the rest of the experiment. The GI-model is a rapid and physiologically relevant method to test the efficacy of adsorbent materials in binding mycotoxins and can be used to pre-screen mycotoxin/adsorbent combinations as an alternative to animal experiments.

Intragastric formation and modulation of N-nitrosodimethylamine in a dynamic in vitro gastrointestinal model under human physiological conditions.

Human exposure to carcinogenic N-alkylnitrosamines can occur exogenously via food consumption or endogenously by formation of these compounds through nitrosation of amine precursors. Information on the intragastric formation of NDMA from complex mixtures of precursors and inhibitors in humans is not available. In this study the formation of N-nitrosodimethylamine (NDMA) has been quantitatively analysed in a dynamic in vitro gastrointestinal model, in which gastric conditions can be modulated and closely simulates the physiological situation in humans. Substantial amounts of NDMA were produced when nitrite and dimethylamine or codfish were simultaneously introduced into the model. However, humans are gradually exposed to nitrite by the intake of nitrate-containing food. Nitrate secreted in saliva is converted to nitrite by oral bacteria. To mimic the human exposure to nitrite in a realistic way, nitrite was gradually added into the gastric compartment, simulating the swallowing of nitrite containing oral fluid after the intake of nitrate at the level of 0.1-10 times the ADI. Under these conditions, the cumulative amounts of NDMA formed were 2.3-422 microg NDMA and 1.8-42.7 microg NDMA at a rapid and slow gastric pH decrease, respectively. Beside codfish, various fish species and batches in combination with nitrite, simulating the intake of for times the ADI of nitrate, were investigated. Herring, pollack and plaice were also able to induce NDMA formation. Mackerel, salmon and pike perch did not result in increased NDMA formation. Furthermore, the effect of nitrosation modulators on NDMA formation was investigated. Thiocyanate (2 mM) increased NDMA formation, but the increase was not statistically significant. In contrast, orange jus and tea effectively, but not totally, reduced the amount of NDMA formed in the gastric compartment. These experiments show that (1). the dynamic in vitro gastrointestinal model is an appropriate tool for mechanistic studies on the intragastric formation of nitrosamines, and (2). that the results obtained with this model are helpful in evaluating human cancer risk for the combined intake of codfish-like fish species and nitrate-containing vegetables.

Effects of a high fat meal matrix and protein complexation on the bioaccessibility of blueberry anthocyanins using the TNO gastrointestinal model (TIM-1).

The TNO intestinal model (TIM-1) of the human upper gastrointestinal tract was used to compare intestinal absorption/bioaccessibility of blueberry anthocyanins under different digestive conditions. Blueberry polyphenol-rich extract was delivered to TIM-1 in the absence or presence of a high-fat meal. HPLC analysis of seventeen anthocyanins showed that delphinidin-3-glucoside, delphinidin-3-galactoside, delphinidin-3-arabinoside and petunidin-3-arabinoside were twice as bioaccessible in fed state, whilst delphinidin-3-(6″-acetoyl)-glucoside and malvidin-3-arabinoside were twice as bioaccessible under fasted conditions, suggesting lipid-rich matrices selectively effect anthocyanin bioaccessibility. TIM-1 was fed blueberry juice (BBJ) or blueberry polyphenol-enriched defatted soybean flour (BB-DSF) containing equivalent amounts of free or DSF-sorbed anthocyanins, respectively. Anthocyanin bioaccessibility from BB-DSF (36.0±10.4) was numerically, but not significantly, greater than that from BBJ (26.3±10.3). Ileal efflux samples collected after digestion of BB-DSF contained 2.8-fold more anthocyanins than same from BBJ, suggesting that protein-rich DSF protects anthocyanins during transit through upper digestive tract for subsequent colonic delivery/metabolism.

The bioaccessibility of eicosapentaenoic acid was higher from phospholipid food products than from mono- and triacylglycerol food products in a dynamic gastrointestinal model.

The bioaccessibility of eicosapentaenoic acid (EPA) in the forms of monoacylglycerol (EPA-MAG), triacylglycerol (EPA-TAG), and phospholipid (EPA-PL) during gastrointestinal passage was compared in this study using a dynamic gastrointestinal model (TIM system). The TIM system simulated the average upper gastrointestinal tract conditions of healthy human adults after intake of a meal (fed state conditions). In this study, the three EPA-rich oils were separately homogenized with full fat milk to obtain oil-in-water emulsions. Plain yogurt was added into the mixture at an emulsion/yogurt ratio of 4:1 (w/w) as the food matrix of the test products. The results show that the test meals containing EPA-PL left the stomach compartment most efficiently in comparison with the gastric emptying of EPA-MAG and EPA-TAG. The PLs also showed a significantly (P < 0.05) higher bioaccessibility of EPA (75-80%) in comparison with MAG (30%) and TAG (38%). The better gastric emptying of EPA-PL was likely related to the more stable emulsion of EPA-PL in the test meal. EPA-PL was delivered within the meal matrix into the duodenum instead of floating on the top of the test meal matrix. EPA-MAG had the highest amount of EPA that did not leave the stomach (68% of the test meal). The results from this work indicate that EPA-PL is a more effective form of EPA for a higher lipid bioaccessibility than MAG and TAG under the test conditions.

Digestibility of transglutaminase cross-linked caseinate versus native caseinate in an in vitro multicompartmental model simulating young child and adult gastrointestinal conditions.

Aim of this study was to investigate the digestion of transglutaminase cross-linked caseinate (XLC) versus native caseinate (NC) in solution and in cheese spread under digestive conditions for adults and children mimicked in a gastrointestinal model. Samples were collected for gel electrophoresis and nitrogen analysis. The results showed no relevant differences between XLC and NC for total and α-amino nitrogen in digested fraction under adult and child conditions. However, the rate of digestion was depending on the food matrix. Gel electrophoresis showed the gastric breakdown of XLC without formation of pepsin resistant peptides larger than 4 kDa. NC was slowly digested in the stomach with formation of pepsin resistant fragments and was still detectable in the stomach after 90 min. In the small intestine the proteins were rapidly digested. XLC was digested to small peptides, while NC was resistant against pepsin digestion under gastric conditions of adults and children.

In vitro gastrointestinal model (TIM) with predictive power, even for infants and children?

There is a need for information on the bioavailability in pediatric patients of drugs from manipulated dosage forms when applied in combination with food and/or co-medication under realistic daily practice circumstances. We describe the development, validation and application of a dynamic, computer-controlled in vitro system mimicking the conditions in the upper gastrointestinal tract of neonates, infants and toddlers: TIMpediatric. Paracetamol and diclofenac in age-related food matrices and with esomeprazole co-medication were tested. The experiments showed relevant results on the impact of drug manipulation and co-medication on the availability for absorption of active compounds. Without ethical constraints, alternative approaches for oral dosing and new pediatric formulations can be studied in TIMpediatric with a high predictive value.