Stability of Dexamethasone during Hot-Melt Extrusion of Filaments based on Eudragit® RS, Ethyl Cellulose and Polyethylene Oxide.

Hot-melt extrusion (HME) potentially coupled with 3D printing is a promising technique for the manufacturing of dosage forms such as drug-eluting implants which might even be individually adapted to patient-specific anatomy. However, these manufacturing methods involve the risk of thermal degradation of incorporated drugs during processing. In this work, the stability of the anti-inflammatory drug dexamethasone (DEX) was studied during HME using the polymers Eudragit® RS, ethyl cellulose and polyethylene oxide. The extrusion process was performed at different temperatures. Furthermore, the influence of accelerated screw speed, the addition of the plasticizers triethyl citrate and polyethylene glycol 6000 or the addition of the antioxidants butylated hydroxytoluene and tocopherol in two concentrations were studied. The DEX recovery was analyzed by a high performance liquid chromatography method suitable for the detection of thermal degradation products. The strongest impact on the drug stability was found for the processing temperature, which was found to reduce the DEX recovery to <20% for certain processing conditions. In addition, differences between tested polymers were observed, whereas the use of additives did not result in remarkable changes in drug stability. In conclusion, suitable extrusion parameters were identified for the processing of DEX with high drug recovery rates for the tested polymers. Moreover, the importance of a suitable analysis method for drug stability during HME that is influenced by several parameters was highlighted.

Impact of advanced age on the gastric emptying of water under fasted and fed state conditions.

Although older people are the main users of oral medications, few studies are reported on the influence of advanced age on gastric emptying rate of non-caloric liquids. This study aimed at evaluating the gastric emptying of 240 ml water in healthy older and young adults in fasted and fed state conditions using the established method of salivary caffeine kinetics. The gastric emptying of water was evaluated in 12 healthy older volunteers (mean age: 73 ± 6 years) and 12 healthy younger volunteers (mean age: 25 ± 2 years) with the ingestion of a rapid disintegrating tablet containing 20 mg of 13C3-caffeine. The gastric emptying of water was assessed indirectly by calculating the AUC ratios of salivary caffeine concentrations in specific time segments. Comparison of the AUC ratios showed no statistically significant difference between young and older volunteers in both fasted and fed state conditions (p > 0.05). Advanced age itself seems to have no relevant effect on gastric emptying of water in either fasted or fed state conditions and the phenomenon of Magenstrasse appears to follow a similar pattern in healthy older adults as in healthy younger adults.

Predicting gastric emptying of drug substances taken under postprandial conditions by combination of biorelevant dissolution and mechanistic in silico modeling.

Physiologically based pharmacokinetic (PBPK) models can help to understand the effects of gastric emptying on pharmacokinetics and in particular also provide a platform for understanding mechanisms of food effects, as well as extrapolation between different postprandial conditions, whether standardized clinical or patient-oriented, non-clinical conditions. By integrating biorelevant dissolution data from the GastroDuo dissolution model into a previously described mechanistic model of fed-state gastric emptying, we simulated the effects of a high-calorie high-fat meal on the pharmacokinetics of sildenafil, febuxostat, acetylsalicylic acid, theobromine and caffeine. The model was able to simulate the variability in Cmax and tmax caused by the presence of the stomach road. The main influences investigated to affect the gastric emptying process were drug solubility (theobromine and caffeine), tablet dissolution rate (acetylsalicylic acid) and sensitivity to gastric motility (sildenafil and febuxostat). Finally, we showed how PBPK models can be used to extrapolate pharmacokinetics between different prandial states using theobromine as an example with results from a clinical study being presented.

Prolongation of the gastric residence time of caffeine after administration in fed state: Comparison of effervescent granules with an extended release tablet.

The aim of the present study was to investigate the gastroretentive capacity of different formulation principles. This was indirectly determined by the absorption behavior of caffeine from the dosage forms. A slow and continuous appearance of caffeine in the saliva of healthy volunteers was used as a parameter for a prolonged gastric retention time. For this purpose, a four-way study was conducted with twelve healthy volunteers using the following test procedures: (1) Effervescent granules with 240 mL of still water administered in fed state, (2) effervescent granules with 20 mL of still water in fed state, (3) extended release (ER) tablet with 240 mL of still water in fed state, and (4) effervescent granules with 240 mL of still water in fasted state. The initial rise of the caffeine concentrations was more pronounced after the intake of the effervescent granules in the fed state compared to that of the ER tablets. However, tmax tended to be shorter in the fed study arms following administration of the ER tablet compared to the granules. Overall, the application of active pharmaceutical ingredients formulated as effervescent granules seems to be a promising approach to increase their gastric residence time after intake in fed state.

Investigation of real-life drug intake behaviour in older adults and geriatric patients in Northern Germany - A biopharmaceutical perspective.

Dosing conditions (type and amount of accompanying fluid, the type of food, the time of administration, and dosage form modifications such as crushing tablets) are critical and affect the performance of oral dosage forms in the gastrointestinal tract and thus bioavailability. Because older adults are the primary users of medications and are more susceptible to adverse effects, it is important to understand how they take their medications in order to reduce risks and increase benefits of the pharmacotherapy. The aim of the study was to investigate the real-life drug intake behaviour in geriatric patients and older adults and discuss their influence on drug absorption after oral administration. The data from two settings home vs. hospital and genders women vs. men were presented. A questionnaire study was performed among people aged at least 65 years from two settings (hospital vs. home), recruited mostly from community pharmacies and a regional hospital in Mecklenburg - Western Pomerania. The obtained data demonstrates that older adults and geriatric patients take their medications in the same way regardless of the setting and gender. There were no significant differences. Interviewed participants were mostly adherent to the doctor's recommendations and mostly took their medications in the same way every day. Medications are most commonly taken with a small (100 mL) or large (200 mL) glass of noncarbonated water, after food (during or after breakfast 64 % of intakes in the morning and during or after dinner 81 % of intakes in the evening). Meal usually consisted of bread, either with jam or honey (breakfast), or ham and cheese (dinner). All reported dosage form modifications were made to tablets. In almost all cases it was splitting the tablet, which was performed due to doctor's indication.

Determination of Gastric Water Emptying in Fasted and Fed State Conditions Using a Compression-Coated Tablet and Salivary Caffeine Kinetics.

Because of the importance of gastric emptying for pharmacokinetics, numerous methods have been developed for its determination. One of the methods is the salivary tracer technique, which utilizes an ice capsule containing caffeine as a salivary tracer. Despite the ice capsule's advantage in labeling ingested fluids with caffeine for subsequent salivary detection, its risk of premature melting before swallowing, and its complicated storage and preparation, limit its application, particularly in special populations (e.g., older people). For this reason, here, a compression-coated tablet was developed and validated against the ice capsule in a cross-over clinical trial. The two dosage forms were administered simultaneously to 12 volunteers in an upright position under fasted and fed state conditions. To distinguish the caffeine concentrations in saliva from each dosage form, regular type of caffeine (12C) was added to the tablet, while for the ice capsule 13C3 labelled caffeine was used. The salivary caffeine concentrations showed no statistically significant differences for the pharmacokinetic parameters tmax and AUC0→60 (p > 0.05). Thus, the new formulation is a useful tool for determining gastric emptying that can also be used in special populations.

Influence of Different Diets on the Degradation of Sulfasalazine by Colon Bacteria Determined Using MimiCol3.

The microbiome of the colon is characterized by its great diversity. This varies not only intra- but also interindividually and is influenced by endogenous and exogenous factors, such as dietary and lifestyle factors. The aim of this work was to investigate the extent to which the degradation of the drug sulfasalazine is influenced by different microbiota. Therefore, the in vitro model MimiCol3 was used, which represents the physiological conditions of the ascending colon. In addition to a representative physiological volume, the pH value, redox potential and an anaerobic atmosphere are important to provide the bacteria with the best possible growth conditions. Stool samples were taken from three healthy subjects, comparing omnivorous, vegetarian and meat-rich diets, and cultured for 24 h. However, the nutrient medium used for cultivation led to the alignment of the bacterial composition of the microbiota. The previously observed differences between the diets could not be maintained. Nevertheless, the similar degradation of sulfasalazine was observed in all microbiota studied in MimiCol3. This makes MimiCol3 a suitable in vitro model for metabolism studies in the gut microbiome.

High-Dose Spermidine Supplementation Does Not Increase Spermidine Levels in Blood Plasma and Saliva of Healthy Adults: A Randomized Placebo-Controlled Pharmacokinetic and Metabolomic Study.

(1) Background: Spermidine is a biogenic polyamine that plays a crucial role in mammalian metabolism. As spermidine levels decline with age, spermidine supplementation is suggested to prevent or delay age-related diseases. However, valid pharmacokinetic data regarding spermidine remains lacking. Therefore, for the first time, the present study investigated the pharmacokinetics of oral spermidine supplementation. (2) Methods: This study was designed as a randomized, placebo-controlled, triple-blinded, two-armed crossover trial with two 5-day intervention phases separated by a washout phase of 9 days. In 12 healthy volunteers, 15 mg/d of spermidine was administered orally, and blood and saliva samples were taken. Spermidine, spermine, and putrescine were quantified by liquid chromatography-mass spectrometry (LC-MS/MS). The plasma metabolome was investigated using nuclear magnetic resonance (NMR) metabolomics. (3) Results: Compared with a placebo, spermidine supplementation significantly increased spermine levels in the plasma, but it did not affect spermidine or putrescine levels. No effect on salivary polyamine concentrations was observed. (4) Conclusions: This study's results suggest that dietary spermidine is presystemically converted into spermine, which then enters systemic circulation. Presumably, the in vitro and clinical effects of spermidine are at least in part attributable to its metabolite, spermine. It is rather unlikely that spermidine supplements with doses <15 mg/d exert any short-term effects.

Intragastric Carbon Dioxide Release Prolongs the Gastric Residence Time of Postprandially Administered Caffeine.

Sparkling water is said to increase gastric motility by the release of carbon dioxide, thereby potentially affecting the pharmacokinetics of orally administered drugs. The hypothesis of the present work was that the induction of gastric motility by intragastric release of carbon dioxide from effervescent granules could promote the mixing of drugs into the chyme under postprandial conditions, resulting in a prolonged drug absorption. For this purpose, an effervescent and a non-effervescent granule formulation of caffeine as a marker for gastric emptying were developed. In a three-way crossover study with twelve healthy volunteers, the salivary caffeine pharmacokinetics, after administration of the effervescent granules with still water and the administration of the non-effervescent granules with still and sparkling water, were investigated after intake of a standard meal. While the administration of the effervescent granules with 240 mL of still water led to a significantly prolonged gastric residence of the substance compared to the administration of the non-effervescent granules with 240 mL still water, the application of the non-effervescent granules with 240 mL sparkling water did not prolong gastric residence via mixing into caloric chyme. Overall, the mixing of caffeine into the chyme following the administration of the effervescent granules did not seem to be a motility mediated process.

Bridging the Gap between Food Effects under Clinical Trial Conditions and Real Life: Modeling Delayed Gastric Emptying of Drug Substances and Gastric Content Volume Based on Meal Characteristics.

Delayed gastric emptying is known to have a major impact on drug absorption. While the test meal recommended by the FDA and EMA to study food effects represents a worst-case scenario, it does not reflect the reality of the patients. Physiologically based pharmacokinetic (PBPK) models could bridge the gap between clinical settings of food effect studies and the diverse nonclinical situations by simulating the effect of meals with different compositions and volumes. A mathematical equation based on a stretched exponential function was reparameterized to describe the gastric emptying process of mixed solid meals. The model was fitted to literature data including the gastric emptying data of 23 meals from 15 studies. Using a multiple linear regression model, we were able to predict the two function parameters from the meal characteristics caloric content and the percentage of calories derived from fat. After implementation into the PBPK software PK-Sim, the model, together with a separate compartment for liquid gastric contents, was compared to commercially available software. The model is able to simulate the gastric emptying of mixed solid meals containing drugs based on specific meal characteristics. A second compartment allows for distribution between liquid and solid components and rapid gastric emptying along the Magenstrasse.

An Advanced Bioreactor Simulating Dynamic Physiological Conditions in the Human Ascending Colon: MimiCol3.

In recent years, the colon has become a hot topic in biopharmaceutical research as several in vitro models of the human colon have been presented. A major focus is on the characterization of the microbiota and its capabilities. The aim of the present study was to further develop the MimiCol, preserving its properties and accelerating data acquisition. Emphasis was placed on the simplicity of its design and easy scalability. To prove the viability of the concept, degradation of sulfasalazine was investigated, and the bacterial composition during the experiment was assessed by 16S rRNA sequencing. The transfer of the experimental conditions to the new model was successful. Commercially available components were implemented in the setup. The model MimiCol3 represented the colon ascendens satisfactorily in its properties regarding volume, pH value, and redox potential. 16S rRNA sequencing led to further insights into the bacterial composition in the vessels. Degradation of sulfasalazine was in good agreement with in vivo data. The new model of the colon ascendens MimiCol3 enabled us to collect more reliable data, as three experiments were conducted simultaneously under the same conditions.

Application of In Vivo Imaging Techniques and Diagnostic Tools in Oral Drug Delivery Research.

Drug absorption following oral administration is determined by complex and dynamic interactions between gastrointestinal (GI) physiology, the drug, and its formulation. Since many of these interactions are not fully understood, the COST action on "Understanding Gastrointestinal Absorption-related Processes (UNGAP)" was initiated in 2017, with the aim to improve the current comprehension of intestinal drug absorption and foster future developments in this field. In this regard, in vivo techniques used for the characterization of human GI physiology and the intraluminal behavior of orally administered dosage forms in the GI tract are fundamental to gaining deeper mechanistic understanding of the interplay between human GI physiology and drug product performance. In this review, the potential applications, advantages, and limitations of the most important in vivo techniques relevant to oral biopharmaceutics are presented from the perspectives of different research fields.

Integration of advanced methods and models to study drug absorption and related processes: An UNGAP perspective.

This collection of contributions from the European Network on Understanding Gastrointestinal Absorption-related Processes (UNGAP) community assembly aims to provide information on some of the current and newer methods employed to study the behaviour of medicines. It is the product of interactions in the immediate pre-Covid period when UNGAP members were able to meet and set up workshops and to discuss progress across the disciplines. UNGAP activities are divided into work packages that cover special treatment populations, absorption processes in different regions of the gut, the development of advanced formulations and the integration of food and pharmaceutical scientists in the food-drug interface. This involves both new and established technical approaches in which we have attempted to define best practice and highlight areas where further research is needed. Over the last months we have been able to reflect on some of the key innovative approaches which we were tasked with mapping, including theoretical, in silico, in vitro, in vivo and ex vivo, preclinical and clinical approaches. This is the product of some of us in a snapshot of where UNGAP has travelled and what aspects of innovative technologies are important. It is not a comprehensive review of all methods used in research to study drug dissolution and absorption, but provides an ample panorama of current and advanced methods generally and potentially useful in this area. This collection starts from a consideration of advances in a priori approaches: an understanding of the molecular properties of the compound to predict biological characteristics relevant to absorption. The next four sections discuss a major activity in the UNGAP initiative, the pursuit of more representative conditions to study lumenal dissolution of drug formulations developed independently by academic teams. They are important because they illustrate examples of in vitro simulation systems that have begun to provide a useful understanding of formulation behaviour in the upper GI tract for industry. The Leuven team highlights the importance of the physiology of the digestive tract, as they describe the relevance of gastric and intestinal fluids on the behaviour of drugs along the tract. This provides the introduction to microdosing as an early tool to study drug disposition. Microdosing in oncology is starting to use gamma-emitting tracers, which provides a link through SPECT to the next section on nuclear medicine. The last two papers link the modelling approaches used by the pharmaceutical industry, in silico to Pop-PK linking to Darwich and Aarons, who provide discussion on pharmacometric modelling, completing the loop of molecule to man.

Mimicking the dynamic Colonic microbiota in vitro to gain a better understanding on the in vivo metabolism of xenobiotics: Degradation of sulfasalazine.

Due to the potential effects of colonic metabolism, the interest in the composition and action of intestinal microbiota has increased significantly throughout the last 10 years. Recently focus is turning to the development and implementation of in vitro tools closely simulating in vivo colonic metabolic processes suitable for routine use. The aim of the present study is to compare the metabolization of the model drug sulfasalazine utilizing the novel dynamic bioreactor MimiCol and a standard static batch fermenter inoculated with cryopreserved faecal microbiota. Major advantages of the novel bioreactor MimiCol are the smaller media volume which is closer to in vivo conditions, the possibility to perform media changes and the closer simulation of in vivo mixing patterns. The study proved that the MimiCol is able to simulate the dynamic conditions found within the ascending colon. The dynamic conditions within the MimiCol led to an almost 2-fold increase of the metabolization rate constant in comparison to the static batch fermenter. Our study was able to prove that the novel dynamic bioreactor MimiCol is able to closely simulate physiologically relevant conditions.

Design and Optimization of a Novel Strategy for the Local Treatment of Helicobacter pylori Infections.

Infections with Helicobacter pylori are a global challenge. Currently, H. pylori infections are treated systemically, but the eradication rates of the different therapy regimens are declining due to the growing number of bacterial strains resistant to major antibiotics. Here, we present a strategy for the local eradication of H. pylori by the use of Penicillin G sodium (PGS). In vitro experiments revealed that PGS shows high antibiotic activity against resistant strains of Helicobacter pylori with a minimum inhibitory concentration (MIC) of 0.125 µg/ml. In order to provide luminal concentrations above the MIC for longer periods of time, an extended release tablet was developed. Alkalizers were included to prevent acidic degradation of PGS within the tablet matrix. Out of the tested alkalizers MgO, l-Lysine, NaHCO3, and Na2CO3 NaHCO3 provided the strongest rise in pH inside the hydrated matrix when tested in simulated gastric fluid. Better PGS stability can mainly reasoned from that, addition of MgO resulted in high pH values within the matrix, causing basic degradation of PGS. This work is a first step towards the use of extended release tablets containing PGS for the local treatment of H. pylori as a safe and cost-effective alternative to common systemic treatment regimens.

Application of the GastroDuo to study the interplay of drug release and gastric emptying in case of immediate release Aspirin formulations.

The process of gastric emptying is of major importance for the in vivo performance of immediate release dosage forms. In the fed state, this process consists of two phases: the rapid emptying of water along the "Magenstrasse" and the continuous emptying of the chyme. The relevance of these phases for the pharmacokinetic (PK) profile of a drug depends on the release behavior from its dosage form. It was the aim of this study to investigate the role of gastric emptying for the pharmacokinetics of a fast disintegrating and dissolving Aspirin® tablet (FDDT). For this purpose, a three way pharmacokinetic study with 30 healthy volunteers was performed to investigate the performance of the FDDT under fasted and fed conditions and compare it to a regular Aspirin® tablet (RT) administered in the fed state. Plasma samples were taken at predetermined time points and analyzed by LC MS/MS. In the second part of this work, both products were tested in a biorelevant dissolution test device - the GastroDuo. To simulate the occurrence of the Magenstrasse at different time points, two test programs have been applied. The results of the PK study clearly demonstrated the superiority of the FDDT over the RT. We observed an earlier tmax (0.39 h vs. 2.00 h) and a higher Cmax (6.33 ± 2.37 µg/mL vs. 3.23 ± 1.28 µg/mL), whereas the AUC was only slightly different between both formulations. The administration of the FDDT together with food had no marked effect on tmax (0.34 h vs. 0.39 h), but caused a decrease in Cmax compared to fasted intake (14.76 ± 4.81 µg/mL vs. 6.33 ± 2.37 µg/mL). This effect could be explained by the in vitro data collected with the GastroDuo. The FDDT showed a faster drug release and improved emptying kinetics in the GastroDuo. In contrast, the RT showed incomplete emptying in both test programs. Thus, the early tmax observed for the FDDT under fed conditions could be related to the presence of the Magenstrasse. In contrast, drug release from the RT was insufficient to allow gastric emptying via the Magenstrasse, which resulted in later tmax. This study highlighted the importance of gastric emptying for immediate release dosage forms and illustrated that the application of suitable formulation techniques provides a strategy to generate a fast and reliable onset of drug plasma concentrations even in the fed state.

Comparison of In Vitro and In Vivo Results Using the GastroDuo and the Salivary Tracer Technique: Immediate Release Dosage Forms under Fasting Conditions.

The fasted state administration of immediate release (IR) dosage forms is often regarded as uncritical since physiological aspects seem to play a minor role for disintegration and drug release. However, recent in vivo studies in humans have highlighted that fasted state conditions are in fact highly dynamic. It was therefore the aim of this study to investigate the disintegration and drug release behavior of four different IR formulations of the probe drug caffeine under physiologically relevant conditions with the aid of the GastroDuo. One film-coated tablet and three different capsule formulations based on capsule shells either made from hard gelatin or hydroxypropylmethyl cellulose (HPMC) were tested in six different test programs. To evaluate the relevance of the data generated, the four IR formulations were also studied in a four-way cross-over study in 14 healthy volunteers by using the salivary tracer technique (STT). It could be shown that the IR formulations behaved differently in the in vitro test programs. Thereby, the simulated parameters affected the disintegration and dissolution behavior of the four IR formulations in different ways. Whereas drug release from the tablet started early and was barely affected by temperature, pH or motility, the different capsule formulations showed a longer lag time and were sensitive to specific parameters. However, once drug release was initiated, it typically progressed with a higher rate for the capsules compared to the tablet. Interestingly, the results obtained with the STT were not always in line with the in vitro data. This observation was due to the fact that the probability of the different test programs was not equal and that certain scenarios were rather unlikely to occur under the controlled and standardized conditions of clinical studies. Nonetheless, the in vitro data are still valuable as they allowed to discriminate between different formulations.

Application of the GastroDuo as an in Vitro Dissolution Tool To Simulate the Gastric Emptying of the Postprandial Stomach.

In the postprandial stomach, processes such as secretion, digestion, and gastric emptying all occur simultaneously. Therefore, the system is highly heterogeneous and dynamically changing, for instance, in terms of various physicochemical parameters such as pH value or viscosity. Thus, the administration of a drug together with food can result in highly variable drug plasma concentrations, which may affect the efficacy and safety of the pharmacotherapy. In this work, the pharmacokinetic (PK) data obtained from two fed-state bioequivalence studies with the immediate release (IR) drug products Viagra (sildenafil) and Adenuric (febuxostat) have been analyzed. This evaluation revealed that basically three characteristic types of onset behaviors of drug plasma concentration can be distinguished. It was hypothesized that the different types of onset behaviors were mainly caused by the interplay between gastric drug dissolution and gastric emptying. To study this interplay in vitro, a biopredictive dissolution tool-GastroDuo-was developed and used for both drug products. Therefore, three different test programs have been applied to simulate certain aspects of the postprandial human stomach, which included dynamic pH changes, gastric peristalsis, and the kinetics of gastric emptying. Specifically, the behavior of noncaloric fluids by the so-called "Magenstrasse" was taken into deeper consideration. The experiments revealed that the dissolution and emptying behavior of the two drug products were affected in different ways by the three test programs. The in vitro data nicely explained the tendencies of the drug products for certain types of onset behaviors observed in the PK data. While Viagra was strongly affected by simulated peristalsis, Adenuric was more sensitive to the simulated emptying kinetics. This work clearly demonstrated the important role of gastric fluid emptying for the onset of drug plasma concentration after oral administration of IR formulations in the fed state. Moreover, this was the first study in which GastroDuo was applied as a biopredictive in vitro model which is able to simulate crucial parameters of the human stomach (e.g., pH profiles and gastric emptying) in a realistic manner.

In vivo characterization of enTRinsic™ drug delivery technology capsule after intake in fed state: A cross-validation approach using salivary tracer technique in comparison to MRI.

The instability of various small molecules, vaccines and peptides in the human stomach is a complex challenge for oral drug delivery. Recently, a novel gastro-resistant capsule - the enTRinsic™ Drug Delivery Technology capsule - has been developed. In this work, the salivary tracer technique based on caffeine has been applied to study the in vivo disintegration of enTRinsic™ capsules in 16 healthy volunteers. In addition, magnetic resonance imaging (MRI) was used to visualize GI transit and to verify the disintegration times determined by using the salivary tracer technique. The enTRinsic™ capsules filled with 50mg of caffeine and 5mg of black iron oxide were administered in the fed state, i.e. 30min after a light meal (500kcal). In the first hour after capsule intake, the subjects were placed in supine position in the MRI scanner and scans were performed in short time intervals. After 1h, the subjects could leave the MRI scanner in between the MRI measurements, which were performed every 15min until disintegration of the capsule was confirmed (maximum observation time: 8h). Saliva samples were obtained simultaneously with MR imaging. Caffeine concentrations in saliva were determined by LC/MS-MS. The starting point of capsule disintegration was determined visually by inspection of the MR images as well as by the onset of salivary caffeine concentrations. In 14 out of 16 subjects, the capsule disintegrated in the small intestine. In one subject, the enTRinsic™ capsule was not emptied from the stomach within the observation time. In another subject, disintegration occurred during gastric emptying in the antropyloric region. In this study, we demonstrated that the enTRinsic™ capsules are also gastro resistant when taken under fed state conditions. Furthermore, we demonstrated the feasibility of using low dose caffeine as a salivary tracer for the determination of the disintegration of an enteric formulation.