PHARMACEUTICAL ORAL DOSAGE FORMS FOR TREATMENT OF METABOLIC DISORDERS AND RELATED DISEASES THROUGH ORCHESTRATED RELEASE OF ENTEROKINES

Abstract

The present invention relates to pharmaceutical oral dosage forms releasing compounds in specific parts of the small intestine of a subject, wherein said compounds stimulate enteroendocrine cells in the subject's jejunum and lower small intestine to release one or more enterokines. The present invention also relates to a method of producing such pharmaceutical oral dosage forms. The pharmaceutical oral dosage forms of the invention are particularly for use in the treatment and prevention of metabolic conditions or diseases, osteoporosis, malabsorption conditions, neurodegenerative diseases, conditions of impaired gastro-intestinal function and cardiovascular diseases.

Claims

1. A pharmaceutical oral dosage form comprising a core and a pH-sensitive enteric coating, wherein the core comprises at least one compound stimulating enteroendocrine cells to release at least one enterokine, and at least one disintegrant providing a burst release of the ingredients of the core when the coating is substantially degraded or dissolved, and wherein the coating is a pH sensitive polymer that substantially dissolves or is substantially degraded in the jejunum of a subject.

2. The oral dosage form of claim 1 wherein the at least one compound is selected from the group consisting of compounds stimulating the enteroendocrine cells by a mechanism selected from the group consisting of transport into enteroendocrine cells by a transporter expressed by said cells wherein the transporter is selected from the group consisting of GLUT2 and SGLT1, and binding to G protein-coupled receptors expressed by said cells.

3. The oral dosage form of claim 2 wherein the G-protein-coupled receptor is selected from bile acid receptors, amino acid receptors, peptide receptors and fatty acid receptors and taste receptors.

4. The oral dosage form of claim 2 wherein said at least one compound is selected from the group consisting of carbohydrates, fatty acids, bile acids, peptides, amino acids, alcohol amides, and anthocyanins.

5. The oral dosage form of claim 4 wherein the core contains glucose, and optionally one or more compounds selected from sucralose, fatty acids having 2 to 6 carbon atoms, oleic acid, bile acids, peptides, amino acids, ethanolamides and anthocyanins.

6. The oral dosage form of claim 4 wherein the anthocyanin is delphinidin 3-rutinoside.

7. The oral dosage form according to claim 1 wherein the enteroendocrine cells are selected from the group consisting of I cells, K cells and L cells.

8. The oral dosage form according to claim 1 wherein the core further contains an enteroendocrine cell maturation agent.

9. The oral dosage form of claim 8 wherein the maturation agent is a human milk oligosaccharide (HMO).

10. The oral dosage form according to claim 1 wherein the pH sensitive polymer substantially degrades and/or dissolves at a pH value of about 5.5 to about 7.5, preferably about 7.2 to about 7.3.

11. The oral dosage form according to claim 1 wherein the pH sensitive polymer is selected from the group consisting of hydroxypropylmethyl celluloses and anionic copolymers of methacrylic acid and methacrylmethacrylate.

12. The oral dosage form of claim 11 wherein the hydroxypropylmethyl cellulose is hydroxypropylmethyl cellulose acetate succinate.

13. (canceled)

14. The oral dosage form according to claim 11, wherein the coating comprises a first layer and a second layer of a pH sensitive polymer, the second layer being coated onto the first layer.

15. The oral dosage form of claim 14 wherein the first layer contains or is made of an anionic copolymer of methacrylic acid and methacrylmethacrylate.

16. The oral dosage form of claim 15 wherein the second layer contains or is made of hydroxypropylmethyl cellulose.

17. The oral dosage form according to claim 14 wherein the ratio of thickness between the first and the second layer is from about 1:10 to about 1:50.

18. The oral dosage form according to claim 1 wherein the disintegrant is selected from the group consisting of a crosslinked polyvinylpyrrolidone, a crosslinked carboxymethyl cellulose and a modified starch.

19. The oral dosage form of claim 18 wherein the crosslinked polyvinylpyrrolidone is Polyplasdone.

20. amended) The oral dosage form according to claim 1 wherein the enterokine selected from the group consisting of GLP-1, PYY, GLP-2, CCK, GIP and neurotensin, preferably GLP-1 and PYY.

21. The oral dosage form according to claim 1 wherein the core further comprises a tracer substance.

22. The oral dosage form of claim 21 wherein the tracer substance is caffeine.

23. The oral dosage form of claim 22 wherein the core contains 60 to 70% (w/w) glucose and 2 to 4% (w/w) caffeine, based on the total weight of the core.

24. The oral dosage form of claim 23 wherein the core contains 67% (w/w) glucose and 3.2% (w/w) caffeine, based on the total weight of the core.

25. The oral dosage form according to claim 1 where the oral dosage form is the form of a tablet, capsule, pellet or granule.

26. The oral dosage form according to claim 25 having a size of less than 3 mm, based on the largest dimension of the oral dosage form.

27. The oral dosage form of claim 26 wherein the size is from about 0.6 mm to about 1.7 mm, based on the largest dimension of the oral dosage form.

28. A pharmaceutical oral dosage form according to claim 1 for use in the prevention and/or treatment of a condition or disease selected from the group consisting of insulin resistance, type 2 diabetes mellitus, non-alcoholic fatty liver disease, non-alcoholic steatohepatosis, microvascular dysfunction, metabolic syndrome, obesity, cardiovascular diseases, osteoporosis, neurodegenerative diseases, impaired gastro-intestinal function and malabsorption conditions in a subject.

29. The pharmaceutical oral dosage form for the use of claim 28 wherein said dosage form is formulated such that the at least one compound stimulating enteroendocrine cells to release an enterokine stimulates said cells present in the intestine of the subject from the jejunum to the ileo-cecal valve of the subject.

30. A method for preparing a pharmaceutical oral dosage form comprising the steps of: (a) preparing a mixture comprising at least one compound stimulating enteroendocrine cells to release at least one enterokine, and at least one disintegrant; (b) compressing the mixture obtained in step (a); and (c) applying to the compressed mixture at least one coating comprising at least one pH sensitive polymer which substantially degrades and/or dissolves at a pH value of about 5.5 to about 7.5.

31. Pharmaceutical oral dosage forms comprising a core and a pH-sensitive enteric coating, wherein the core comprises at least one nutrient compound stimulating enteroendocrine cells to release at least one enterokine, and at least one disintegrant providing a burst release of the ingredients of the core when the coating is substantially degraded and/or dissolved, and wherein the coating comprises a pH sensitive polymer which substantially degrades and/or dissolves at a pH value of about 5.5 to about 7.5, wherein the dosage forms have a size of less than 3 mm, based on the largest dimension of the oral dosage forms, and release said nutrient compound in the terminal jejunum of a subject.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0060] FIG. 1: illustrates GLP-1 and PYY release by L cells along the small intestine. The left panel is a schematic representation of the gastro-intestinal tract of a human. The human's small intestine comprises, from gastric side to colon side, the three parts duodenum, jejunum and ileum. L cells are present in the human small intestine from duodenum to ileum with the concentration and maturation of L cells increasing from proximal to distal small intestine. The highest concentration of L cells is found in the terminal (i.e. distal) ileum. Panels on the right show the time dependency of GLP-1 and PYY, respectively, output of L cells in the jejunum (upper right panel) and in the ileum (lower right panel). Upon stimulation by nutrients, here exemplified by glucose, L cells release the enterokines GLP-1 and PYY, whereby GLP-1 is released from L cells throughout the small intestine (i.e. duodenum, jejunum and ileum), however, substantial release of GLP-1 starts in the jejunum and increases from proximal to distal small intestine with peak release in the terminal ileum. On the contrary, PYY release is much lower in the jejunum and increases strongly only in the ileum where GLP-1 and PYY are co-released to substantially equal extend.

[0061] FIG. 2: illustrates the improved effect on release of GLP-1 and PYY through the burst release of the enterokine-stimulating content of the pharmaceutical oral dosage forms of the invention in the jejunum, preferably the terminal jejunum. The oral dosage form of the invention specifically releases its core contents in the jejunum of the, preferably human, subject, in a timely sharp manner so that an abrupt bolus of the enterokine-stimulating substance rapidly develops. The enterokine-stimulating substance travels from jejunum to ileum and through ileum making sure that an as large as possible population of L cells is stimulated to release GLP-1 (in the jejunum) and GLP-1 and PYY (in the ileum). In this manner, the pharmaceutical oral dosage form of the invention provides that the at least one compound stimulating enteroendocrine cells to release an enterokine stimulates said cells present in the intestine of the subject from the jejunum to the ileo-cecal valve of the, preferably human, subject. Thus, the strategy according to the invention optimises GLP-1 and PYY release from L cells per unit dose such that the overall dose (per dosage administered and overall dose per time interval such as per day) can be kept low in comparison to prior art approaches.

[0062] FIG. 3: shows a schematic representation of a cross-section of a villus in the mucosa of the small intestine of a human subject. GLP-1 is released from L cells in the crypts and on the villi. However, the GLP-1 release capacity per L cells increases with the maturation state of the L cell, i.e. it is highest when the L cells reach the top of the villi. Contrary to GLP-1, L cells start to synthesize PYY only at a higher maturation state. The maturation of L cells can be accelerated by substances such as human milk oligosaccharides (HMO) and a variety of pathway inhibitors (e.g. NOTCH signalling inhibitors). Thus, combining L cell maturation enhancing substances with a nutrient or like glucose or other active compound (such as anthocyanin) in the inventive oral dosage forms leads to a synergistic increase of GLP-1 and PYY by L cells.

[0063] FIG. 4: is a schematic representation showing the various molecular mechanisms by which a stimulus to an L cell is translated in the cell to a release of enterokines GLP-1 and PYY. Thus, GLP-1 and PYY are released in response to stimuli that activate glucose transporters (GLUT2, SGLT1) and G protein-coupled receptors such as taste receptors, fatty acid receptors, amino acid receptors and bile acid receptors. The signals generated by the glucose transporters or G-protein-coupled receptors are transmitted by three main mechanisms: transmembrane calcium influx, intracellular calcium release and intracellular cAMP release. Hence, signalling events in L cells can be separated into three segments: (i) glucose transporter (GLUT2 and SGTL1) levels and levels of G protein-coupled receptors; (ii) the intracellular signalling pathway level (calcium and cAMP-dependent pathways); and (iii) the amount of fusion events of vesicles with the plasma membrane to release their content (release level). Through these mechanisms the nature of the released enterokine does not depend on the stimulus or signalling pathways involved but exclusively on (a) the location of the L cell in the small intestine (duodenum, jejunum or ileum) and (b) on the maturation state of the L cell (corresponding to its position in the crypts or on the villi of the mucosa).

[0064] FIG. 5: shows a graphic representation depicting the data of online UVNIS spectrophotometric measurement of caffeine released from the core of a pharmaceutical oral dosage form of the invention in an aqueous buffer as indicated over time. The data show a burst release of the core components: almost 70% of the core contents are released into the buffer solution within less than 2 min, and more than 85% are released within 5 min.

[0065] FIG. 6: illustrates the impact of the dimensions of the inventive pharmaceutical dosage form on its behaviour in the gastrointestinal tract: larger oral dosage forms (e.g. tablets, capsules) having a largest dimension of 3 mm or more (upper encircled area in the middle diagram) behave like solid food as regards the rate of gastric emptying. Such larger oral dosage forms show a lag phase after ingestion, slow gastric emptying, they travel slow through the small intestine, and are fractionated into separate boli (in the case of multiple tablets or capsules and the like, fractionation of the overall orally administered dose) through periodic pyloric sphincter opening. On the contrary, small oral dosage forms of less than 3 mm in their largest dimension behave like fluids (lower encircled area in the middle diagram). They show no lag phase in gastric emptying which follows instantaneously after ingestion. Consequently, such small oral dosage forms travel much faster through the small intestine as compared to dosage forms having 3 mm or more in their largest dimension, and exhibit only a limited fractionation of the overall dose administered.

[0066] FIG. 7: shows graphical representations of experimental data obtained from GLUTag cells (as a cell culture model of human L cells, especially in terms of their stimulation properties to secrete enterokines; cf. Kuhre et al. (2016) J. Mol. Endocrinol. 56 (3), 201-211) stimulated by the indicated active compounds at the indicated concentrations (depolarization and the mixture of Forskolin (3R,4aR,5S,6S,6aS,10S,10aR,10bS)-dodecahydro-5,6,10,10b-tetrahydroxy-3,4a,7,7,10a-pentamethyl-1-oxo-3-vinyl-1H-naphtho[2,1-b]pyran-5-yl acetat)/BMK (the venom of scorpion Buthus martensii Karsch) were used as positive controls). GLP-1 release was measured in the stimulation medium supernatant. (A) Data of GLP-1 release are expressed as fold increase in comparison to negative control (stimulation medium supernatant of cells without treatment by any stimulus) (B) Data of GLP-1 release are expressed as GLP-1 concentration in the stimulation medium supernatant with signal of negative control (stimulation medium supernatant of cells without treatment by any stimulus) subtracted. Numbers in brackets above the columns indicate the number of independent experiment for each stimulant or control, respectively.

[0067] FIG. 8: shows graphical representations of dose response data of GLUTag cells stimulated with glucose (FIG. 8A), ethanolamide (FIG. 8B) or delphinidin 3-rutinoside (FIG. 8C) at the indicated concentrations.

[0068] FIG. 9: shows a graphical representation of experimental data obtained from GLUTag cells (as a cell culture model of L cells) stimulated by BSA at 0.5% (w/v). GLP-1 concentration was measured in the stimulation medium supernatant. The phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (IBMX) was used as positive control. Negative control was stimulation medium supernatant only.

[0069] FIG. 10: shows a graphical representation of experimental in vivo data of caffeine concentrations in blood serum taken before and at the indicated time points after ingestion of a pharmaceutical oral dosage form of the invention corresponding to 125 mg glucose administered orally to a volunteer after overnight fasting. The data show a sharp increase of caffeine concentration from 3 to 4 hours post administration of the pharmaceutical oral dosage form. The data confirm the burst release behaviour of the pharmaceutical oral dosage form of the invention. The onset of the peak interval at 3 hours post administration indicates that the release occurs in the terminal jejunum of the volunteer; cf. also FIG. 13.

[0070] FIG. 11: shows a graphical representation of experimental in vivo data of GLP-1 concentrations in blood serum taken as described above for FIG. 10. From a GLP-1 baseline concentration of 5 pmol/1 measured before administration of the pharmaceutical oral dosage form of the invention administered in a total dose of 125 mg glucose, the GLP-1 concentration doubles from 3 to 4 hours post administration, and reaches a plateau concentration of almost 15 pmol/1 serum.

[0071] FIG. 12: shows an overlay of the data of FIG. 10 (caffeine serum concentration) and FIG. 11 (GLP-1 serum concentration) indicating that sharp increase in GLP-1 concentration matches the burst release of the components from the core of the pharmaceutical oral dosage form of the invention.

[0072] FIG. 13: shows a further overlay of the caffeine and GLP-1 concentration, respectively, according to FIG. 12, but showing also the time post administration which corresponds to a localization of the pharmaceutical oral dosage from in the jejunum and ileum, respectively (indicated below the horizontal axis), according to known data of travelling times of typical pharmaceutical oral dosage forms as exemplified by a pH-sensitive and radiotelemetry capsule disclosed in Evans et al. (1988).

[0073] FIG. 14: shows a graphical representation of data of travelling time, localization and measured pH of a pH sensitive radiotelemetry capsule as measured by Evans et al. (1988) Gut 29, 1035-1041. The Fig. is a reproduction of FIG. 3 of Evans et al. (1988), page 1038.

DETAILED DESCRIPTION OF THE INVENTION

[0074] The following non-limiting examples further illustrate the present invention.

EXAMPLES

Example 1

Burst Release Tablet Core

[0075] A core for a pharmaceutical oral dosage form of the invention has been developed to provide a burst release kinetic of disintegration in tap water or aqueous buffer of less than 2 min. Glucose has been selected as an example of the active compound.

[0076] A glucose gentle direct compression process was used employing specific functional excipients to enable a good followability as well as processability and tablet properties on the one hand side and a fast disintegration and dissolution behaviour of glucose on the other hand. More specifically, the following excipients were selected: [0077] Silicified microcrystalline cellulose (Prosolv SMCC 90) has been selected and [0078] utilized as a binder. [0079] Crossinked povidone—Crospovidone (Polyplasdone XL-10) has been selected as super-disintegrant to provide a burst release kinetic. [0080] Magnesium stearate and colloidal silicon dioxide (Aerosil 200) have been selected as lubricant and glidant agents, respectively.

[0081] The final composition of the tablet core is given in Table 1

TABLE-US-00001 TABLE 1 Composition of the glucose tablet core Compound Function Concentration [% (w/w)] Glucose anhydrous Active Pharmaceutical 60.0 Ingredient (API) Caffeine Internal standard 1.4 Polyplasonde XL-10 Disintegrant 5.0 Magnestium stearate Lubricant 1.0 Aerosil 200 Glidant 0.2 Prosolv SMCC 90 Binder 32.4 Sum 100.0 [0082] The prepared oral dosage form showed the following general characteristics: [0083] Weight: 1.67+/−1.2% [0084] Height: 8.3 mm+/−0.4% [0085] Breaking strength: 245 N+/−7% [0086] Disintegration: <30 s

[0087] The burst release of the tablet core in aqueous buffer (500 ml 0.05 M phosphate buffer, pH 7.3 at 37° C.) was measured by online UV/VIS spectrophotometry of the caffeine as internal standard. The results of two independent experiments are shown in FIG. 5. The results show a fast dissolution of about >85% release of the internal standard within 5 min.

Example 2

Hypromellose Acetate Succinate-Coated Tablet

[0088] The tablet core of Example 1 was coated with AQOAT®-HF to provide an enteric coating and drug please at a specific pH value of >6.8, specifically at pH 7.3. In more detail, the tablet core of Example 1 was spray-coated using the following coating composition:

TABLE-US-00002 TABLE 2 AQOAT ® coating composition Compound Function Concentration [% (w/w)] Water Dispersant 91.9 Triethyl citrate (TEC) Plasticizer 1.7 Sodium lauryl sulfate (SLS) Wetting agent 0.3 Talcum Anti-tacking agent 1.4 AQOAT ® AS-HF pH sensitive polymer 4.7 Sum 100.0
The above coating was applied on the tablet core of Example 1 by using a LCH 25 Lödige lab-coater (Gebruder Lödige Maschinenbau GmbH, Paderborn, Germany).

Example 3

Eudragit®-Coated Tablet

[0089] In an alternative embodiment of the invention, the tablet core of Example 1 was coated with Eudragit® FS30D to provide an enteric coating and drug release at a pH value of >7.0, specifically at pH 7.3. In more detail, the tablet core of Example 1 was spray-coated using the following coating composition:

TABLE-US-00003 TABLE 3 Eudragite ®coating composition Compound Function Concentration [% (w/w)] Water Dispersant 80.0 Plasacryl (CMS TEC Anti-tacking, plasticizer, 1.8 Polysorbate 80) wetting agent Eudragite ® FS3OD pH-sensitive polymer 18.2 Sum 100.0
The above coating was applied on the tablet core of Example 1 by using a LCH 25 Lödige lab-coater (Gebruder Lödige Maschinenbau GmbH, Paderborn, Germany).

Example 4

GLP-1 Release of GLUTag Cells in Response to Different Active Compounds

[0090] Murine GLUTag cells (ATCC, Manassas, Va., USA) of 80% confluency were split from a T25 into 6 wells of a 12-well plate. On day 1, the resulting cells were 40-50% confluent and on day 2 the cells were 50-60% confluent. The cells were mostly single cells or very small aggregates; with no large aggregates observable.

[0091] Cells were gently washed 2 times with warm PBS (supplemented with calcium; D8662). Then, 300 μl of stimulation medium, either non-supplemented PBS as negative control or PBS supplemented with 10 μM FSK/IBMX (positive control), 10 mM glucose, 50 mM sucralose, 10 μM delphinidin 3-rutinoside or 100 μM oleoylethanolamide, were added to the cells. The cells were then incubated for 2 hours at 37° C.

[0092] The 300 μl of stimulation medium were removed from the well and centrifuged for 5 minutes. 200 μl of the supernatant were transferred to a fresh test tube and the samples were stored at −80° C. until subjected to GLP-1 measurement. The cells were discarded.

[0093] GLP-1 in the supernatant was measured using a commercially available ELISA (Mouse GLP-1 Elisa Kit, Chrystal Chem (Europe), Zaandam, The Netherlands) according to the manufacturer's instructions.

[0094] The results of this experiment are shown in FIG. 7 (A: data expressed as fold increase of measured GLP-1 concentration in the sample over negative control; B: data expressed as GLP-1 concentration in the supernatant after subtraction of signal measured in negative control).

[0095] In a further experiment, dose-response data of the stimulants glucose (at concentrations of 0.01 mM, 0.1 mM, 1 mM and 10 mM), oleoylethanolamide (at concentrations of 1 μM, 10 μM and 100 μM) and delphinidin 3-rutinoside (at concentrations of 10 μM, 50 μM, 100 μM and 500 μM) were measured as described above. The results are shown in FIG. 8A (glucose), 8B (ethanolamide) and 8C (delphinidin 3-rutinoside), respectively.

[0096] In another experiment, BSA (at a concentration of 0.5% (w/v)) was used as a peptidic stimulant of GLP-1 release by GLUTag cells. Again, stimulation medium alone (PBS) was used as negative control, and IBMX served as the positive control. The results are shown in FIG. 9.

Example 5

Burst Release of Components From the Inventive Pharmaceutical Oral Dosage Form In Vivo

[0097] In order to confirm that the components of the core of the pharmaceutical oral dosage form are released at the appropriate site in the small intestine, the following in vivo experiment was carried out:

[0098] A healthy volunteer was administered orally with a total of 5 g glucose using 5 units of the oral dosage form according to Example 3, with each tablet containing 1 g glucose. As described in Example 3, the unit dosages contained caffeine as tracer substance (25 mg caffeine per unit dose, 125 mg total amount administered). The administration of the oral dosage forms was carried out in the fasted state after overnight fastening and abstaining 48 hours before the administration of the oral dosage forms from any intake of caffeine-containing food or beverages.

[0099] Blood samples were collected from the volunteer before and 1 hour after administration of the oral dosage forms, and then continuing every 30 min until 6 hours post administration of the oral dosage forms. Blood samples were collected in P800 metabolic sample vacutainers (Becton Dickinson Co., Franklin Lakes, N.J., USA), immediately centrifuged (2000 rcf for 10 minutes at 4° C.), and the resulting supernatant plasma/serum was then transferred to a fresh tube and frozen on dry ice. Samples were stored at −150° C. until measurement of caffeine using a Caffeine ELISA Kit (BioVision Inc., Milpitas, Calif., USA) according to the manufacturer's instructions. The caffeine concentration in the blood samples were calculated by comparison to measured samples of caffeine standard concentrations included in the test kit.

[0100] The results are shown in FIG. 10 demonstrate a sharp increase in blood caffeine concentration starting at 3 hours post administration of the pharmaceutical oral dosage form of the invention corresponding to a burst release of the pharmaceutical oral dosage form in the terminal jejunum of the volunteer; cf. also FIG. 13 and FIG. 14.

Example 6

The Pharmaceutical Oral Dosage Form of the Invention Leads to a Pronounced Increase of GLP-1 Serum Concentration Following Burst Release in the Jejunum of a Subject

[0101] Parallel to the measurement of the tracer substance caffeine, GLP-1 concentrations were measured in the serum/plasma samples obtained from the volunteer according to Example 5. GLP-1 concentrations were measured using a commercially available ELISA test (GLP-1 7-36a Human ELISA Kit, ThermoFisher Corp., Waltham, Mass., USA) according to the manufacturer's instructions.

[0102] The results are shown in FIG. 11. The GLP-1 concentration raises sharply from 5 pmol/l to 10 pmol/l from 3 to 4 hours post administration of 5 pharmaceutical oral dosage forms of the invention each containing 1 g glucose (total dose of 5 g glucose). As the released active compound travels through the small intestine it reaches and triggers further L cells present in the downstream part (ileum) such that the GLP-1 concentration further increases to a value of almost 15 pmol/l after 6 hours post administration.

[0103] As shown in FIG. 12 and FIG. 13, the increase in GLP-1 concentration matches the burst release of the components of the pharmaceutical oral dosage form of the invention as measured by the caffeine concentration in the volunteer's blood serum.

[0104] From Evans et al. (1988) Gut 29, 1035-1041, the travelling times of pharmaceutical dosage forms of the type of dosage forms of the invention and pH distribution in the various parts of the human intestinal tract, and in particular of the small intestine, are known (see, in particular FIG. 3 on page 1038 of Evans et al. (1988); reproduced in present FIG. 14). In particular, the localization of the pH sensitive radiotelemetry capsule post oral intake have been assessed by Evans et al. (1988) as shown below in Table 4:

TABLE-US-00004 TABLE 4 Localisation of pH sensitive telemetry capsule in the gastro- intestinal tract (GI) in dependency of time after intake (according to Evans et al. (1988) Gut 29, 1035-1041) GI region Time (hours) after intake Duodenum 0.75 to 1.8 Jejunum 1.8 to 3.8 Ileum 3.8 to 5.4 Colon ≥5.4

[0105] Applying the data of Evans et al. (1988), the burst release of the components of the core of the pharmaceutical dosage form of the invention occurred in the (terminal) jejunum of the subject at a pH environment of >pH 7.0, and in particular ca. 7.3; cf. FIG. 13 and FIG. 14.

[0106] The in vivo data demonstrate that a comparatively low dose of 5 g glucose administered using the pharmaceutical oral dosage form of the invention is sufficient to markedly increase the GLP-1 serum concentration in humans. This effect can be likely attributed to the burst release of the core components from the inventive pharmaceutical oral dosage form in the jejunum of the subject.