3D-in-vitro-Permeationsmodell

Abstract

Permeation cell comprising a hollow body with at least two openings, characterized in that the at least two openings are each closed by at least one semipermeable membrane and the at least one semipermeable membrane comprises a mucous membrane.

Description

[0001] The present invention relates to a permeation cell, a device for measuring permeation, a method for measuring permeation and the use of such a permeation cell for determining permeation.

[0002] Permeation cells are generally closed containers made of a dimensionally stable material with at least one opening sealed by a permeable, particularly a semi-permeable, membrane. The permeation cell is filled with a medium that can diffuse through the permeable or semi-permeable membrane, or at least one substance contained or dissolved therein. The medium with which the permeation cell is filled is not further restricted and includes solutions, dispersions, suspensions, or (condensed) gases of various compositions. Permeation cells are frequently used to determine the permeability of the membrane under investigation. During the permeation measurement, the at least one permeable membrane of the permeation cell is preferably in contact with the medium inside the permeation cell on the one hand, and with a medium outside the permeation cell on the other. The permeation is determined, for example,by determining the change in permeate concentration. The type of membrane to be tested is not limited and thus extends to a wide variety of applications. Particularly in the medical field, for example, the membrane can be made of animal or human skin.

[0003] In pharmacology, oral administration of drug-containing thin films is widely used as an alternative drug formulation, so it may be of interest to determine the permeability coefficients of drugs released from oral thin films.

[0004] Oral thin films (OTFs) are thin films, usually containing a pharmaceutically active ingredient, that are placed directly into the oral cavity or applied to the oral mucosa, where they dissolve. These are, in particular, thin, polymer-based films containing active ingredients that, when applied to a mucous membrane, particularly the oral mucosa, release the active ingredient directly into it. These oral thin films are generally not sticky to the outside. The excellent blood flow to the oral mucosa ensures rapid transfer of the active ingredient into the bloodstream. This delivery system has the advantage that the active ingredient is largely absorbed through the mucosa, thus avoiding the "first-pass metabolism" that occurs with conventional tablet delivery, which is usually taken with liquid and can be disadvantageous.The active ingredient can be dissolved, emulsified or dispersed in the film.

[0005] Until now, standard in vitro models, e.g., the Franz cell, have not been able to accurately replicate the permeation of active substances into or through the mucosa under realistic conditions. It should be noted that the OTF in the oral cavity is subject to muscle and tongue movements, which lead to an increased actual absorption area. Therefore, the determined dissolution time of the OTF in conventional models is slower and the active substance uptake is lower than observed under realistic conditions. This deviation is primarily due to the fact that the available surface area and the amount of medium in the standard in vitro model are too small. Furthermore, standard in vitro models have several preparative disadvantages, such as the cumbersome attachment of the semipermeable membrane, the introduction of the test specimen, e.g.,of an OTF, due to the usually narrow opening of the standard in vitro models and the frequent changes of the medium outside the permeation cell due to the short change times.

[0006] EP 0 359 182 A1 relates to hollow fiber multimembrane permeator modules containing at least two different permeable membranes in a uniform multimembrane permeation cell.

[0007] EP 1 067 382 A2 describes a permeation cell for the in vitro monitoring of the permeation of pharmaceutical materials, comprising a donor chamber (34) and a separate acceptor chamber (4) with an intermediate window containing a skin membrane. The acceptor chamber is cylindrical and has a top closure (8) and a side window.

[0008] The present invention was therefore based on the object of eliminating the disadvantages of the prior art described above. In particular, the present invention was based on the object of providing a permeation cell which has a larger permeation area and is also capable of absorbing a higher volume of medium than previous standard in vitro models. Furthermore, the conditions prevailing in a patient's mouth, i.e. the fact that the OTF in the oral cavity is subject to muscle and tongue movements, which leads to an increased actual absorption area, are to be imitated as realistically as possible. Furthermore, handling is to be improved in that the permeation cell can be filled more quickly due to the easily accessible openings and the semipermeable membranes can be attached to the permeation cell more easily.

[0009] These objects were achieved by a permeation cell according to claim 1, ie by a permeation cell comprising a hollow body with at least two openings, which is characterized in that the at least two openings are each closed by at least one semipermeable membrane and the at least one semipermeable membrane comprises a mucous membrane.

[0010] Such a permeation cell has the advantage that the diffusion area is significantly increased by a 3-dimensional arrangement of the membrane, and that the available volume allows for a significantly larger amount of medium, allowing for in vitro permeation measurements that better reflect actual conditions. Furthermore, handling has been improved in that the permeation cell can be filled more quickly thanks to the easily accessible openings.

[0011] The terminology used in the description of the present disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the subject matter. As used in this description and the claims, the singular forms "a," "an," and "the" are intended to include the plural forms, unless the context clearly dictates otherwise. The reverse is also true, meaning that the plural forms are intended to include the singular forms. It is also to be understood that the term "and / or," as used herein, refers to and includes all possible combinations of one or more of the related listed elements.It is further understood that the terms "includes", "including", "comprises" and / or "comprising", when used in the present description and claims, specify the presence of the stated features, steps, elements and / or components, but do not preclude the presence or addition of one or more other features, steps, elements, components and / or groups thereof.

[0012] In the present description and claims, the terms "includes", "comprises" and / or "comprising" may also mean "consisting of", ie the presence or addition of one or more other features, steps, elements, components and / or groups is excluded.

[0013] The present invention relates to a permeation cell comprising a hollow body with at least two openings, wherein the at least two openings are each closed by at least one semipermeable membrane.

[0014] A hollow body is understood, in particular, to be a body whose interior is hollow, creating a volume that can be filled. The shape of the hollow body can be designed in various ways and is not subject to any restrictions. In particular, it does not have to have a continuous surface, so a hollow body is also not limited in the number of openings it can have. Consequently, the number of openings can be adapted to the respective technical requirements.

[0015] The at least two openings in the hollow body are preferably designed so that they can be closed, in particular with a semipermeable membrane, which is preferably held in position by corresponding holding devices. Suitable holding devices include, for example, elastic bands or rings, but also clamps, adhesive tapes or other adhesive devices. Multiple openings can also be closed by one and the same semipermeable membrane. In this case, the surfaces of the openings are preferably completely covered, resulting in a continuous surface consisting of the hollow body and the closed opening. The corresponding holding devices can, on the one hand, ensure the secure hold of the semipermeable membrane, and on the other hand, they also allow the reversible opening and closing of the hollow body.The holding device can be designed in various ways, ensuring that the semipermeable membrane to be attached is not damaged during attachment and removal, and that continuous contact of the semipermeable membrane with the edges of the opening is ensured. Furthermore, the holding devices can be mounted so that one semipermeable membrane covers multiple openings.

[0016] A semipermeable membrane is generally a semipermeable membrane that selectively allows molecules from an adjacent medium to diffuse through (permeate) while retaining others (retentate). Semipermeable membranes can be made from synthetic polymer films, cell membranes, parchment, or animal or human skin.

[0017] The passage of substances occurs according to the general principle of permeation, whereby the molecules sorb on the surface of the semipermeable membrane, diffuse to the other side, and desorb there again. Without external influences, the permeate always moves in the direction of lower concentration, more precisely along the gradient of the permeate's chemical potential.

[0018] A mucous membrane (tunica mucosa or mucosa for short) is a protective layer that lines the interior of hollow organs. Mucous membranes are found, among other places, in the oral and nasal cavities. Unlike external skin, the mucous membrane has neither a stratum corneum nor hair. The function of the mucous membrane is to prevent the penetration of foreign substances and the drying out of body tissue; moreover, most mucous membranes secrete mucous substances. When using a mucous membrane as the sealing membrane of the permeation cell according to the invention, it is important in one embodiment to ensure that the epithelium of the mucous membrane faces the interior of the permeation cell according to the invention.

[0019] The mucous membrane preferably comprises a human or animal mucous membrane, preferably a buccal mucosa or esophagus.

[0020] Membranes of various origins and thicknesses can be used for in vitro permeation measurements, including both animal and human mucosa. Overall, the Göttingen minipig mucosa has proven to be a good alternative to human mucosa due to comparable results and minimal differences in skin quality. The resulting skin thickness varies between 0.5 and 1.2 mm depending on the preparation.

[0021] The mucous membrane preferably comprises oral mucosa, in particular buccal mucosa, particularly preferably the esophagus of the domestic pig or Göttingen mini-pig.

[0022] The permeation cell according to the invention is further preferably characterized in that the hollow body has a volume of 1 to 5 cm 3 , preferably from 1 to 4 cm 3 , particularly preferably from about 1.5 to about 3 cm 3 , has.

[0023] The volume of the hollow body preferably corresponds to the hollow volume of the hollow body, whereby the volume is limited by the surface of the hollow body when the openings are closed.

[0024] The permeation cell according to the invention is further preferably characterized in that the total area of the semipermeable membranes is from 2 to 12 cm 2 , preferably from 2.5 to 10 cm 2 , particularly preferably from about 3 to about 9 cm 2 , amounts.

[0025] The total area of the semipermeable membranes is the sum of the areas of the individual semipermeable membranes. The area of the individual membranes considered preferably corresponds to the area of the closed opening, so that the areas that only serve for fastening or protrude need not be considered.

[0026] The single semipermeable membrane is further preferably characterized in that it has an area of 1 to 6 cm 2 , preferably from 1 to 5 cm 2 , particularly preferably from about 1.5 to about 4.5 cm 3 , has.

[0027] The permeation cell according to the invention is further preferably characterized in that the hollow body comprises a material selected from the group of polymers, preferably polystyrene.

[0028] In principle, the material used is not subject to any restrictions as long as it does not influence the permeation process, is chemically inert and sufficiently dimensionally stable.

[0029] The permeation cell according to the invention is further preferably characterized in that the hollow body has the shape of a hollow cylinder, a hollow cuboid, a hollow cube, a hollow pyramid, a hollow prism, a hollow cone and / or a hollow sphere, or a shape derived from these.

[0030] The shape of a hollow cylinder corresponds in particular to that of a right circular cylinder.

[0031] The other hollow bodies mentioned also essentially correspond to the general definitions in terms of their shape and determinants. Other shapes that can be derived from this include hollow bodies that can be derived from the aforementioned hollow bodies by simple adaptations, e.g., an oblique hollow cylinder. Furthermore, combinations of the listed bodies are also conceivable, such as a hollow pyramid whose base is flush with the surface of a hollow cube.

[0032] The invention further relates to a device for measuring a permeation of molecules through at least one semipermeable membrane, comprising the permeation cell according to the invention as a donor compartment, wherein the permeation cell contains a first medium comprising molecules, and an acceptor compartment containing a second medium, wherein the acceptor compartment is designed such that the second medium completely covers the semipermeable membranes of the permeation cell.

[0033] In connection with the device according to the invention for measuring the permeation of molecules, the term molecules includes all chemical compounds, ions or atoms that can diffuse through the at least one semipermeable.

[0034] In particular, the donor compartment is inserted into the device in such a way that it is completely covered by the acceptor compartment. This particularly applies to the semipermeable membranes. If necessary, the donor compartment can be attached or designed in different ways to ensure that it is completely covered throughout the measurement, e.g., by attaching it to a suitable location on the device.

[0035] The device according to the invention for measuring a permeation of molecules through at least one semipermeable membrane is further preferably characterized in that the molecules comprise at least one pharmaceutically active ingredient.

[0036] The at least one pharmaceutically active ingredient is in principle not subject to any restriction, but is preferably selected from all pharmaceutically active ingredients that are suitable for oral and / or transmucosal administration.

[0037] According to the present invention, the pharmaceutically active ingredient also includes all pharmaceutically acceptable salts and solvates of the respective pharmaceutically active ingredient.

[0038] Preferably, active ingredients are selected from the group comprising the active ingredient classes of analgesics, hormones, hypnotics, sedatives, antiepileptics, stimulants, psychoneurotropic agents, neuromuscular blockers, antispasmodics, antihistamines, antiallergics, cardiotonics, antiarrhythmics, diuretics, hypotensives, vasopressors, antidepressants, antitussives, expectorants, thyroid hormones, sex hormones, antidiabetics, antitumor agents, antibiotics, chemotherapeutics and narcotics, whereby this group is not exhaustive.

[0039] Particularly preferably, the at least one pharmaceutically active ingredient is ketamine and / or a pharmaceutically acceptable salt or solvate thereof, preferably ketamine HCl.

[0040] Ketamine is understood to mean (S)-(±)-2-(2-chlorophenyl)-2-(methylamino)cyclohexan-1-one, (R)-(t)-2-(2-chlorophenyl)-2-(methylamino)cyclohexan-1-one, and the racemate (RS)-(±)-2-(2-chlorophenyl)-2-(methylamino)cyclohexan-1-one.

[0041] The device according to the invention for measuring a permeation of molecules through at least one semipermeable membrane is further preferably characterized in that the first medium comprising the molecules comprises a solution, dispersion and / or suspension comprising at least one pharmaceutically active ingredient.

[0042] The first medium therefore comprises dissolved and / or undissolved molecules, in particular those that are able to diffuse through the semipermeable membrane.

[0043] The solvent and / or the liquid phase of the first medium preferably comprises or consists of water or a solution suitable for simulating oral conditions, with the use of water being preferred. Examples of solutions suitable for simulating oral conditions include physiological phosphate buffer, physiological phosphate buffer with thiocyanate, isotonic saline, human or animal saliva, or artificial human saliva (Glandosane or buffer).

[0044] The first medium is further preferably characterized in that this medium comprises the sample to be examined including the application of the OTF and an artificial saliva substitute solution, wherein this artificial saliva substitute solution preferably comprises potassium thiocyanate (KSCN), potassium chloride (KCI), sodium hydrogen phosphate hydrate (Na2HPO4*H2O), mucins (for example mucin from porcine stomach type II from Sigma Aldrich) and demineralized water.

[0045] Furthermore, the first medium is further preferably characterized in that it is adjusted to a pH of 6 to 8 by the addition of an acid and / or base, with the pH of 7 to 7.5, in each case at 37°C, being particularly preferred.

[0046] The first medium may further comprise suitable excipients. In particular, common excipients such as permeation accelerators are mentioned here.

[0047] The device according to the invention for measuring a permeation of molecules through at least one semipermeable membrane is further preferably characterized in that the second medium comprises at least one solvent, a buffer and / or a buffer with detergents, azides or the like.

[0048] The second medium preferably comprises or consists of water or a mixture of water and one or more organic solvents, with the use of water being preferred. For example, acetonitrile would be a suitable organic solvent.

[0049] The second medium is further preferably characterized by comprising a pH-regulating buffer. The buffer is preferably selected from the group consisting of a solution with a physiological salt concentration, with a phosphate buffer being particularly preferred. The phosphate buffer is particularly preferably made from potassium phosphate and / or sodium dihydrogen phosphate.

[0050] The second medium may further comprise suitable excipients to improve the solubility of the active ingredient in the second medium. In particular, excipients such as cyclodextrins or surfactants are mentioned here.

[0051] The device according to the invention for measuring a permeation of molecules through at least one semipermeable membrane is further preferably characterized in that the donor compartment is designed such that it has a higher density as a whole than the medium in the acceptor compartment.

[0052] The donor compartment is preferably characterized by having a higher density than the second medium to ensure, as described above, that it is completely covered by the second medium. This can be achieved, for example, by the first medium having a higher density than the second medium. Alternatively, the hollow body of the permeation cell or an additional material introduced into the permeation cell can result in a sufficiently high density or a sufficiently high weight of the donor compartment so that the buoyancy of the donor compartment is compensated or overcompensated.

[0053] Preferably, the hollow body comprises a material, such as a metal, which, when filled with the first medium, imparts to the hollow body an overall density so high that the semipermeable membranes are completely covered by the second medium when the permeation cell is placed in the acceptor compartment.

[0054] Alternatively, small, for example spherical, particles made of a material with a high density can be introduced into the permeation cell, i.e. into the volume of the hollow body, in order to give the permeation cell as a whole such a high density that the semipermeable membranes are completely covered by the second medium when the permeation cell is placed in the acceptor compartment.

[0055] Small particles that could be used here include metal beads with a diameter of approximately 1 to 8 mm, preferably approximately 2 to 6 mm. The metal beads are preferably made of stainless steel or lead.

[0056] The invention further relates to a method for measuring the permeation of molecules through at least one semipermeable membrane, comprising the steps: - Providing the permeation cell according to the invention as a donor compartment, wherein the permeation cell contains a first medium comprising molecules, - Providing an acceptor compartment comprising a second medium, - Place the permeation cell in the acceptor compartment so that the semipermeable membranes of the donor compartment are completely covered with the second medium.

[0057] Providing the permeation cell according to the invention as a donor compartment preferably comprises at least partially removing one of the semipermeable membranes and filling the permeation cell with the first medium. Preferably, the permeation cell according to the invention is filled to 70%, particularly preferably to 80%, of the volume of the hollow body of the permeation cell. Subsequently, the opening of the permeation cell is preferably closed again with a semipermeable membrane.

[0058] The incubation of the filled permeation cell according to the invention is preferably characterized in that the permeation cell is placed on a table shaker placed in the incubator at a temperature range of 25 to 38 °C, particularly preferably from 30 to 37 °C, and is rotated at 20 to 300 revolutions per minute (rpm), particularly preferably from 100 to 220 rpm, for 60 s to 30 min, particularly preferably for 3 to 10 min.

[0059] This procedure offers the advantage that the permeation cell according to the invention does not have to be completely filled and thus enables efficient homogenization of the first medium through the free volume, so that the soluble part of the OTF to be investigated can be dissolved in the first medium in a short time.

[0060] The provision of an acceptor compartment comprises in particular filling a suitable container, e.g. a beaker, with the second medium.

[0061] The acceptor compartment is further preferably characterized in that it can be adjusted to a temperature of 36 to 38°C, with the temperature of 37°C being particularly preferred, and / or has a stirring unit.

[0062] Placing the permeation cell in the acceptor compartment preferably involves placing the permeation cell in the acceptor compartment such that, in particular, the semipermeable membranes are completely covered by the acceptor compartment. If necessary, the donor compartment can be attached or designed in various ways to ensure that it is completely covered throughout the measurement.

[0063] The method according to the invention for measuring a permeation of molecules through at least one semipermeable membrane preferably further comprises the step of taking a sample from the acceptor compartment in order to determine a concentration of the molecules that have diffused through the semipermeable membranes of the donor compartment.

[0064] The sample is taken from the acceptor compartment using a suitable device, such as a pipette. The amount of sample taken can be compensated for by adding a medium, particularly one that matches the composition of the second medium. If the amount of sample taken is not compensated for, this can also be compensated for by adjusting the calculation basis for the next sample collection.

[0065] The amount of permeated molecules in the sample can be determined using suitable measurement methods. Such measurement methods include, for example, HPLC methods, but also other quantitative analysis methods, for example, based on mass spectrometry, NMR, IR, photometry, and / or titration.

[0066] The method according to the invention for measuring a permeation of molecules through at least one semipermeable membrane is further preferably characterized in that the sampling takes place over a period of 0.5 to 360 minutes, wherein samples are preferably taken regularly.

[0067] The method according to the invention for measuring a permeation of molecules is further preferably characterized in that samples are taken from the acceptor compartment at intervals of 1 to 60 min, for example at intervals of 3 min, 5 min, 10 min or 15 min, starting with the placement of the permeation cell in the acceptor compartment.

[0068] The invention further relates to the use of the permeation cell according to the invention or the device according to the invention for determining a permeation of molecules through at least one semipermeable membrane.

[0069] The preferred embodiments listed above for the permeation cell according to the invention also apply to the device according to the invention for measuring a permeation, the method for measuring a permeation and the use of such permeation cells for determining a permeation. Description of the characters Fig. 1: Schematic representation of a possible permeation cell according to the invention, using a straight hollow cylinder as the hollow body. The two openings are each sealed with a mucosa as a semipermeable membrane, with rubber bands used to hold the mucosa in place. Fig. 2: Schematic representation of a conventional 2D mucosal model. Fig.Figure 3: Schematic representation of the device for measuring permeation through two mucosae. The donor compartment comprises a preferred embodiment of the permeation cell, which is completely covered by the acceptor compartment. List of reference symbols 1 cell culture plate 2 Donors 3 Acceptor 4 Insert 5 Dissolved active ingredient 6 Mucosa 7 Prepared insert Examples

[0070] The invention is explained in more detail below using non-limiting examples.

[0071] To optimize and increase the surface area of the 2D standard in vitro model for measuring permeation of ketamine HCl-containing OTFs, various models such as the 2D overlay model and the permeation cell according to the invention were developed and investigated.

[0072] To determine the concentration, the samples were filtered and then analyzed using an HPLC system (Prominence-i LC-2030C 3D Plus from Shimadzu®) under the parameters listed in Table 1. Table 1: Parameters for the HPLC system Parameter: Method: Mobile phase Phosphate buffer: methanol: triethylamine, pH = 4.0 Stationary phase Modified silica gel (C18) Column oven temperature 40 °C Temperature Autosampler 15 °C flow rate 0.7 mL / min Injection volume 15 µL detector DAD: 220 nm Pressure 140 bar Retention time 4.5 minutes Example 1:

[0073] As a first example, the permeability of ketamine HCl-containing OTFs was determined using the 2D standard in vitro model (analog Fig. 2) measured.

[0074] For the 2D standard in vitro model, 6-well inserts and 12-well inserts were used, which were covered with a mucosa punch (4.524 cm2) and fixed with a rubber band.

[0075] To determine the amount of ketamine HCl permeating the mucosa, in vitro permeation experiments on mucosa were conducted. 1.7 mL of phosphate buffer (pH 7.4) was added to each well of a 6-well cell culture plate, which acted as the acceptor solution. Six cell culture plates were filled with the acceptor solution for specific exchange times of 3, 6, 9, 12, 15, 18, 21, 24, 27, and 30 minutes and preheated in an incubator at 37 °C. Subsequently, five prepared 6-well mucosal inserts were each filled with 200 µL of diluted saliva substitute solution (donor solution) using a pipette, and one ketamine HCl-containing OTF was applied to each insert using tweezers. Then, 300 µL of diluted saliva substitute solution was pipetted onto each OTF. To create the blank value, 500 µL of diluted saliva substitute solution was added to a prepared insert.

[0076] To start permeation and after filling the inserts in a storage plate, the first 6-well cell culture plate with the acceptor was removed from the incubator for the first 3-minute changeover time, and one insert was transferred to each well using tweezers. The 2D standard in vitro model cell culture plate was then incubated in a thermoshaker at 37 °C and 350 rpm for 3 minutes. For the acceptor change after 3 minutes, the plate was removed from the thermoshaker and one insert was carefully transferred to a fresh well on a new, pre-warmed 6-well plate using tweezers. This process was continued for subsequent changes. The total incubation time was 30 minutes, with the acceptor being changed every 3 minutes. The collected samples were subsequently analyzed using an HPLC system. Table 2: Measured values from Example 1. Flux at the change time 3 minutes [µg / cm 2 * min] Average flux (J a )[µg / cm 2 * min] Steadystate-Flux (J ss ) Permeability coefficient (K P ) * Normalized permeated amount [µg / cm 2 ] 6,266 29,320 34,420 6,125 892 Example 2:

[0077] As a second example, the permeability of a ketamine HCl-containing OTF was determined using the 2D overlay model (analog Fig. 3) measured.

[0078] For the 2D overlay model, 6-well inserts and 12-well inserts were used, which were filled with a mucosal punch (4.524 cm 2 ) and secured with a rubber band. Additionally, another rubber band was pulled around the holders of the 6-well insert in the cell culture plate. This rubber band acted as a holder for the 12-well insert during permeation. A mucosa punch (1.131 cm 2 ) in reverse orientation so that the epithelium of the mucosa faced the outside of the insert and thus epithelium to epithelium with the 6-well insert.

[0079] After inserting the mucosal punches into a 6-well and a 12-well insert, six 6-well cell culture plates were filled with acceptor (phosphate buffer, pH 7.4) for the specific exchange times of 3, 6, 9, 12, 15, 18, 21, 24, 27, and 30 minutes and prewarmed in an incubator. The five 6-well inserts were filled with diluted saliva substitute solution and one ketamine HCl-containing OTF each. The blank was again filled with 500 µL of diluted saliva substitute solution. To investigate drug permeation in both directions, 1 mL of acceptor solution was added to each of the six 12-well inserts. The 12-well inserts were then secured in the rubber holder of the filled 6-well insert for permeation and transferred into a pre-warmed 6-well cell culture plate using tweezers.

[0080] To start permeation and after filling the inserts in a storage plate, the first 6-well cell culture plate with the acceptor was removed from the incubator for the first 3-minute change, and one insert was transferred to each well using tweezers. The insert-loaded cell culture plate was then incubated in a thermoshaker at 37 °C and 350 rpm for 3 minutes. For the acceptor change after 3 minutes, the plate was removed from the thermoshaker, and one insert was carefully transferred to a fresh well on a new, preheated 6-well plate using tweezers. This process was continued for subsequent changes.The total incubation time was 30 minutes, with the acceptor being changed every 3 minutes. In addition to the complete removal of the acceptor from the cell culture plate, a partial removal of 0.5 mL from the acceptor solution of the respective 12-well insert was performed using a pipette into a centrifuge tube at each change time. After the partial removal, 0.5 mL of fresh acceptor solution was pipetted into each insert. The collected samples were then analyzed using an HPLC system. Table 3: Measured values from Example 2. Flux at the change time 3 minutes [µg / cm 2 * min] Average flux (J a )[ µ g / cm 2 * min] Steadystate-Flux (J ss ) Permeability coefficient (K P ) * Normalized permeated amount [µg / cm 2 ] 16,840 37,088 43,457 7,733 1136 Example 3:

[0081] As an example according to the invention, the permeability of a ketamine HCl-containing OTF was determined using the device according to the invention (analogous Fig. 4) measured.

[0082] For the in vitro measurement of permeation, the permeation cell according to the invention was used, whereby a straight hollow cylinder was used as the hollow body and the two openings were each filled with a mucosa (4.524 cm 2 ) as a semipermeable membrane. Rubber bands were used as a holding device.

[0083] To prepare the device according to the invention, 15 mL of the second medium, comprising a phosphate buffer with a pH of 7.4, was added to each well of a 6-deep-well cell culture plate using a Dispensette to moisten the substrate. The plate was then preheated in an incubator at 37°C. To fill the permeation cell according to the invention with 3 mL of diluted saliva substitute solution and the ketamine HCl-containing OTF, one of the two openings was not completely sealed with mucosa. Furthermore, the permeation cell according to the invention was filled with a weight for weighting; individual lead spheres with a total weight of 5 g were used for this purpose.After the previously created opening was closed with the mucosa and fixed with a rubber band, the permeation cell according to the invention was filled with 3 mL of diluted saliva substitute solution, the ketamine HCl-containing OTF, the weighting lead spheres and placed into the acceptor compartment with the mucosae openings closed as a donor compartment.

[0084] To determine the concentration, the prewarmed 6-deep-well plate was removed for the first changeover time of 3 minutes, and the permeation cell according to the invention and the blank were carefully placed into a well using tweezers. The same procedure was followed for the remaining changeover times of 6, 9, 12, 15, 18, 21, 24, 27, and 30 minutes. The loaded cell culture plate was then placed on a benchtop shaker in the incubator and incubated at 37 °C and approximately 200 rpm. The collected samples were then analyzed using an HPLC system. Table 4: Summary of the measured values from Example 1, Example 2, Example 3 and comparison of the measured values of Example 1 with Example 3. Example Flux at the change time 3 minutes [µg / cm 2 * min] Average flux (J a )[µg / cm 2 * min] Steadystate-Flux (J ss ) Permeability coefficient (K P ) * Normalized permeated amount [µg / cm 2 ] 1 6,266 29,320 34,420 6,125 892 2 16,840 37,088 43,457 7,733 1136 3 15,87 40,014 51,170 9,105 1250 Increase 1 vs 3 Factor 2.5 27% 32% 33% 29%

Claims

[1] Permeation cell comprising a hollow body with at least two openings, characterized by that the at least two openings are each closed by at least one semipermeable membrane and the at least one semipermeable membrane comprises a mucous membrane. [2] Permeation cell according to claim 1, characterized by that the at least one semipermeable membrane comprises an oral mucosa. [3] Permeation cell according to any one of the preceding claims, characterized by that the hollow body has a volume of 1 to 5 cm³. [4] Permeation cell according to any one of the preceding claims, characterized by that the total area of the semipermeable membranes ranges from 2 to 12 cm 2 amounts. [5] Permeation cell according to any one of the preceding claims, characterized by that the hollow body comprises a material selected from the group of polymers. [6] Permeation cell according to any one of the preceding claims, characterized by that the hollow body has the shape of a hollow cylinder, a hollow cuboid, a hollow cube, a hollow pyramid, a hollow prism, a hollow cone and / or a hollow sphere, or a shape derived from these. [7] Device for measuring a permeation of molecules through at least one semipermeable membrane, comprising a permeation cell according to any one of claims 1 to 6 as a donor compartment, wherein the permeation cell contains a first medium comprising molecules, and an acceptor compartment containing a second medium, wherein the acceptor compartment is designed such that the second medium completely covers the semipermeable membranes of the permeation cell. [8] Device according to claim 7, wherein the molecules comprise at least one pharmaceutically active agent. [9] Device according to claim 7 or 8, characterized bythat the first medium comprising the molecules comprises a solution, dispersion and / or suspension comprising at least one pharmaceutically active ingredient. [10] Device according to any one of claims 7 to 9, characterized by that the second medium comprises at least a solvent and a buffer. [11] Device according to any one of claims 7 to 10, characterized by that the donor compartment is designed in such a way that it has a higher density as a whole than the medium in the acceptor compartment. [12] Method for measuring permeation of molecules through at least one semipermeable membrane, comprising the steps: - Providing a permeation cell according to any one of claims 1 to 6 as a donor compartment, wherein the permeation cell contains a first medium comprising molecules, - Providing an acceptor compartment comprising a second medium, - Place the permeation cell in the acceptor compartment so that the semipermeable membranes of the donor compartment are completely covered with the second medium. [13] The method of claim 12, further comprising the step of taking a sample from the acceptor compartment to determine a concentration of the molecules that have diffused through the semipermeable membranes of the donor compartment. [14] Method according to claim 13, characterized by that sampling takes place over a period of 0.5 to 360 minutes, with samples preferably being taken at regular intervals. [15] Use of a permeation cell according to any one of claims 1 to 6 or a device according to any one of claims 7 to 11 for determining a permeation of molecules through at least one semipermeable membrane.

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