WO2021215039A1 - Method and device for evaluating oral absorbability of drug - Google Patents

Abstract

A method for evaluating the oral absorbability of a drug according to the present invention, said method comprising putting the drug or a drug-containing preparation into a simulated gastrointestinal fluid, allowing the drug in the simulated gastrointestinal fluid to permeate into a simulated blood through a drug-permeable membrane, and then measuring the drug concentration in the simulated gastrointestinal fluid and/or the simulated blood to thereby evaluate the oral absorbability of the drug or the drug in the preparation after oral administration, characterized in that the conditions of the simulated gastrointestinal fluid are changed with time so as to mimic the conditions in the stomach and then the conditions in the small intestine and, at the same time, the contact area between the simulated gastrointestinal fluid and the drug-permeable membrane is enlarged with time. According to this method, the absorbability of a drug into the blood circulating through the whole body, after the oral administration of the drug or a drug-containing preparation to a human being, can be evaluated at a high accuracy.

Description

Oral absorption evaluation method and device for drugs

The present invention relates to a method and an apparatus for accurately evaluating the absorption of an orally administered drug from the digestive tract.

A test to show that two formulations containing the same drug are bioequivalent and the same therapeutic effect can be expected after administration (bioequivalence test, hereinafter referred to as "BE (Bioequivalence) test"). .) Is carried out when approving a generic drug or changing the formulation at the time of clinical trial of a new drug, and is the most important process especially in the development of a generic drug. In order to show that the test preparation, which is a newly prepared preparation, is bioequivalent to the standard preparation, which is an existing preparation, that is, to meet the BE test, for oral preparations, the drug after administration of the preparation The difference between the maximum blood concentration (Cmax) and the area under the blood concentration-time curve (AUC) calculated from the transition of the blood concentration of the drug by measuring the blood concentration of the drug over time is within a certain range. It is required to be. Cmax is an index of drug absorption rate, and AUC is an index of drug absorption.

In the BE test of oral preparations in Japan, first, the dissolution property of the drug from the test preparation and the standard preparation is verified in vitro, and if the dissolution is judged to be similar, a clinical test in humans is carried out. The paddle method, rotary basket method, flow-through cell method, etc. are stipulated in the 17th revised Japanese Pharmacopoeia as methods for verifying drug elution from the drug before the human BE test. However, it is hard to say that these test methods reflect the actual physiological state in the gastrointestinal tract, and since they only evaluate the dissolution of the drug, they are highly accurate including the absorption into the systemic circulation blood. Verification is difficult.

As a process in which an orally administered solid preparation is absorbed into the blood, the preparation first stays in the stomach, where the disintegration of the preparation and the elution of the drug from the preparation begin. The drug moves from the stomach to the small intestine while eluting the drug. The eluted drug is also dissolved and absorbed in the solution in the stomach and small intestine while migrating in the same manner. Generally, the drug is hardly absorbed from the stomach, so absorption begins when the drug is transferred to the small intestine. At this time, the pH of the solution changes from acidic pH to neutral pH with the transition from the stomach to the small intestine, so that the drug in the solution dissolves or reprecipitates according to the pH. Since the only drug absorbed from the small intestine is the drug dissolved in the solution in the small intestine, the profile of dissolution / precipitation in the gastrointestinal tract greatly affects the absorption rate and amount of the drug. Furthermore, the effective surface area of the small intestinal mucosa involved in absorption from the small intestine increases with time as the solution is transferred, which affects the drug absorption rate particularly immediately after the start of absorption.
Therefore, in order to accurately evaluate the difference in drug absorption rate and absorption amount between pharmaceutical products in vitro, it is necessary to construct a system that can reproduce the above-mentioned in vivo behavior of the pharmaceutical product in the gastrointestinal tract. be.

Conventionally, various in vitro devices have been developed for the purpose of predicting the in vivo behavior of a pharmaceutical product in vivo.
For example, Non-Patent Document 1 uses a liquid feeding pump to sequentially feed a drug-containing liquid to a plurality of vessels simulating the stomach, duodenum, and jejunum, and the accompanying changes over time such as dissolution, dissolution, and precipitation of the drug. The system for observing ((Gastrointestinal Simulator (GIS))) is described.
However, in GIS, since the tube connecting the vessels does not exist in the human body, the difference in the migration efficiency of the solid formulation particles in the tube may cause the difference between the formulations, and in vivo. The behavior of the drug cannot be accurately reproduced. For example, the degree of mechanical crushing of the pharmaceutical particles during liquid feeding and the difference in the moving speed between the pharmaceuticals affect the evaluation result. It also differs from the human gastrointestinal tract in that it is difficult to move insoluble particles. Furthermore, since GIS does not include the process of membrane permeation, it is not possible to evaluate the actual amount of absorption. In addition, it is necessary to construct a complicated and expensive system including a computer system for controlling the liquid property and movement of the liquid in the vessel. In addition, due to the slow throughput, it takes a considerable amount of time to evaluate many test products.

In Non-Patent Document 2, the test drug is added to the solution in the gastrointestinal chamber and stirred by using a device in which the gastrointestinal chamber and the blood vessel chamber are connected via a small intestinal epithelial cell model membrane, and the small intestine is stirred. A system (Dissolution Permeation System (D / P system)) for measuring the concentration of a drug that has permeated the epithelial cell model membrane and transferred to the solution in the vascular chamber is described.
Since the D / P system measures the concentration of the drug that has permeated the membrane, it is suitable for evaluating the amount of drug absorbed. However, since the D / P system uses a solution with a certain composition such as a solution that imitates the stomach or a solution that imitates the small intestine as the solution in the gastrointestinal chamber, the solution composition due to the movement of the drug in the gastrointestinal tract It is not possible to reproduce changes in the environment such as pH. In addition, the increase in the effective drug absorption area of the small intestinal mucosa due to drug transfer cannot be reproduced. Therefore, it is not possible to reproduce the time course of drug elution, dissolution, and absorption in actual human in vivo. In particular, it is difficult to accurately evaluate the difference in absorption rate (Cmax) between formulations.

Further, Patent Document 1 uses a device in which a vascular chamber in which a part of the chamber wall is composed of a gastrointestinal model membrane is housed in a gastrointestinal vessel in which a rotating paddle is installed, and is used as a solution in the gastrointestinal vessel. We disclose a system (In vitro Dissolution Absorption System 2 (IDAS2)) that measures the concentration of a drug that has passed through a gastrointestinal model membrane and transferred to a solution in a vascular chamber by adding and stirring the test product.
IDAS2 is suitable for evaluating the amount of drug absorbed because it measures the concentration of the drug that has permeated the membrane after the drug has been eluted from the drug. However, in IDAS2, the pH of the solution in the gastrointestinal vessel is changed from the pH that imitates the stomach to the pH that imitates the small intestine. The change in pH of the environmental solution cannot be reproduced. In addition, the increase in the effective drug absorption area of the small intestinal mucosa due to drug transfer cannot be reproduced. Therefore, it is not possible to reproduce the time course of drug elution, dissolution, and absorption in actual human in vivo. In particular, it is difficult to accurately evaluate the difference in absorption rate (Cmax) between formulations. Also, like GIS, a large-scale device for installing the chamber is required, and it lacks versatility.

Furthermore, the bioequivalence test guidelines in Japan are currently being revised, and it is expected that human equivalence tests will be required not only during fasting but also after meals. Since many physiological factors such as liquid composition in the gastrointestinal tract, pH and transfer rate differ between fasting and feeding, a system capable of evaluating elution, dissolution and absorption of the drug from the pharmaceutical product under desired conditions is required. ..
The development of an in vitro system that solves the difficulties of conventional systems and can evaluate the bioequivalence of oral preparations easily and accurately will be extremely important in future drug development.

Patent No. 6386193

An object of the present invention is to provide a method and an apparatus capable of accurately evaluating the absorbability (absorption rate and absorption amount) of a drug into systemic circulating blood after oral administration of a drug or a drug-containing preparation to humans. do.

The present inventor repeated research in order to solve the above problems, and put a drug or a drug-containing preparation into a simulated gastrointestinal solution (a solution adjusted by imitating the composition and pH of the solution in the digestive tract) to perform simulated digestion. The drug in the tubule is permeated into the simulated blood through the drug permeable membrane, and in the simulated gastrointestinal tract fluid and / or in the simulated blood (a solution adjusted to imitate the composition and pH of the blood or a solvent such as octanol). In a method of evaluating the oral absorbability of a drug or a drug contained in an orally administered drug or a preparation by measuring the drug concentration of the solution (solution used by injecting into the blood vessel side chamber), a simulation of the injection of the drug or the drug-containing preparation is performed. The gastrointestinal fluid is used as a simulated gastric fluid (a solution adjusted by imitating the composition and pH of the solution in the stomach), and the liquidity and composition of the simulated gastrointestinal fluid are used to simulate the environmental change from the stomach to the small intestine. , The volume is changed from simulated gastric fluid to simulated small intestinal fluid (solution adjusted by imitating the composition and pH of the solution in the small intestine) at an arbitrary speed, and the contact area between the simulated gastrointestinal fluid and the drug permeable membrane. It has been found that a method of increasing the amount of water over time can solve the above-mentioned problems.

In the above method, the state of the simulated gastrointestinal fluid such as liquidity, composition, and volume is changed from the stomach to the small intestine over time to create an environment in the gastrointestinal tract where the drug actually administered to humans is placed. It can be reproduced. Therefore, the disintegration of the pharmaceutical product, the elution and dissolution of the drug in the human gastrointestinal tract can be accurately reproduced.
In addition, the drug that has moved from the stomach to the small intestine has a larger contact area with the mucous membrane of the small intestine as it moves in the small intestine, and the drug absorption rate increases accordingly. In the above method, not only the absorption amount of the drug (AUC) but also the absorption rate of the drug (Cmax) can be evaluated by increasing the contact area between the simulated gastrointestinal fluid and the drug permeable membrane over time. can.

The present invention has been completed based on the above findings, and provides the following [1] to [10].
[1] A drug or a drug-containing preparation is put into a simulated gastrointestinal fluid, and the drug in the simulated gastrointestinal fluid is permeated into the simulated blood through a drug permeable membrane, and the simulated gastrointestinal fluid and / or the simulated blood is used. It is a method of evaluating the oral absorbability of an orally administered drug or a drug in a preparation by measuring the drug concentration, in which the state of simulated gastrointestinal fluid is changed from the stomach to the small intestine over time, and at the same time. A method for evaluating oral drug absorption, which comprises increasing the contact area between a simulated gastrointestinal fluid and a drug permeable membrane over time.
[2] A gastrointestinal chamber for accommodating simulated gastrointestinal fluid, which is provided with a simulated gastrointestinal fluid pool at the bottom and has a mechanism for injecting concentrated simulated small intestinal fluid inside, and the inside of the gastrointestinal chamber is stirred. After pouring the simulated gastric fluid and the drug or drug-containing preparation into the simulated gastric fluid pool, the simulated gastrointestinal fluid to be generated is stirred while injecting the concentrated simulated small intestinal fluid into the simulated gastric fluid by the concentrated simulated small intestinal fluid injection mechanism. The method according to [1], wherein the state of the simulated gastrointestinal tract fluid is changed from the stomach to the small intestine over time.
[3] A vascular chamber for accommodating simulated blood, which is connected to the gastrointestinal chamber at a drug-permeable connection located above the simulated gastric fluid pool, is used, and a drug-permeable membrane is formed on the surface of the drug-permeable connection. The gastrointestinal chamber and the vascular chamber are separated from each other by being installed so that the direction is inclined with respect to the horizontal direction, and the concentrated simulated small intestinal juice is injected into the simulated gastric juice by the concentrated simulated small intestinal juice injection mechanism. The method according to [2], wherein the liquid level of the generated simulated gastrointestinal fluid is raised to increase the contact area between the simulated gastrointestinal juice and the drug permeable membrane over time.
[4] The vascular chamber is provided with a mechanism for injecting simulated blood into the inside, and by using this infusion mechanism, the height of the liquid level in the gastrointestinal chamber is matched with the height of the liquid level in the vascular chamber. The method according to [3], wherein the simulated blood is injected into the vascular chamber.
[5] The drug concentration in the simulated gastrointestinal fluid and / or the drug concentration in the simulated blood is measured over time to simulate the initial drug concentration increase rate in the simulated gastrointestinal fluid and / or the initial drug concentration increase rate in the simulated blood. The method according to any one of [1] to [4], wherein the oral absorbability of a drug is evaluated by calculating the area under the drug concentration-time curve of blood.
[6] The method according to any one of [1] to [5], wherein the state of the simulated gastrointestinal fluid that undergoes changes over time is pH, composition, and volume.
[7] It has a gastrointestinal tract chamber and a vascular chamber, and a simulated gastrointestinal fluid pool is provided at the bottom of the gastrointestinal tract chamber. It is connected by a connection part, and the drug permeable connection part is installed so that the surface direction of the drug permeable membrane is inclined with respect to the horizontal direction to separate the gastrointestinal tract chamber and the vascular chamber. The gastrointestinal chamber is provided with an inlet for injecting concentrated simulated small intestinal fluid, and the vascular chamber is provided with an inlet for injecting simulated blood inside, and the simulated gastrointestinal fluid is housed in the gastrointestinal chamber. A drug oral absorption evaluation device, which comprises a stirrer for agitating.
[8] An automatic liquid feeding device for injecting concentrated simulated small intestinal juice from the injection port of the gastrointestinal chamber and / or an automatic liquid feeding device for injecting simulated blood from the injection port of the vascular chamber is provided [7]. The device described in.
[9] (a) A device that automatically samples simulated gastrointestinal fluid and / or simulated blood, (b) A device that automatically samples simulated gastrointestinal fluid and / or simulated blood and automatically applies it to a drug measuring device. Or (c) equipped with an automatic monitoring device that automatically samples simulated gastrointestinal fluid and / or simulated blood, automatically applies it to a drug measuring device, and automatically measures the drug concentration by the drug concentration measuring device, [7] or [ 8].
[10] 7. Device.

The method of the present invention is by gradually changing the environment (simulated gastrointestinal fluid) in which the drug or the drug-containing preparation is placed after oral administration from the stomach to the small intestine without moving the drug or the drug-containing preparation. , It is possible to accurately reproduce the disintegration of the pharmaceutical product and the elution and dissolution of the drug when orally administered to humans.

In addition, the method of the present invention reflects the increase in the effective absorption area of the small intestinal mucosa due to the movement of the drug in the human gastrointestinal tract by increasing the contact area between the simulated gastrointestinal fluid and the drug permeable membrane over time. It is possible to evaluate the drug absorption. This makes it possible to accurately evaluate not only the amount of drug absorbed but also the rate of absorption. Therefore, AUC and Cmax can be predicted with high accuracy at the same time.

Thus, according to the method of the present invention, information on the disintegration, dissolution, dissolution, and absorption process of the pharmaceutical product after oral administration to humans can be sufficiently verified before the human BE test. can. Therefore, unnecessary clinical trials can be avoided, the number of subjects in clinical trials can be reduced, or the success rate of clinical trials can be increased.

Further, in the method of the present invention, the pH and composition of the simulated gastrointestinal tract fluid can be arbitrarily changed. For example, if the pH is changed from 1.6 to 6.5 over about 10 minutes, the environment becomes similar to the movement of the drug taken during fasting from the stomach to the small intestine. In addition, for example, if the pH is changed from 5 to 6.5 over about 30 minutes, the environment becomes similar to the movement of the preparation taken at the time of feeding from the stomach to the small intestine. Therefore, according to the method of the present invention, oral absorbability under various conditions such as fasting and feeding can be evaluated.
In addition, since the composition of the gastric fluid and the small intestinal fluid differs depending on the age and disease, the evaluation can be performed according to the subject by adjusting the composition of the simulated gastrointestinal fluid.
Further, when examining the change of the formulation, the enteric formulation, the sustained release formulation, etc. can be easily examined by arbitrarily changing the pH and composition of the simulated gastrointestinal fluid.

In addition, since the elution rate of the drug from the pharmaceutical product in the solution is affected by the drug concentration in the solution, the volume of the simulated gastrointestinal tract fluid affects the drug elution rate. As the pharmaceutical product administered to humans moves in the digestive tract, the amount of liquid in the surroundings changes. In the method of the present invention, since the volume of the simulated gastrointestinal fluid can be arbitrarily changed, the behavior of elution and dissolution of the drug in the human gastrointestinal tract can be accurately evaluated.
In addition, since the elution property of the drug is controlled by additives, coatings, layer structures, etc., the elution behavior of the pharmaceutical product cannot be evaluated if it is divided according to the volume of the simulated gastrointestinal fluid. In this respect, in the method of the present invention, since the volume of the simulated gastrointestinal tract fluid can be arbitrarily changed to approximate the volume of the human gastrointestinal tract fluid, the oral absorbability of not only the drug but also the drug-containing preparation is evaluated. can do.

Further, the method of the present invention does not require a complicated and expensive device because the state of the simulated gastrointestinal fluid can be changed only by controlling the injection rate of the concentrated simulated small intestinal juice. In addition, results can be obtained in a short time of about 60 to 120 minutes for one sample.

The device of the present invention is a simple and inexpensive device capable of carrying out the method of the present invention having such features.

It is a figure which shows one example of the apparatus of this invention. It is a figure which shows the elution rate and the membrane permeability of metoprolol tartrate from 20 mg of Seroken (registered trademark) tablet. It is a figure which shows the elution rate and the membrane permeability of telmisartan from a telmisartan (registered trademark) tablet under the fasting condition. It is a figure which shows the elution rate and the membrane permeability of telmisartan from a telmisartan tablet under the condition at the time of feeding. It is a figure which shows the human BE test result between the standard preparation under the fasting condition and the preparation A. It is a figure which shows the elution rate and the membrane permeability of the drug X from the standard preparation and the preparation A under the fasting condition. It is a figure which shows the human BE test result between the standard preparation under the feeding condition and the preparation A. It is a figure which shows the elution rate and the membrane permeability of the drug X from the standard preparation and the preparation A under the feeding condition. It is a figure which shows the human BE test result between the standard preparation under the fasting condition and the preparation B. It is a figure which shows the elution rate and the membrane permeability of the drug X from the standard preparation and the preparation B under the fasting condition. It is a figure which shows the human BE test result between the standard preparation under the feeding condition and the preparation B. It is a figure which shows the elution rate and the membrane permeability of the drug X from the standard preparation and the preparation B under the feeding condition. It is a figure which shows the elution rate and the membrane permeability of dipyridamole from Persantin (registered trademark) lock under the fasting condition. It is a figure which shows the elution rate and the membrane permeability of dipyridamole from a persantin tablet under the fasting condition. The pH was changed over a longer period of time than the method shown in Fig. 13. It is a figure which shows the elution rate and the membrane permeability of dipyridamole from a persantin tablet under the fasting condition. The pH was changed over a longer period of time than the method shown in Fig. 14. It is a figure which shows the elution rate and the membrane permeability of dipyridamole from a persantin tablet under the fasting condition. The pH at the start is higher than the method shown in Figures 13-15.

Hereinafter, the present invention will be described in detail.
(1) Drug Oral Absorption Evaluation Method In the method of the present invention, a drug or a drug-containing preparation is put into a simulated gastrointestinal tract fluid, and the drug in the simulated gastrointestinal tract fluid is permeated into the simulated blood through a drug permeable membrane. , A method for evaluating the oral absorbability of an orally administered drug or a drug in a preparation by measuring the drug concentration in the simulated gastrointestinal fluid and / or the simulated blood. This method is characterized in that the contact area between the simulated gastrointestinal fluid and the drug-permeable membrane is increased over time while changing from to the inside of the small intestine over time.

In the method of the present invention, not only a drug but also a drug-containing preparation can be evaluated. The formulations are solid formulations such as tablets, powders, granules, pills and capsules (soft capsules, hard capsules); liquid formulations such as liquids, elixirs, suspensions, emulsions, limonades and syrups. It may be either.
In the case of a pharmaceutical product, a single dose may be added to the simulated gastrointestinal tract fluid. In the case of a drug, the input amount may be determined according to the purpose of the test.

Examples of the "state" of the simulated gastrointestinal fluid that undergoes changes over time include pH, composition, volume, and the like.
The simulated gastrointestinal fluid at the time of adding the drug or the drug-containing preparation may be simulated gastric juice. Since the pH of human gastric juice is about 1 to 3 during fasting and about 2 to 6 after eating, the pH of simulated gastric juice should be about 1 to 3 when evaluating oral absorbability during fasting. , When evaluating the oral absorbability at the time of feeding, it should be about 2 to 6. For example, the pH can be adjusted by using a buffer solution such as an acetate buffer solution.
In addition, the simulated gastric juice may contain a digestive enzyme such as pepsin, sodium chloride, or the like, whereby the simulated gastric juice can be made to resemble a human gastric juice.

The volume of simulated gastric juice should be about 20 to 250 mL, especially about 50 to 200 mL. The volume of gastric fluid in human adults is about 20 to 50 mL, and solid preparations are often taken with water except for orally rapidly disintegrating tablets (in clinical trials, they are taken with 150 mL of water). If it is within the range, the evaluation can reflect the dissolution rate of the drug in the human stomach.

After the drug or drug-containing preparation is added to the simulated gastric juice, the drug may be dissolved by stirring the simulated gastric juice, or the drug-containing preparation may be disintegrated to dissolve the drug.

Then, the state of the simulated gastrointestinal fluid may be gradually brought closer to that of the human small intestinal fluid by gradually injecting the concentrated simulated small intestinal juice into the simulated gastric juice containing the drug. In addition, the simulated gastrointestinal fluid may be agitated while injecting the concentrated simulated small intestinal juice. The concentrated simulated small intestinal juice referred to here is for approximating the composition of the simulated gastrointestinal fluid to the simulated small intestinal juice by adding it to the simulated gastric juice, and its composition, addition amount, addition timing, etc. meet this purpose. Specific examples thereof include, but are not limited to, the following.
Since the pH of human small intestinal juice is about 6 to 8, the pH of concentrated simulated small intestinal juice may be about 6.5 to 10. For example, the pH can be adjusted by using a buffer solution such as a carbonate buffer solution, a Tris / HCl buffer solution, a HEPES buffer solution, or a phosphate buffer solution. By injecting concentrated simulated small intestinal juice in such a pH range, the pH of the simulated gastrointestinal fluid can be finally adjusted to about 6-8.
In addition, the concentrated simulated small intestinal juice may contain bile acids, lipids, sugars, digestive enzymes such as glycolytic enzymes, proteolytic enzymes, and lipid-degrading enzymes, thereby making the concentrated simulated small intestinal juice of humans. It can be approximated to small intestinal juice.

The amount of concentrated simulated small intestinal juice to be injected may be such that the amount of simulated gastrointestinal juice is finally about 50 to 500 mL, especially about 100 to 400 mL. Since the volume of the small intestinal fluid in a human adult is usually about 100 to 400 mL, an evaluation that reflects the absorption rate of the drug in the human small intestine can be performed within this volume range.

The injection time of the concentrated simulated small intestinal juice should be about 5 to 120 minutes, especially about 10 to 60 minutes. In the case of fasting evaluation, it may be about 5 to 20 minutes, especially about 10 minutes, and in the case of feeding evaluation, it may be about 20 to 120 minutes, especially about 30 to 60 minutes. This makes it possible to approximate the time it takes for the drug to travel from the stomach to the small intestine in actual humans.

The drug permeable membrane may be one in which the drug in the simulated gastrointestinal fluid permeates to the simulated blood side. For example, a cell layer membrane obtained by culturing cells, a gastrointestinal mucosa extracted from a human or non-human animal, an artificial lipid membrane, a porous membrane, and the like can be mentioned.
Examples of the cell layer membrane include those obtained by culturing cells in a single layer. Usually, cells cultured on a porous membrane so as to form a single layer can be used together with the porous membrane. The type of cell is not limited, but includes epithelial cells such as Caco-2 cells, C2BBel cells, MDCK cells, MDR-MDCK cells, BCRP-MDCK cells, HT-29 cells, and T-84 cells, especially the human small intestine. Caco-2 cells, which are widely used as model cells, are preferable.
As the excised gastrointestinal membrane, the small intestinal mucosa excised from humans or experimental animals such as rats, dogs, and monkeys can be used. In that case, all the excised submucosal tissues such as muscles can be used, or the submucosal tissues can be peeled off and used.
As the artificial lipid membrane, a phospholipid membrane or a lipid membrane formed by adding cholesterol or a membrane protein to phospholipid can be used. The lipid membrane can be used alone or formed on a porous membrane. As an example, PAMPA (Parallel Artificial Membrane Permeability Assay) in which an organic solvent solution such as phospholipid is applied to a membrane filter which is a porous membrane and a lipid membrane similar to a biological membrane is retained can be used.
The porous membrane (including the semipermeable membrane) preferably has a pore size of about 0.1 to 0.5 μm. Porous membranes with various pore sizes are commercially available. For example, as membrane filters, precision filtration membrane filters made of various materials are commercially available from Merck, and among them, Durapore (registered trademark) membrane filter (polyvinylidene fluoride membrane) and Millipore (registered trademark) filter (cellulose mixture). Ester membranes), Millipore Express Plus (polyether sulfone membranes), Isopore® membrane filters (track-etched polycarbonate membranes), hydrophobic polytetrafluoroethylene (PTFE) membranes, etc. are all available, all of which are preferred. Although it can be used, the Durapore membrane filter has less adsorption of proteins and the like, and can be particularly preferably used in the present invention.

When the drug permeable membrane is a cell layer membrane, an excised gastrointestinal membrane, or an artificial lipid membrane, a buffer solution having a pH of about 7.3 to 7.5, particularly about 7.4, which imitates blood can be used as the simulated blood. The buffer solution may be any one having a buffering ability at a pH of about 7.3 to 7.5, and examples thereof include a phosphate buffer solution, a HEPES buffer solution, and a Tris / hydrochloric acid buffer solution. In addition, plasma protein may be added to the simulated blood, whereby it can be approximated to human blood.
When the drug permeable membrane is a porous membrane, an organic solvent such as octanol, hexane or chloroform or an oil such as olive oil can be used as the simulated blood. Since the biological membrane contains phospholipids as the main component, the magnitude of distributability in the oil / water two-layer system is interpreted as an index of affinity for the biological membrane. , Can mimic drug permeation from the small intestine. Of these, octanol, which is widely used for measuring the distributiveness of drugs, is preferable.

The simulated gastrointestinal fluid may be brought into contact with the drug-permeable membrane at the same time as or thereafter when the concentrated simulated small intestinal juice is started to be infused, and the contact area thereof may be gradually increased. This makes it possible to reproduce the increase in effective small intestinal mucosal area in which the drug administered to humans can be absorbed.
Further, the drug permeable membrane may bring the region corresponding to the region in contact with the simulated gastrointestinal fluid into contact with the simulated blood. Therefore, the amount of simulated blood used may be gradually increased so that the contact area with the drug permeable membrane changes in this way.
The final contact area between the drug-permeable membrane and the simulated gastrointestinal fluid should be about ^{0.5 to 20 cm 2.} Therefore, a drug permeable membrane having an area of 0.5 to 20 cm ² or larger can be used.

After the contact between the simulated gastrointestinal fluid and the drug permeable membrane is started, one or both of the simulated gastrointestinal fluid and the simulated blood may be sampled over time to measure the drug concentration. It is preferable to sample both simulated gastrointestinal fluid and simulated blood over time.
The drug concentration in the simulated blood can be plotted against the elapsed time, and Cmax, which is an index of the absorption rate or the absorption rate in vivo, can be estimated from the initial slope of the increase in the drug concentration. Although it depends on the amount of simulated gastrointestinal fluid, the size of the drug permeable membrane, etc., the slope of 10 to 60 minutes after the drug concentration starts to rise is adopted because the absorption rate or Cmax in clinical tests can be estimated accurately. It is preferable to do so.
In addition, since the dissolution rate of the drug is an important factor that determines Cmax, the drug concentration in the simulated gastrointestinal fluid is plotted against the elapsed time, the drug dissolution rate is calculated from the initial inclination of the increase in the drug concentration, and the drug dissolution rate is obtained. The speed can be taken into account in the estimation of Cmax. It is preferable to adopt a slope of 10 to 60 minutes after the drug concentration begins to rise.
In addition, the amount of drug absorbed or AUC, which is an index thereof, can be estimated from the amount of drug permeation (or membrane permeability) up to a certain period of time. Although it depends on the amount of simulated gastrointestinal fluid, the size of the drug permeable membrane, etc., it is possible to accurately estimate the amount of drug absorbed or AUC in clinical trials. It is preferable to adopt the film permeation amount (or film permeability) for 120 minutes.

(2) Mechanism / Member for Performing Oral Drug Absorption Evaluation Method The drug oral absorbability evaluation method of the present invention described above can be performed using various mechanisms or members, and suitable examples are described below. explain.

The gastrointestinal chamber may be used to store the simulated gastrointestinal fluid. The upper surface of the gastrointestinal chamber may be open or covered with a lid.

In order to change the state of the simulated gastric juice from the stomach to the small intestine, first, a simulated gastric juice pool may be provided at the bottom of the gastrointestinal chamber. When the drug or drug-containing preparation is added to the simulated gastric juice placed in the simulated gastric juice pool, the state in which the drug or preparation has moved into the stomach is reproduced.

The capacity of the simulated gastric juice pool may be about 20 to 250 mL, especially a capacity that can accommodate about 50 to 200 mL of simulated gastric juice. The total volume of the gastrointestinal chamber including the simulated gastric juice pool may be about 50 to 500 mL, particularly about 100 to 400 mL, as long as it can accommodate the simulated gastrointestinal fluid.

Secondly, in order to change the state of the simulated gastrointestinal fluid from the stomach to the small intestine, the gastrointestinal chamber may be provided with a mechanism for injecting concentrated simulated gastrointestinal fluid into the inside. By gradually injecting the concentrated simulated small intestinal juice into the simulated gastric juice using this injection mechanism, the state (pH, composition, volume, etc.) of the simulated gastrointestinal fluid can be approximated to that of the small intestinal juice.
The injection mechanism may include, for example, an injection port provided in the gastrointestinal chamber and an automatic liquid delivery device. The inlet may be provided on the upper surface or the side surface of the gastrointestinal chamber, but the provision on the side surface, particularly on the side surface of the upper end of the simulated gastric juice pool, is excellent in reproducibility of the state in the human small intestine. preferable. Examples of the automatic liquid feeding device include those provided with a tube connected to an injection port and a liquid feeding pump. The liquid feed pump may be one that can keep the liquid feed rate constant or change it as planned.
The concentrated simulated small intestinal fluid infusion mechanism operates by adjusting the infusion rate and amount so that the state of the simulated gastrointestinal fluid reflects the movement of the drug or preparation taken by humans from the stomach to the small intestine. Is.

In order to change the state of the simulated gastrointestinal fluid from the stomach to the small intestine, thirdly, a mechanism for stirring the simulated gastrointestinal fluid in the gastrointestinal chamber may be used. This stirring mechanism may be capable of stirring the simulated gastric juice and the simulated gastrointestinal fluid obtained by injecting the concentrated simulated small intestinal juice.
Examples of the stirring mechanism include rotary blades or vibrating blades installed in the gastrointestinal chamber. Further, it may consist of a magnetic stirrer bar placed at the bottom of the gastrointestinal chamber and a magnetic stirrer placed outside the bottom surface of the gastrointestinal chamber. In addition, the internal liquid is agitated by vibrating the gastrointestinal chamber, the simulated gastrointestinal liquid is agitated by ultrasonic vibration, or a gas such as air or oxygen is blown into the simulated gastrointestinal liquid. The liquid may be agitated.
Since the stirring speed of the simulated gastrointestinal fluid affects the evaluation result of oral absorbability, the mechanism for stirring the simulated gastrointestinal fluid is preferably a rotary blade or a vibrating blade whose stirring speed can be easily controlled.

Sampling of simulated gastrointestinal fluid can be done manually. Alternatively, it can be performed using a mechanism for sampling the simulated gastrointestinal fluid at a predetermined time.
It is also possible to manually apply the sampled simulated digestive tract fluid to a drug concentration measuring device such as a high performance liquid chromatography device to measure the drug concentration, but the sampled simulated digestive tract fluid can be used as a drug concentration measuring device. An applying mechanism can also be used. Further, it is also possible to use an automatic monitoring device that samples the simulated gastrointestinal fluid at a predetermined time, applies it to the drug concentration measuring device, and measures the drug concentration by the drug concentration measuring device.

In the method of the present invention, a vascular chamber may be used to contain simulated blood. The vascular chamber is connected to the gastrointestinal chamber via a drug permeable connection, as described below. The upper surface of the vascular chamber may be open or covered with a lid. The gastrointestinal chamber and the vascular chamber may be in contact with each other with a common side wall, or may be separate containers.

The vascular chamber may be equipped with a mechanism for stirring the simulated blood inside. As the stirring mechanism, the same mechanism as the simulated gastrointestinal fluid stirring mechanism can be exemplified. Since the stirring rate of simulated blood does not affect the evaluation result of oral absorbability, it is convenient to use a magnetic stirrer bar placed at the bottom of the vascular chamber and a magnetic stirrer placed outside the bottom surface of the vascular chamber. ..

First, the gastrointestinal chamber and the vascular chamber are connected or communicated with a drug permeable connection in order to allow the drug in the simulated gastrointestinal fluid to permeate into the simulated blood through the drug permeable membrane. The drug permeable connection is provided on the common side surface of both chambers when the gastrointestinal chamber and the vascular chamber are in common side contact, and both containers when the gastrointestinal chamber and the vascular chamber are separate containers. It is provided as a passage between them. In any case, the drug permeable connection is located above the simulated gastric juice pool.
The lower end of the drug permeable connection is preferably located near the upper end of the simulated gastric juice pool, which allows monitoring of drug absorption immediately after the drug has moved to the small intestine.

Second, a drug permeable membrane is installed at the drug permeable connection in order to allow the drug in the simulated gastrointestinal tract fluid to permeate into the simulated blood via the drug permeable membrane. The gastrointestinal chamber and the vascular chamber are completely separated by a drug permeable membrane.

In order to increase the contact area between the simulated gastrointestinal fluid and the drug permeable membrane over time, the drug permeable membrane is installed at the drug permeable connection so that its surface direction is inclined with respect to the horizontal direction. NS. As a result, as the liquid level of the simulated gastrointestinal fluid in the gastrointestinal chamber rises, the contact area with the simulated gastrointestinal fluid increases. Above all, it is preferable that the drug permeable membrane is installed so that its plane direction is vertical. The drug-permeable membrane thus installed and the concentrated simulated small intestinal juice injection mechanism jointly increase the contact area between the simulated gastrointestinal fluid and the drug-permeable membrane over time.
The shape of the drug-permeable membrane is not particularly limited, and examples thereof include a circular shape, a quadrangular shape, a triangular shape, and a trapezoidal shape. Of these, an inverted triangle or a trapezoid whose upper side is longer than the lower side is preferable in that it approximates an increase in the effective drug absorption area of the actual human small intestine.

In order to bring the region corresponding to the region of the drug permeable membrane in contact with the simulated gastrointestinal fluid (the same region on the opposite side) into contact with the simulated blood, the vascular chamber is provided with a mechanism for injecting the simulated blood into the inside. Just do it.
The infusion mechanism may include, for example, an infusion port provided in the vascular chamber and an automatic fluid delivery device. The inlet may be provided on the upper surface or the side surface of the vascular chamber. Examples of the automatic liquid feeding device include those provided with a tube connected to an injection port and a liquid feeding pump. The liquid feed pump may be one that can keep the liquid feed rate constant or change it as planned.
This injection mechanism operates while adjusting the injection rate of simulated blood so that the liquid level in the gastrointestinal chamber and the liquid level in the blood vessel chamber are at the same level. This makes it possible to eliminate the effect of the difference in liquid level between the two chambers on the membrane permeation rate of the drug.

Sampling of simulated blood can be done manually. Alternatively, it can be performed using a mechanism for sampling simulated blood at a predetermined time.
Further, the sampled simulated blood can be manually applied to a drug concentration measuring device such as a high performance liquid chromatography device to measure the drug concentration, but a mechanism for applying the sampled simulated blood to the drug concentration measuring device is provided. It can also be used. Further, it is also possible to use an automatic monitoring device that samples simulated blood at a predetermined time, applies it to a drug concentration measuring device, and measures the drug concentration by the drug concentration measuring device.

The method of the present invention is preferably carried out using a temperature control device that keeps the temperature of each liquid used constant.
The temperature control device can keep at least the temperature of the simulated gastrointestinal fluid in the gastrointestinal chamber and / or the temperature of the simulated blood in the vascular chamber constant. Since the temperature affects the elution and dissolution of the drug, it is particularly preferable that the temperature of the simulated gastrointestinal fluid in the gastrointestinal chamber can be kept constant. Examples of the temperature control device include a heat medium circulation temperature control device and a heater attached to both chambers. The temperature control device may also be capable of keeping the temperature of the simulated gastric juice to be injected, the concentrated simulated small intestinal juice, and the simulated blood constant. In this case, a temperature control chamber accommodating all the mechanisms and members except the control device can be used.
Normally, the temperature of each liquid may be maintained at about 20 to 37 ° C., and above all, it may be maintained at around 37 ° C., which is the human body temperature.

(3) Oral drug absorption evaluation device The oral drug absorption evaluation device of the present invention has a gastrointestinal chamber and a vascular chamber, and a simulated gastric fluid pool is provided at the bottom of the gastrointestinal chamber, and the gastrointestinal chamber and the gastrointestinal chamber. The vascular chamber is connected by a drug permeable connection provided above the simulated gastric pool, and the drug permeable connection is such that the drug permeable membrane is tilted with respect to the horizontal direction. It is installed in the gastrointestinal chamber to separate the gastrointestinal chamber from the vascular chamber. The device is provided with an inlet and a stirrer for stirring simulated gastrointestinal fluid contained in the gastrointestinal chamber.

Each member is as described for the method of the present invention.

The device of the present invention can include an automatic liquid delivery device for injecting concentrated simulated small intestinal juice from the injection port of the gastrointestinal chamber and an automatic liquid delivery device for injecting simulated blood from the injection port of the vascular chamber. .. The automatic liquid feeding device is as described for the method of the present invention.

Further, the device of the present invention can be provided with a stirrer that agitates the simulated blood contained in the blood vessel chamber. The stirrer is as described for the method of the present invention.

Further, the device of the present invention can be provided with a mechanism for sampling simulated gastrointestinal fluid and / or simulated blood. The sampling mechanism may automatically sample each liquid at a predetermined time (over time). Further, a mechanism for applying the sampled simulated gastrointestinal tract fluid and / or simulated blood to a drug measuring device such as a high performance liquid chromatography device can be provided. Further, a drug concentration measuring device can be provided. It is also possible to provide an automatic monitoring device that automatically samples simulated gastrointestinal fluid over time, applies it to a drug concentration measuring device, and measures the drug concentration by the drug concentration measuring device.

The device of the present invention preferably includes a temperature control device capable of keeping at least the temperature of the simulated gastrointestinal fluid in the gastrointestinal chamber and / or the temperature of the simulated blood in the vascular chamber constant. The temperature control device may also be capable of keeping the temperature of the simulated gastric juice to be injected, the concentrated simulated small intestinal juice, and the simulated blood constant. The temperature control device is as described for the method of the present invention.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto.
(1) Drug Oral Absorption Evaluation Device An example of the drug oral absorption evaluation device of the present invention is shown in FIG.
The device comprises a gastrointestinal chamber 1 and a vascular chamber 2. The lumens of both chambers are cylindrical, and the top surfaces of both chambers are open.
The bottom of the gastrointestinal chamber 1 constitutes a gastric juice pool 1a. The height of the bottom surface of the vascular chamber is the same as the height of the upper end of the gastric fluid pool 1a. The shape of the gastric juice pool 1a is substantially hemispherical here, but is not particularly limited.
A concentrated simulated small intestinal juice injection port 1b is provided on the upper side wall of the gastric juice pool 1a. A tube 3a is connected to the concentrated simulated small intestinal juice injection port 1b so that the concentrated simulated small intestinal juice can be injected into the gastrointestinal chamber 1 using a pump 4a.
The gastrointestinal chamber 1 and the vascular chamber 2 communicate with each other by a drug permeable connection part 5. The drug permeable connection 5 is above the gastric pool 1a.
A drug permeable membrane 6 is installed in the drug permeable connection portion 5, and the gastrointestinal chamber side and the vascular chamber side of the drug permeable connection portion 5 are completely separated. The drug permeable membrane 6 is installed so that its plane direction is vertical. The drug permeable membrane 6 is a circular porous filter having a diameter of 47 mm (Merck Millipore, Durapore® Membrane, Type 0.22 μm PVDF Membrane).
The volume of the gastric juice pool 1a is 40 mL, and the volume of the gastrointestinal chamber 1 containing the gastric juice pool 1a is 100 mL.
Inside the gastrointestinal chamber 1, a rotary stirrer 7 having stirring blades at two positions above and below is installed coaxially with the lumen of the gastrointestinal chamber. One of the stirring blades is in a position where it can stir in the gastric fluid pool, and the other is above the gastric fluid pool.
A magnetic stirrer 8a is installed on the outside of the bottom surface of the vascular chamber, and a magnetic stirrer bar 8b is placed on the bottom surface inside the vascular chamber.
A simulated blood inlet 2b is provided on the side wall of the blood vessel chamber 2. A tube 3b is connected to the concentrated simulated small intestinal juice injection port 2b so that the simulated blood can be injected into the vascular chamber 2 using the pump 4b. The pump 4b can control the injection rate of the simulated blood so that the height of the simulated blood in the vascular chamber 2 is the same as the height of the simulated gastrointestinal fluid in the gastrointestinal chamber 1. ..
This device manually samples simulated blood and simulated gastrointestinal fluid, but it may be equipped with a device that samples them over time at the required timing and a device that applies it to a drug concentration measuring device. preferable.

An example of a method for evaluating the oral absorbability of a drug in a pharmaceutical product using the apparatus shown in FIG. 1 will be described. Taking the case of evaluating oral absorbability during fasting as an example, 40 mL of simulated gastric juice during fasting is placed in a gastric juice pool, and the test preparation is added thereto for one dose. Next, the simulated gastric juice is stirred with the rotary stirrer 7 to dissolve the drug. Then, by driving the pump 4a, the concentrated simulated small intestinal juice is injected from the concentrated simulated small intestinal juice inlet 1b through the tube 3a at a rate of 6 mL / min. Meanwhile, the rotary stirrer 7 stirs the simulated gastrointestinal fluid produced by mixing the simulated gastric juice and the concentrated simulated small intestinal juice. On the other hand, the simulated blood is injected into the vascular chamber 2 from the simulated blood injection port 2b via the tube 3b by driving the pump 4b so as to be at the same height as the simulated gastrointestinal fluid.
In each of the following tests, sampling of simulated gastrointestinal fluid was started 1 minute after the start of injection, and sampling of simulated blood was started 2 minutes after the start of injection, and then sampling was performed over time, using a high performance liquid chromatography device. The drug concentration was measured.
The drug concentration is plotted against time, and the slope of the graph for 45 minutes from the time when the drug concentration in the simulated blood begins to rise is used as an index of Cmax (absorption rate), and 120 minutes from the start of injection of concentrated simulated small intestinal fluid. The amount of membrane permeation was used as an index of AUC (absorption amount). In addition, the slope of the graph for 45 minutes from the time when the drug concentration in the simulated gastrointestinal fluid began to increase was taken as the drug dissolution rate in the gastrointestinal tract. The rate of drug dissolution in the gastrointestinal tract can be used as an auxiliary parameter in estimating Cmax from the rate of increase in drug concentration in simulated blood.

(2) Drug oral absorption evaluation test
(2-1) Preparation of reagents
Fasted state simulated gastrointestinal fluid (pH 1.6)
Sodium taurocholate 80 μM (11.7 mg)
Lecithin 20 μM
Sodium chloride 34.2 μM (398 mg)

Add the above ingredients to an appropriate amount of McIlvaine buffer adjusted to pH 4, make a solution, and finally make up to 200 mL. Then, adjust the pH to 1.6 with 5M hydrochloric acid. The composition of McIlvaine buffer is disodium hydrogen phosphate 0.02 M and citric acid 0.01 M.

Fasted state simulated gastrointestinal fluid (pH3.0)
In the above method for preparing simulated gastric juice during fasting (pH 1.6), except that the pH was adjusted to 3.0 instead of adjusting to pH 1.6 with 5 M hydrochloric acid, the simulated gastric juice during fasting (pH 3. 0) was prepared.

Pre-FaSSIF (Fasted state simulated intestinal fluid)
HBSS 50.028 mL
Sodium bicarbonate 174.996 mg
D-glucose 1250.004 mg
HEPES 1125 mg
Sodium taurocorate 5 mM (1092.996 mg)
Lecithin 1.25 mM

Add the above components to an appropriate amount of McIlvaine buffer adjusted to pH 4, make a solution, and finally make up to 300 mL (step 1). Next, as a trial calculation operation for the amount of sodium hydroxide for pH adjustment, 40 mL of FaSSGF and 60 mL of the solution prepared in step 1 are mixed, and the pH is adjusted to 6.5 with 5 M sodium hydroxide (step 2). Record the amount of sodium hydroxide required at this time. Add the amount of 5M sodium hydroxide required in step 2 to 60 mL of the solution prepared in step 1.

Fed state simulated gastrointestinal fluid (FeSSGF)
Sodium chloride 237.02 mM (2.77 g / 100 mL)
Acetic acid 17.12 mM (0.2056 g / 100 mL)
Sodium acetate 29.75 mM (0.488 g / 100 mL)

100 mL of milk (milk, commercially available) containing 3.5% fat is mixed with 100 mL of the acetate buffer having the above composition. Then adjust to pH 5.0 with 1M hydrochloric acid.

Pre-FeSSIF (Pre-Fed state simulated intestinal fluid)
HBSS 50.028 mL
Sodium bicarbonate 174.996 mg
D-glucose 1250.004 mg
HEPES 1125 mg
Sodium taurocholate 25 mM (5464.98 mg)
Lecithin 6.25 mM

Add the above components to an appropriate amount of McIlvaine buffer adjusted to pH 4, make a solution, and finally make up to 300 mL (step 1). Next, as a trial calculation operation for the amount of sodium hydroxide for pH adjustment, 40 mL of FeSSGF and 60 mL of the solution prepared in step 1 are mixed, and the pH is adjusted to 6.5 with 5 M sodium hydroxide. Record the amount of sodium hydroxide required at this time (step 2). Add the amount of 5M sodium hydroxide required in step 2 to 60 mL of the solution prepared in step 1.

(2-2) Empirical data 1 (Effect of rotation speed of rotary stirrer in gastrointestinal chamber)
40 mL (pH 1.6) of simulated gastric juice during fasting and 20 mg of Seroken tablets were placed in the gastric juice pool 1a of the gastrointestinal chamber 1 of the device shown in FIG. While stirring with the rotary stirrer 7, the fasting simulated small intestinal juice was injected into the gastrointestinal chamber 1 at a flow rate of 6 mL / min for 10 minutes to obtain 100 mL of the fasting simulated small intestinal juice having a pH of 6.5. The stirring speed by the rotary stirrer 7 was set to 50 rpm, 100 rpm, or 200 rpm.
Octanol, which is simulated blood, was injected into the vascular chamber 2 at a flow rate of 2.5 mL / min over 10 minutes to obtain a final volume of 25 mL.

Concentrated simulated small intestinal juice is injected into the gastrointestinal chamber. Simulated gastrointestinal juice and simulated blood are sampled over time for 120 minutes from 1 minute after the start of injection, and the concentration of metprorol tartrate, which is the active ingredient of Seroken tablets, is analyzed by high performance liquid chromatography. Measured by chromatography. Furthermore, the elution rate of metoprolol tartrate from the tablets at each time point (percentage of the amount of metoprolol tartrate in the simulated gastrointestinal tract fluid at each time point to the amount of metoprolol tartrate in one tablet) (%) was calculated. In addition, the membrane permeability of metoprolol tartrate at each time point (percentage of the amount of metoprolol tartrate in simulated blood at each time point to the amount of metoprolol tartrate in one tablet) (%) was calculated.

The result is shown in figure 2. It can be seen that the elution rate and membrane permeability of the drug change when the stirring rate of the simulated gastrointestinal fluid is changed.

(2-3) Empirical data 2 (Comparison between formulations of telmisartan-containing tablets)
40 mL (pH 1.6) of simulated gastric juice during fasting or 40 mL (pH 5.0) of simulated gastric juice during feeding and 20 mg of telmisartan tablets were placed in the gastric juice pool 1a of the gastrointestinal chamber 1 of the device shown in FIG. In the fasting condition experiment, the concentrated simulated small intestinal juice during fasting was injected into the gastrointestinal chamber 1 at a flow rate of 6 mL / min for 10 minutes while stirring with the rotary stirrer 7, so that the pH was 6.5 during fasting. The simulated small intestinal juice was 100 mL. In the experiment of feeding conditions, pH 6.5 was obtained by injecting simulated small intestinal juice during feeding into the gastrointestinal chamber 1 at a flow rate of 2 mL / min for 30 minutes while stirring with a rotary stirrer 7. The simulated small intestinal juice at the time of feeding was 100 mL. The stirring speed by the rotary stirrer 7 was set to 50 rpm.
In the fasting experiment, octanol, which is simulated blood, was injected into the vascular chamber 2 at a flow rate of 2.5 mL / min over 10 minutes to give a final volume of 25 mL. In the experiment under feeding conditions, octanol was injected into the vascular chamber 2 at a flow rate of 0.833 mL / min over 30 minutes to give a final volume of 25 mL.
As the telmisartan tablet, a preparation manufactured by Boehringer Ingelheim Co., Ltd. was used as a standard preparation, and preparations A and B having different additives were used for comparison.

Concentrated simulated small intestinal juice is injected into the gastrointestinal chamber From 1 minute to 120 minutes, simulated gastrointestinal juice and simulated blood are sampled over time, and the concentration of thermisartan, which is the active ingredient of thermisartan tablets, is measured by high performance liquid chromatography. It was measured. Furthermore, the elution rate of telmisartan from the tablets at each time point (percentage of the amount of telmisartan in the simulated gastrointestinal fluid at each time point to the amount of telmisartan in one tablet) (%) was calculated. In addition, the membrane permeability of telmisartan at each time point (percentage of the amount of telmisartan in simulated blood at each time point to the amount of telmisartan in one tablet) (%) was calculated.

The results of the fasting conditions are shown in Fig. 3, and the results of the fasting conditions are shown in Fig. 4. Under fasting conditions, there was a large difference in the elution rate of telmisartan between the formulations. On the other hand, under the feeding conditions, although there was a slight difference in the permeability of telmisartan between the formulations, there was no significant difference. It turns out that it is difficult to detect.
It can be seen that the method and apparatus of the present invention can evaluate the difference in oral absorbability between fasting and feeding.

(2-4) Empirical data 3 (Comparison between oral absorption evaluation results of drug X and clinical trial results)
Under the same conditions as in "(2-3) Empirical data 2", the elution rate and membrane permeability of drug X from the drug X-containing preparation were measured. As the drug X-containing preparation, the standard preparation and the preparations A and B having different additives were used.
In addition, after administering one tablet of the standard preparation, the preparation A, or the preparation B to a healthy subject, the drug X concentration in plasma was measured for 12 hours. This is a BE test in humans between the standard formulation and formulation A or formulation B.
The BE test was conducted according to the bioequivalence test guidelines for generic drugs in Japan. To explain the outline, it was a crossover study in which the standard preparation and the test preparation (formulation A or preparation B) were administered to the same subject with a drug holiday of 3 days or more. The subject was in a sitting position from the start of administration to 4 hours after administration, and was not in a standing or lying position except at the time of examination and in the toilet. The subject's drinking water was controlled from 1 hour before administration of each preparation to 4 hours after administration, except for drinking water for taking the preparation. The eating conditions were a high-fat diet (900 kcal or more, and the ratio of lipid energy to total energy was 35% or more) within 20 minutes, and the preparation was administered within 10 minutes after eating.

Figure 5 shows the results of the BE test in humans between the standard formulation under fasting conditions and formulation A. In addition, Fig. 6 shows the results of the dissolution rate and membrane permeability of drug X from the standard preparation and the preparation A under the feeding conditions.
The plasma concentration of drug X in the human BE test was lower for the standard preparation than the standard preparation, and the dissolution rate and the membrane permeability were lower than the standard preparation for the preparation A.

Figure 7 shows the results of the BE test in humans between the standard preparation under the feeding conditions and the preparation A. In addition, Fig. 8 shows the results of the elution rate and membrane permeability of drug X from the standard preparation and the preparation A under the feeding conditions.
The plasma concentration of drug X in the human BE test was lower for the standard preparation than the standard preparation, and the dissolution rate and the membrane permeability were lower than the standard preparation for the preparation A.
In the BE test, the difference in plasma drug X concentration between the standard preparation and the preparation A was larger during the fasting than during the fasting, which is consistent with the dissolution rate at the time of fasting. In comparison, the difference in dissolution rate between the standard preparation and the preparation A was larger when eating.

Figure 9 shows the results of the BE test in humans between the standard formulation under fasting conditions and formulation B. In addition, the results of the elution rate and membrane permeability of the drug X from the standard preparation and the preparation B under the fasting condition are shown in FIG.
The plasma concentration of drug X in the human BE study was higher with the standard preparation immediately after administration, but was higher with the preparation B thereafter. On the other hand, the dissolution rate and the membrane permeability of the preparation B were higher than those of the standard preparation. The elution rate and membrane permeability results were close to those of the human BE test.

Figure 11 shows the results of the BE test in humans between the standard preparation under the feeding conditions and the preparation B. In addition, the results of the dissolution rate and membrane permeability of drug X from the standard preparation and the preparation B under the feeding conditions are shown in FIG.
The plasma concentration of drug X in the human BE study was higher for the preparation B than for the standard preparation. On the other hand, the dissolution rate was slightly higher in the standard preparation, and the membrane permeability was slightly higher in the preparation B. The elution rate and membrane permeability results were close to those of the human BE test.

From the above test results using the method and apparatus of the present invention, it is predicted that the product A has poorer oral absorbability than the standard product, and the product B has the same or better oral absorbability as the standard product. The prediction was consistent with the BE test results in humans.
According to the method and apparatus of the present invention, it can be seen that the human BE test result can be predicted accurately.

(2-5) Empirical data 4 (Effect of gastric emptying rate)
40 mL (pH 1.6) of simulated gastric juice during fasting and one 25 mg of Persantin tablets were placed in the gastric juice pool 1a of the gastrointestinal chamber 1 of the device shown in FIG. While stirring with the rotary stirrer 7, the fasting concentrated simulated small intestinal juice is placed in the gastrointestinal chamber 1 over 10 minutes (flow rate 6 mL / min), 20 minutes (flow rate 3 mL / min), or 30 minutes (flow rate 2 mL / min). By injecting into, 100 mL of simulated small intestinal juice at the time of fasting at pH 6.5 was prepared. The stirring speed by the rotary stirrer 7 was set to 50 rpm, 100 rpm, or 200 rpm.
Octanol, which is simulated blood, was injected into the vascular chamber 2 over 10 minutes (2.5 mL / min), 20 minutes (1.25 mL / min), or 30 minutes (0.83 mL / min) to obtain a final volume of 25 mL. ..

Concentrated simulated intestinal juice is injected into the gastrointestinal chamber From 1 minute to 120 minutes, simulated gastrointestinal juice and simulated blood are sampled over time, and the concentration of dipyridamole, the active ingredient of Persantin tablets, is measured by high performance liquid chromatography. It was measured. Furthermore, the elution rate of dipyridamole from the tablets at each time point (percentage of the amount of dipyridamole in the simulated gastrointestinal fluid at each time point to the amount of dipyridamole in one tablet) (%) was calculated. In addition, the membrane permeability of dipyridamole at each time point (percentage of the amount of dipyridamole in simulated blood at each time point to the amount of dipyridamole in one tablet) (%) was calculated.

The results are shown in FIGS. 13, 14, and 15. The time taken to change the pH of the simulated gastrointestinal fluid in the gastrointestinal chamber from pH 1.6 to 6.5 was 10 minutes in FIG. 13, 20 minutes in FIG. 14, and 30 minutes in FIG.
When the pH change rate is changed, the drug elution rate and the membrane permeability are changed. Further, the elution rate and membrane permeability of the drug are affected by the stirring rate, but the degree of influence of the stirring rate differs depending on the pH change rate.
Since the method and apparatus of the present invention can arbitrarily set the stirring rate and the change rate of pH of the simulated gastrointestinal fluid in the gastrointestinal chamber, oral absorption in various humans with different gastrointestinal movements and gastric emptying rates. It can be seen that the sex can be evaluated accurately.

(2-6) Empirical data 5 (Effect of gastric pH)
40 mL (pH 3.0) of simulated gastric juice during fasting and one 25 mg of Persantin tablets were placed in the gastric juice pool 1a of the gastrointestinal chamber 1 of the device shown in FIG. While stirring with a rotary stirrer 7 at a stirring speed of 100 rpm, the fasting concentrated simulated small intestinal juice was applied for 10 minutes (flow rate 6 mL / min), 20 minutes (flow rate 3 mL / min), or 30 minutes (flow rate 2 mL / min). By injecting into the gastrointestinal chamber 1, 100 mL of simulated small intestinal juice at the time of fasting at pH 6.5 was obtained.
Octanol, which is simulated blood, was injected into the vascular chamber 2 over 10 minutes (2.5 mL / min), 20 minutes (1.25 mL / min), or 30 minutes (0.83 mL / min) to obtain a final volume of 25 mL. ..

Concentrated simulated intestinal juice is injected into the gastrointestinal chamber From 1 minute to 120 minutes, simulated gastrointestinal juice and simulated blood are sampled over time, and the concentration of dipyridamole, the active ingredient of Persantin tablets, is measured by high performance liquid chromatography. It was measured. Furthermore, the elution rate of dipyridamole from the tablets at each time point (percentage of the amount of dipyridamole in the simulated gastrointestinal fluid at each time point to the amount of dipyridamole in one tablet) (%) was calculated. In addition, the membrane permeability of dipyridamole at each time point (percentage of the amount of dipyridamole in simulated blood at each time point to the amount of dipyridamole in one tablet) (%) was calculated.

The results are shown in Fig. 16. The drug elution rate and membrane permeability are different from the results shown in FIGS. 13 to 15 when the pH in the gastrointestinal chamber 1 at the start of the test was 1.6. Further, as described above, the elution rate and the membrane permeability of the drug are affected by the pH change rate, but the degree of influence of the pH change rate is also different from the results shown in FIGS. 13 to 15. Since the gastric pH differs depending on the human even during the same fasting, it can be seen that the method and apparatus of the present invention can accurately evaluate the oral absorption in various humans.

Since the method and apparatus of the present invention can accurately predict the absorption of an orally administered preparation in humans, the burden of the human BE test performed when developing a generic drug or changing the design of a preparation is reduced. It is also very useful in that it can evaluate oral absorbability under various conditions.

Claims (10)

1. A drug or drug-containing preparation is injected into the simulated gastrointestinal tract fluid, and the drug in the simulated gastrointestinal tract fluid is permeated into the simulated blood through a drug permeable membrane to adjust the drug concentration in the simulated gastrointestinal fluid and / or simulated blood. It is a method of evaluating the oral absorbability of a drug administered orally administered or a drug in a preparation by measuring, and the state of the simulated gastrointestinal fluid is changed over time from the stomach to the small intestine, and the simulated digestive tract is used. A method for evaluating oral drug absorption, which comprises increasing the contact area between a liquid and a drug permeable membrane over time.
2. A gastrointestinal chamber that houses simulated gastrointestinal fluid, and has a gastrointestinal chamber with a simulated gastric fluid pool at the bottom and a mechanism for injecting concentrated simulated small intestinal fluid into the inside, and a mechanism for stirring the inside of the gastrointestinal chamber. By injecting the simulated gastric fluid and the drug or drug-containing preparation into the simulated gastric fluid pool, and then injecting the concentrated simulated small intestinal fluid into the simulated gastric fluid by the concentrated simulated small intestinal fluid injection mechanism, the simulated gastrointestinal fluid to be generated is stirred. The method according to claim 1, wherein the state of the simulated gastrointestinal fluid is changed from the stomach to the small intestine over time.
3. A vascular chamber for accommodating simulated blood is used, which is connected to the gastrointestinal chamber at a drug-permeable connection located above the simulated gastric fluid pool, and a drug-permeable membrane is horizontal to the drug-permeable connection. It is installed so as to have an inclination with respect to the direction so that the gastrointestinal chamber and the vascular chamber are separated, and the simulated small intestinal juice is generated by injecting the concentrated simulated small intestinal juice into the simulated gastric juice by the concentrated simulated small intestinal juice injection mechanism. The method according to claim 2, wherein the liquid level of the gastrointestinal tract fluid is raised to increase the contact area between the simulated gastrointestinal tract fluid and the drug permeable membrane over time.
4. The vascular chamber is equipped with a mechanism for injecting simulated blood into the inside, and this injection mechanism is used to inject the simulated blood so that the height of the liquid level in the gastrointestinal chamber matches the height of the liquid level in the vascular chamber. The method according to claim 3, wherein the injection is performed into a vascular chamber.
5. The drug concentration in the simulated gastrointestinal tract fluid and / or the drug concentration in the simulated blood is measured over time, and the initial drug concentration increase rate in the simulated gastrointestinal fluid and / or the initial drug concentration increase rate in the simulated blood and the drug in the simulated blood The method according to any one of claims 1 to 4, wherein the oral absorbability of the drug is evaluated by calculating the area under the concentration-time curve.
6. The method according to any one of claims 1 to 5, wherein the state of the simulated gastrointestinal fluid that undergoes changes over time is pH, composition, and volume.
7. It has a gastrointestinal chamber and a vascular chamber, and a simulated gastrointestinal tract chamber is provided at the bottom of the gastrointestinal tract chamber. The drug permeable connection is connected, and the drug permeable membrane is installed so that its surface direction is inclined with respect to the horizontal direction to separate the gastrointestinal tract chamber and the vascular chamber. The gastrointestinal chamber is provided with an inlet for injecting concentrated simulated small intestinal fluid, and the vascular chamber is provided with an inlet for injecting simulated blood inside, and the simulated gastrointestinal fluid contained in the gastrointestinal chamber is agitated. A drug oral absorption evaluation device comprising a stirrer.
8. The seventh aspect of claim 7, further comprising an automatic liquid delivery device for injecting concentrated simulated small intestinal juice from an injection port of a gastrointestinal chamber and / or an automatic liquid delivery device for injecting simulated blood from an injection port of a vascular chamber. Device.
9. (a) A device that automatically samples simulated gastrointestinal fluid and / or simulated blood, (b) A device that automatically samples simulated gastrointestinal fluid and / or simulated blood and automatically applies it to a drug measuring device, or (c) ) The invention according to claim 7 or 8, further comprising an automatic monitoring device that automatically samples simulated gastrointestinal fluid and / or simulated blood, automatically applies it to a drug measuring device, and automatically measures the drug concentration by the drug concentration measuring device. Device.
10. The device according to any one of claims 7 to 9, further comprising a temperature control device capable of keeping at least the temperature of the simulated gastrointestinal fluid in the gastrointestinal chamber and / or the temperature of the simulated blood in the vascular chamber constant.

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