Method for determining acid resistance of lansoprazole enteric-coated capsules and application thereof

Abstract

The application belongs to the technical field of pharmaceutical analysis, and particularly discloses a method for determining acid resistance of lansoprazole enteric-coated capsules and application thereof.The method for determining acid resistance of lansoprazole enteric-coated capsules first adopts a reciprocating cylinder method to perform acid dissolution on the content of lansoprazole enteric-coated capsules, and then adopts a high performance liquid chromatography method to determine the residual content of lansoprazole in the content after acid resistance; the acid-dissolved acid-resistant medium is an acetate buffer solution containing an anionic surfactant, and the pH value of the acetate buffer solution is 4.5.The acid resistance determination method has strong in-vitro and in-vivo correlation, and can effectively improve the success rate of in-vitro evaluation of bioequivalence of generic drugs and reference preparations.

Description

Technical Field

[0001] This invention belongs to the field of pharmaceutical analysis technology, and in particular relates to a method and application for determining the acid resistance of lansoprazole enteric-coated capsules. Background Technology

[0002] Lansoprazole, developed by Takeda Pharmaceutical Company of Japan, is a first-generation proton pump inhibitor. Its primary absorption site is the small intestine. Lansoprazole is unstable below pH 10, especially under acidic conditions; its stability increases with increasing pH within the range of 1-10. Therefore, lansoprazole is absorbed and degraded simultaneously in vivo. Furthermore, lansoprazole exhibits low solubility and high permeability, making its dissolution rate a major factor influencing its absorption. To address the acid instability of lansoprazole and the gastric irritation of its degradation products, the original manufacturer formulated it as an enteric-coated formulation, primarily for the treatment of gastric ulcers, duodenal ulcers, anastomotic ulcers, and reflux esophagitis.

[0003] To improve the success rate of in vitro bioequivalence assessments between generic and reference formulations, establishing an assessment method with in vitro-in vivo correlation is crucial. Based on the properties of lansoprazole, it is particularly important that the acid resistance of the generic drug is comparable to that of the reference formulation.

[0004] Practical application has revealed that the acid resistance methods used in various pharmacopoeias for lansoprazole enteric-coated capsules do not show strong correlation with in vivo absorption. Therefore, there is an urgent need to develop a method for determining the acid resistance of lansoprazole enteric-coated capsules that exhibits stronger in vitro and in vivo correlation. Summary of the Invention

[0005] The present invention aims to at least solve one of the technical problems existing in the prior art. To this end, the present invention proposes a method and application for determining the acid resistance of lansoprazole enteric-coated capsules. This acid resistance determination method has strong in vitro-in vivo correlation and can effectively improve the success rate of in vitro bioequivalence assessment of generic drugs and reference preparations.

[0006] To solve the above-mentioned technical problems, the first aspect of the present invention provides a method for determining the acid resistance of lansoprazole enteric-coated capsules, wherein the contents of the lansoprazole enteric-coated capsules are first acid-dissolved using a reciprocating cylinder method, and then the remaining content of lansoprazole in the acid-resistant contents is determined by high performance liquid chromatography.

[0007] The acid-resistant medium for acid dissolution is an acetate buffer containing an anionic surfactant, and the pH value of the acetate buffer is 4.5.

[0008] Preferably, the anionic surfactant is sodium dodecyl sulfate (SDS).

[0009] Preferably, the concentration of the anionic surfactant is 0.003-0.15 wt%; more preferably, the concentration of the anionic surfactant is 0.008-0.12 wt%. Studies have found that: if the concentration of the anionic surfactant is too low, the destructive power is weak, and the contents of the lansoprazole pellets remain intact, making it impossible to distinguish the acid resistance of the self-developed pellets and the reference pellets; if the concentration of the anionic surfactant is too high, both the self-developed pellets and the reference pellets from different process formulations break, making it impossible to distinguish the acid resistance of samples from different formulations.

[0010] As a further improvement to the above scheme, the method for determining the acid resistance of lansoprazole enteric-coated capsules includes the following steps:

[0011] (1) Take the contents of lansoprazole enteric-coated capsules, place them in a reciprocating cylinder, use acetate buffer containing anionic surfactant as the acid-resistant medium, and use the reciprocating cylinder method to acid dissolve the contents to obtain acid-resistant contents; then dissolve the acid-resistant contents to obtain the test solution.

[0012] (2) The residual content of lansoprazole in the test solution was determined by high performance liquid chromatography.

[0013] As a further improvement to the above scheme, the preparation process of the test solution is as follows:

[0014] The reciprocating cylinder undergoes a first reciprocating motion in an acid-resistant medium, rises above the liquid surface, and is filtered dry; then the reciprocating cylinder undergoes a second reciprocating motion in the acid-resistant medium, rises above the liquid surface; then the reciprocating cylinder is transferred to a mixed solution containing an alkaline solution and a phosphate buffer solution, undergoes a third reciprocating motion, the solution is filtered, and the test sample solution is obtained.

[0015] Preferably, the reciprocating frequencies of the first reciprocating motion, the second reciprocating motion, and the third reciprocating motion are all 20-30 times / minute.

[0016] Preferably, the duration of the first reciprocating motion is 40-60 minutes.

[0017] Preferably, the second reciprocating motion takes 15-20 minutes.

[0018] Preferably, the duration of the third reciprocating motion is 10-50 minutes.

[0019] Preferably, the pH value of the mixed solution is greater than 10. This mixed solution is mainly used to dissolve the contents after acid resistance. When the pH value is greater than 10, the stability of the dissolution can be guaranteed.

[0020] More preferably, the alkaline solution is 10 mL of a 1 mol / L NaOH solution, the phosphate buffer solution has a pH of 6.8, and the volume of the mixed solution is 200-250 mL.

[0021] As a further improvement to the above scheme, the chromatographic conditions of the high performance liquid chromatography method are as follows: the chromatographic column is packed with octadecyl bonded silica gel, the mobile phase includes methanol, water, triethylamine and phosphoric acid, the wavelength is 284 nm, the flow rate is 1.0 mL / min, the column temperature is 30 °C, and the injection volume is 10 μL.

[0022] Preferably, the chromatographic column is a Welch Ultimate C18 (4.6 mm × 150 mm, 3 μm).

[0023] Preferably, the volume ratio of methanol, water, triethylamine and phosphoric acid in the mobile phase is 600:400:5:1.5, and the pH of the mobile phase is adjusted to 7.3 using phosphoric acid.

[0024] A second aspect of the present invention provides a method for determining the acid resistance of lansoprazole enteric-coated capsules and its application in pharmaceutical analysis.

[0025] Compared with the prior art, the above-described technical solution of the present invention has at least the following technical effects or advantages:

[0026] (1) The enteric coating material of lansoprazole enteric-coated capsules is an aqueous dispersion of methacrylic acid-ethyl acrylate copolymer. This material is pH sensitive and insoluble in acid. Theoretically, it can dissolve in media with a pH above 5.5. At a normal enteric coating thickness, the coating can slowly dissolve when a certain concentration of salt ions is added at the critical pH value. However, the acid-resistant media used in the acid resistance methods of existing pharmacopoeias (such as 0.1 mol / L hydrochloric acid solution) are far from the critical pH value and have low ion concentrations, resulting in weak destructive strength and difficulty in dissolving the enteric coating. The acid resistance of different samples is very weak, leading to a weak correlation with in vivo absorption. This invention uses a pH 4.5 acetate buffer containing anionic surfactant as the acid-resistant medium, which can better dissolve the enteric coating and has a stronger correlation with in vivo absorption.

[0027] (2) Compared with the basket method in the Chinese Pharmacopoeia and the paddle method in the United States Pharmacopoeia and the British Pharmacopoeia, the present invention uses the reciprocating cylinder method to acid dissolve lansoprazole. The reciprocating cylinder has a smaller medium volume and is closer to the volume of human gastric juice. In addition, with a specific acid-resistant medium, it can better fit the compactness of the contents of lansoprazole pellets and the toughness of the enteric coating, thereby further improving the in vitro-in vivo correlation of the determination. Detailed Implementation

[0028] The present invention will now be described in detail with reference to embodiments to facilitate understanding of the invention by those skilled in the art. It is particularly important to note that the embodiments are merely illustrative of the invention and should not be construed as limiting the scope of protection of the invention. Non-essential improvements and adjustments made to the invention by those skilled in the art based on the above description should still fall within the scope of protection of the present invention.

[0029] Example 1

[0030] A method for determining the acid resistance of lansoprazole enteric-coated capsules includes the following steps:

[0031] (1) Discard the outer shell of the lansoprazole enteric-coated capsule, take its contents, place them in a reciprocating cylinder, and use a pH 4.5 acetate buffer containing 0.1 wt% SDS as the acid-resistant medium. After the reciprocating cylinder undergoes the first reciprocating motion (reciprocating frequency of 25 times / minute) in the acid-resistant medium for 50 minutes, it rises out of the liquid surface and the acid-resistant medium is filtered dry. Then the reciprocating cylinder undergoes the second reciprocating motion (reciprocating frequency of 25 times / minute) in the acid-resistant medium for 15 minutes and rises out of the liquid surface. Then the reciprocating cylinder is transferred to a mixed solution containing 10 mL of 1 mol / L NaOH solution and 250 mL of pH 6.8 phosphate buffer solution, and undergoes the third reciprocating motion (reciprocating frequency of 30 times / minute) for 30 minutes. The mixed solution is filtered to obtain the test solution.

[0032] (2) The remaining content of lansoprazole in the test solution prepared in step (1) was determined by HPLC, that is, the remaining content of lansoprazole in the contents of the acid-resistant pills.

[0033] The chromatographic conditions for the HPLC method are as follows:

[0034] Chromatographic column: Welch Ultimate C18 (4.6 mm × 150 mm, 3 μm) with octadecyl bonded silica gel as the packing material;

[0035] Mobile phase: methanol-water-triethylamine-phosphoric acid in a volume ratio of 600:400:5:1.5, with the pH adjusted to 7.3 using phosphoric acid;

[0036] Wavelength: 284nm;

[0037] Flow rate: 1.0 mL / min;

[0038] Column temperature: 30℃

[0039] Injection volume: 10 μL.

[0040] The residual lansoprazole content in the acid-resistant capsules of three self-developed lansoprazole capsules and the original lansoprazole capsules was determined using the above method. These were named Self-developed 001, Self-developed 002, Self-developed 003, and Reference Formulation, respectively. The results are shown in Table 1. Among them: Postprandial AUC 0-t The area under the blood drug concentration-time curve is directly proportional to the total amount of drug absorbed and represents the degree of drug absorption. The data comes from human bioequivalence studies, i.e., in vivo studies; N / A indicates not applicable.

[0041] Table 1:

[0042]

[0043] Table 1 shows that the results of the in vitro acid resistance test method in Example 1 (ratio of self-developed content to reference content) and the results of the in vivo acid resistance test method (postprandial AUC of self-developed content to reference content) are comparable. 0-t The ratios show a good correlation.

[0044] Example 2

[0045] A method for determining the acid resistance of lansoprazole enteric-coated capsules includes the following steps:

[0046] (1) Discard the outer shell of the lansoprazole enteric-coated capsule, take its contents, place it in a reciprocating cylinder, and use a pH 4.5 acetate buffer containing 0.1 wt% SDS as the acid-resistant medium. After the reciprocating cylinder undergoes the first reciprocating motion (reciprocating frequency of 25 times / minute) in the acid-resistant medium for 60 minutes, it is raised out of the liquid surface and the acid-resistant medium is filtered dry. Then, the reciprocating cylinder undergoes the second reciprocating motion (reciprocating frequency of 25 times / minute) in the acid-resistant medium for 20 minutes, and is raised out of the liquid surface again. Then, the reciprocating cylinder is transferred to a mixed solution containing 10 mL of 1 mol / L NaOH solution and 250 mL of pH 6.8 phosphate buffer solution, and undergoes the third reciprocating motion (reciprocating frequency of 30 times / minute) for 10 minutes. The mixed solution is filtered to obtain the test solution.

[0047] (2) The remaining content of lansoprazole in the test solution prepared in step (1) was determined by HPLC, that is, the remaining content of lansoprazole in the contents of the acid-resistant pills.

[0048] The chromatographic conditions for the HPLC method were the same as in Example 1.

[0049] The residual lansoprazole content in the acid-resistant pills of three self-developed lansoprazole capsules and the original lansoprazole capsules was determined using the above method. They were named self-developed 001, self-developed 002, self-developed 003 and reference preparation, respectively. The results are shown in Table 2.

[0050] Table 2:

[0051]

[0052]

[0053] Table 2 shows that the results of the in vitro acid resistance test method in Example 2 (ratio of self-developed content to reference content) and the results of the in vivo acid resistance test method (postprandial AUC of self-developed content to reference content) are comparable. 0-t The ratios show a good correlation.

[0054] Example 3

[0055] The only difference between Example 3 and Example 2 is that in step (1), the time for the first reciprocating motion is 30 minutes.

[0056] The residual lansoprazole content in the acid-resistant pills of three self-developed lansoprazole capsules and the original lansoprazole capsules was determined using the method in Example 3. They were named self-developed 001, self-developed 002, self-developed 003 and reference preparation, respectively. The determination results are shown in Table 3.

[0057] Table 3:

[0058]

[0059] As shown in Table 3, when the dynamic strength in the acid resistance test method is insufficient, the morphology of each batch of samples remains relatively intact, the main components dissolve less, the method has weak distinguishing power for each sample, and the results of the in vitro acid resistance test method have poor correlation with the in vivo postprandial AUC0-t results.

[0060] Example 4

[0061] The only difference between Example 4 and Example 2 is that in step (1), the time for the second reciprocating motion is 35 minutes.

[0062] The residual lansoprazole content in the acid-resistant pills of three self-developed lansoprazole capsules and the original lansoprazole capsules was determined using the method in Example 4. They were named self-developed 001, self-developed 002, self-developed 003 and reference preparation, respectively. The results are shown in Table 4.

[0063] Table 4:

[0064]

[0065]

[0066] As shown in Table 4, when the dynamic intensity in the acid resistance test method is too high, all batches of sample pellets are broken, the main components are degraded, the color tends to be uniform, the method has weak discrimination ability for each sample, and the results of the in vitro acid resistance test method have poor correlation with the in vivo postprandial AUC0-t results.

[0067] Example 5

[0068] The only difference between Example 5 and Example 1 is that in step (1), the concentration of SDS is 0.2 wt%.

[0069] The residual lansoprazole content in the acid-resistant pills of three self-developed lansoprazole capsules and the original lansoprazole capsules was determined using the method in Example 5. They were named self-developed 001, self-developed 002, self-developed 003 and reference preparation, respectively. The results are shown in Table 5.

[0070] Table 5:

[0071]

[0072] Table 5 shows that when the SDS concentration is too high, both the self-developed pills and the reference pills from different process formulations break down to similar degrees, indicating that the method has weak distinguishing power among the samples. The results of the in vitro acid resistance test are inconsistent with the in vivo postprandial AUC. 0-t The results showed poor correlation.

[0073] Comparative Example 1

[0074] The dissolution and release rate determination was performed according to the method in the Chinese Pharmacopoeia (General Rule 0931, Method 1, Rotating Basket Method). The specific steps are as follows:

[0075] Take the contents of lansoprazole enteric-coated capsules and dissolve them in 1000 mL of 0.1 mol / L hydrochloric acid solution at 100 rpm. After 120 minutes, remove the rotating basket and flush the microparticles to the bottom of the basket with acid, removing as many microparticles as possible that are stuck to the basket. Add 5 mL of 0.1 mol / L sodium hydroxide solution to a 100 mL brown volumetric flask and place a funnel on top. Invert the rotating basket into the funnel and flush the microparticles into the volumetric flask with 20 mL of water. Add about 30 mL of methanol and shake for 20 minutes. Dilute to the mark with 60% methanol-water solution, shake well, filter, and use the filtrate as the test solution. Determine the remaining lansoprazole content in the capsules after acid resistance using HPLC.

[0076] The chromatographic conditions for the HPLC method were the same as in Example 1.

[0077] The residual lansoprazole content in the acid-resistant pills of three self-developed lansoprazole capsules and the original lansoprazole capsules was determined using the above method. They were named self-developed 001, self-developed 002, self-developed 003 and reference preparation, respectively. The results are shown in Table 6.

[0078] Table 6:

[0079]

[0080] Table 6 shows that the results of the in vitro acid resistance determination method according to the Chinese Pharmacopoeia (ratio of self-developed to reference content) and the results of the in vivo acid resistance determination method (postprandial AUC of self-developed and reference content) are comparable. 0-t The correlation between the ratios is poor.

[0081] Comparative Example 2

[0082] The dissolution and release determination was performed according to the United States Pharmacopeia method (General Rule 0931, Method II, Paddle Method), with the following specific steps:

[0083] Take lansoprazole enteric-coated capsules and use 500 mL of 0.1 mol / L hydrochloric acid solution as the dissolution medium. The dissolution speed is 75 rpm. After 60 minutes, take 25 mL of the sample, filter it, and determine the amount of lansoprazole dissolved in the dissolution medium by ultraviolet-visible spectrophotometry.

[0084] The conditions for ultraviolet-visible spectrophotometry are as follows:

[0085] Detection wavelength: 306nm;

[0086] Cuvette: 5cm.

[0087] The residual lansoprazole content in the acid-resistant pills of the three self-developed lansoprazole capsules and the original lansoprazole capsules was determined by the above method. They were named self-developed 001, self-developed 002, self-developed 003 and reference preparation, respectively. The results are shown in Table 7.

[0088] Table 7:

[0089]

[0090] Table 7 shows that the results of the in vitro acid resistance test using the United States Pharmacopeia method (ratio of self-developed to reference content) and the results of the in vivo acid resistance test using the in vivo method (postprandial AUC of self-developed and reference content) are comparable. 0-t The correlation between the ratios is poor.

[0091] Comparative Example 3

[0092] The dissolution and release determination was performed according to the British Pharmacopoeia method (General Rule 0931, Method II, Paddle Method), with the following specific steps:

[0093] Take the contents of lansoprazole enteric-coated capsules and dissolve them in 700 mL of pH 4.5 phosphate buffer at 150 rpm. After 45 minutes, take a 7 mL sample, filter, and take 5 mL of the filtrate. Dilute to 25 mL with solution A (a mixture of 11 volumes of 0.25 mol / L Na3PO4 solution and 22 volumes of 0.5 mol / L anhydrous Na2HPO4 solution, diluted with water to 100 volumes, and adjusted to pH 11 with phosphoric acid or 10 mol / L sodium hydroxide solution if necessary). Mix well to obtain the test solution. Determine the amount of lansoprazole dissolved in the dissolution medium using HPLC.

[0094] The chromatographic conditions for the HPLC method were the same as in Example 1.

[0095] The residual lansoprazole content in the acid-resistant pills of three self-developed lansoprazole capsules and the original lansoprazole capsules was determined using the above method. They were named self-developed 001, self-developed 002, self-developed 003 and reference preparation, respectively. The results are shown in Table 8.

[0096] Table 8:

[0097]

[0098] Table 8 shows that the results of the in vitro acid resistance test using the British Pharmacopoeia method (ratio of self-developed to reference content) and the results of the in vivo acid resistance test method (postprandial AUC of self-developed and reference content) are comparable. 0-t The correlation between the ratios is poor.

[0099] Comparative Example 4

[0100] Using simulated gastric juice as the acid-resistant medium, the dissolution and release rates were determined according to the method (General Rule 0931, Method 1, rotating basket method). The specific steps are as follows:

[0101] Take the contents of lansoprazole enteric-coated capsules and use 500 mL of USP simulated gastric juice (2 g of sodium chloride and 3.2 g of pepsin were dissolved in 500 mL of water, stirred, and then 7 mL of hydrochloric acid was added and diluted with water to 1 L. Mix well) as the dissolution medium. The rotation speed was 150 rpm. After 60 minutes, remove the rotating basket and use acid to flush the microparticles to the bottom of the basket, trying to flush off as many microparticles as possible that are stuck to the basket. Add 5 mL of 0.1 mol / L sodium hydroxide solution to a 100 mL brown volumetric flask and place a funnel on it. Invert the rotating basket into the funnel and flush the microparticles into the volumetric flask with 20 mL of water. Add about 30 mL of methanol, shake for 20 minutes, dilute to the mark with 60% methanol-water mixture, shake well, filter, and take the filtrate as the test solution. Use HPLC to determine the remaining lansoprazole content in the capsules after acid resistance.

[0102] The chromatographic conditions for the HPLC method were the same as in Example 1.

[0103] The residual lansoprazole content in the acid-resistant pills of the three self-developed lansoprazole capsules and the original lansoprazole capsules was determined using the above method. They were named self-developed 001, self-developed 002, self-developed 003 and reference preparation, respectively. The results are shown in Table 9.

[0104] Table 9:

[0105]

[0106] In this comparative example, after 60 minutes of acid resistance testing, the rotating basket was removed, and the pellets in the basket were observed to be intact and not broken. Combined with the results in Table 9, it can be seen that the results of this in vitro acid resistance test method are consistent with the in vivo postprandial AUC. 0-t The results showed poor correlation and were not applicable to the determination of the acid resistance of lansoprazole enteric-coated capsules.

[0107] Comparative Example 5

[0108] The only difference between Comparative Example 5 and Example 1 is that in step (1), the acid-resistant medium does not contain SDS.

[0109] The residual lansoprazole content in the acid-resistant pills of three self-developed lansoprazole capsules and the original lansoprazole capsules was determined using the method of Comparative Example 5. They were named Self-developed 001, Self-developed 002, Self-developed 003 and Reference Preparation, respectively. The results are shown in Table 10.

[0110] Table 10:

[0111]

[0112] Table 10 shows that when the acid-resistant medium does not contain anionic surfactants, the pellet morphology of each batch of samples remains relatively intact, the main component dissolves less, and the method has weak distinguishing power between samples. The results of the in vitro acid resistance test method are similar to those of the in vivo postprandial AUC. 0-t The results showed poor correlation.

[0113] For those skilled in the art, several simple deductions or substitutions can be made without departing from the inventive concept, without requiring creative effort. Therefore, any simple improvements made to this invention by those skilled in the art based on the disclosure of this invention should be within the scope of protection of this invention. The above embodiments are preferred embodiments of this invention, and all processes similar to this invention and equivalent changes should fall within the scope of protection of this invention.

Claims

1. A method for determining the acid resistance of lansoprazole enteric-coated capsules, characterized in that, Includes the following steps: (1) Take the contents of lansoprazole enteric-coated capsules, place them in a reciprocating cylinder, use acetate buffer containing anionic surfactant as an acid-resistant medium, and use the reciprocating cylinder method to acid dissolve the contents to obtain acid-resistant contents. The acid-resistant contents are then dissolved to obtain the test solution; The acid-resistant medium for acid leaching is an acetate buffer solution containing an anionic surfactant, the pH of which is 4.5; the anionic surfactant is sodium dodecyl sulfate, and its concentration is 0.003-0.15 wt%. The preparation process of the test solution is as follows: the reciprocating cylinder undergoes its first reciprocating motion in an acid-resistant medium, rises above the liquid surface, and is then filtered dry; Then the reciprocating cylinder undergoes a second reciprocating motion in the acid-resistant medium, rising above the liquid surface; then the reciprocating cylinder is transferred to a mixed solution containing an alkaline solution and a phosphate buffer solution, undergoing a third reciprocating motion, and the solution is filtered to obtain the test sample solution; The reciprocating frequencies of the first, second, and third reciprocating movements are all 20-30 times / minute; the duration of the first reciprocating movement is 40-60 minutes, the duration of the second reciprocating movement is 15-20 minutes, and the duration of the third reciprocating movement is 10-50 minutes; the pH value of the mixed solution is greater than 10. (2) The residual content of lansoprazole in the test solution was determined by high performance liquid chromatography.

2. The method for determining the acid resistance of lansoprazole enteric-coated capsules according to claim 1, characterized in that, The chromatographic conditions for the high performance liquid chromatography method are as follows: the column is packed with octadecyl bonded silica gel; the mobile phase includes methanol, water, triethylamine and phosphoric acid; the wavelength is 284 nm; the flow rate is 1.0 mL / min; the column temperature is 30 °C; and the injection volume is 10 μL.

3. The application of the method for determining the acid resistance of lansoprazole enteric-coated capsules according to any one of claims 1 to 2 in pharmaceutical analysis.

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