A method for detecting a transdermal diffusion solution of a polythienimide transdermal preparation by ultraviolet spectrophotometry

Abstract

The present application relates to the technical field of pharmaceutical analysis and detection, in particular to a UV spectrophotometric detection method for transdermal diffusion solution of polatynod transdermal preparation. The polatynod structure contains 3,5-dichloro-4-hydroxybenzoyl and benzothiazole sulfone ring, and the UV absorption is generated by the synergistic effect of conjugated system and auxiliary chromophore. The main absorption is dominated by substituted benzoyl, and the benzothiazole sulfone ring is the second. The intramolecular hydroxyl group is an electron-donating group, and the dichloro and sulfone group are electron-withdrawing groups, forming a push-pull electron effect, so that the characteristic maximum absorption wavelength of polatynod in acetonitrile system is stable at 264 nm. The present application uses acetonitrile as the solvent, measures in a quartz cuvette, and quantitatively detects at a wavelength of 264 nm, which can effectively eliminate the interference of transdermal medium matrix and secondary absorption groups. The method is simple, rapid, specific, low in cost, and suitable for high-throughput rapid determination of polatynod concentration in in vitro transdermal diffusion test.

Description

Technical Field

[0001] This disclosure relates to the field of drug analysis and detection technology, specifically to an ultraviolet spectrophotometric detection method for a transdermal diffusion solution of a dotenord transdermal formulation. Background Technology

[0002] Hyperuricemia is a metabolic disease caused by disordered purine metabolism and abnormal uric acid excretion. Its continuous progression is the core pathological basis for gout. With changes in residents' dietary structure and lifestyle, the global incidence of hyperuricemia and gout is increasing year by year, becoming an important chronic metabolic disease affecting public health. Clinically, there is an urgent need for safe, effective, and well-adhered long-term treatment options. Dotinurad is a highly selective uric acid reabsorption inhibitor that reduces the reabsorption of uric acid by renal tubules by selectively inhibiting the activity of urate transporter 1, thereby efficiently promoting uric acid excretion and achieving a uric acid-lowering effect. It is mainly used for the treatment of hyperuricemia and gout. With its advantages of strong targeting, significant uric acid-lowering effect, and low incidence of adverse reactions, it has become a hot topic in clinical drug and formulation development in this field. In recent years, the development of its transdermal delivery formulation has received increasing attention. Compared to traditional oral formulations, transdermal drug delivery effectively avoids gastrointestinal irritation and the first-pass effect of the liver associated with oral administration. It enables stable and sustained drug release, prolongs the duration of action, and improves patient adherence to long-term medication, providing a new route of administration for the long-term treatment of hyperuricemia and gout. In the development of tenorodex transdermal formulations, in vitro transdermal diffusion assays are a key method for evaluating in vitro permeation behavior and screening formulation formulations and processes. Rapid and accurate detection of drug concentration in the diffusion solution during this assay is crucial for obtaining reliable permeation behavior data and ensuring the efficiency and accuracy of formulation development. This places high demands on the specificity, anti-interference ability, detection speed, and batch testing suitability of the detection method.

[0003] Currently, the main technology for content detection of dotenord relies on high-performance liquid chromatography (HPLC). While this method offers good accuracy and resolution, it suffers from inherent drawbacks such as expensive equipment, cumbersome operation, long single-sample testing cycle, high operating and maintenance costs, and unsuitability for rapid screening of large batches of samples. It fails to meet the rapid detection needs of large quantities of diffusion fluid samples in transdermal formulation development, significantly limiting the efficiency of formulation screening and process optimization. Conventional ultraviolet spectrophotometry, with its advantages of simple and rapid operation, widespread instrument availability, low cost, and ability to simultaneously detect large batches of samples, is a commonly used technique for content detection in drug formulation development. However, applying conventional ultraviolet spectrophotometry to the detection of dotenord transdermal diffusion fluid samples presents several unavoidable technical limitations.

[0004] The molecular structure of dotenorode contains two types of groups with UV absorption characteristics: substituted benzoyl groups and benzothiazole sulfone rings. The UV absorption peaks of these two types of groups tend to overlap, resulting in poor specificity of conventional detection methods and making it difficult to achieve specific identification of the target analyte. Existing conventional detection methods lack a basis for selecting characteristic detection wavelengths based on the electronic effects of the dotenorode molecular structure. The selection of detection wavelengths is not targeted and is easily affected by background matrices such as excipients and transdermal accelerators in the transdermal diffusion solution. At the same time, various excipients and transdermal accelerators contained in the transdermal diffusion solution sample can directly affect the stability and accuracy of the detection results, resulting in large errors in direct sample determination. This makes it impossible to provide accurate and reliable content data support for the development of dotenorode transdermal formulations.

[0005] In summary, existing dotenorode detection technologies cannot simultaneously achieve high specificity, strong resistance to interference, ease of operation, and suitability for batch testing. They fail to meet the practical needs for rapid and accurate detection of transdermal diffusion fluid samples during the development of dotenorode transdermal formulations. Therefore, developing a UV detection method based on the molecular structure characteristics of dotenorode, with strong specificity, excellent resistance to matrix interference, ease of operation, and applicability to transdermal diffusion fluid samples is of significant practical value and real-world importance.

[0006] Furthermore, on the one hand, there are differences in understanding among those skilled in the art; on the other hand, the inventors studied a large number of documents and patents when making this invention, but due to space limitations, not all details and contents were listed in detail. However, this does not mean that the present invention does not possess the features of these prior art. On the contrary, the present invention already possesses all the features of the prior art, and the applicant reserves the right to add relevant prior art to the background art. Summary of the Invention

[0007] This disclosure relates to the field of drug analysis and detection technology, specifically to an ultraviolet spectrophotometric detection method for a transdermal diffusion solution of a dotenord transdermal formulation.

[0008] To address the aforementioned technical problems, one objective of this invention is to provide a UV spectrophotometric detection method for a transdermal diffusion solution of a tenorodex transdermal formulation, comprising the following steps: (1) Take the dotenord transdermal diffusion solution, dilute or make up to volume with acetonitrile to prepare the test solution; (2) Using acetonitrile as a blank reference, ultraviolet spectroscopy was performed; (3) Select 264 nm as the quantitative detection wavelength, measure the absorbance and substitute it into the standard curve to calculate the concentration of dotenord.

[0009] According to a preferred embodiment, the standard curve is: with concentration x as the abscissa and absorbance A as the ordinate, : A = 0.021x + 0.0217 Where X is the concentration of dotenord, in μg / mL; and A is the absorbance, in nm.

[0010] According to a preferred embodiment, the standard curve is prepared based on the absorbance of dotenord samples dissolved in acetonitrile at concentrations of 10, 20, 30, 40, 50, 60, 70, 80, 90, and 100 μg / mL.

[0011] According to a preferred embodiment, the acetonitrile is of analytical grade.

[0012] According to a preferred embodiment, the purity of the dotenord sample is not less than 98%.

[0013] According to a preferred embodiment, ultraviolet detection uses a quartz cuvette to hold the sample. Preferably, the cuvette has a diameter of 1 cm.

[0014] According to a preferred embodiment, the temperature required for ultraviolet detection is 15-30°C.

[0015] According to a preferred embodiment, the dotenord transdermal diffusion solution is mixed with acetonitrile at a volume ratio of 1:10.

[0016] One of the objectives of this invention is to provide the use of the above-mentioned detection method in the quality monitoring of transdermal diffusion solutions of dotenord transdermal formulations.

[0017] According to a preferred embodiment, the detection precision is less than 2%.

[0018] According to a preferred embodiment, the recovery rate of the sample is between 95.0% and 105.0%.

[0019] This invention confirms through structural and spectral correlation studies that the ultraviolet absorption of dotenord is generated by the synergistic effect of the conjugated system and auxochrome; the absorption intensity is mainly dominated by the 3,5-dichloro-4-hydroxybenzoyl group, with the benzothiazole sulfone ring contributing secondarily; the 4-hydroxy group (electron-donating) on ​​the benzene ring forms an intramolecular electron-donating and electron-pulling effect with the 3,5-dichloro and sulfone groups (electron-pulling), which makes the maximum absorption wavelength of dotenord in acetonitrile stable at 264 nm.

[0020] This invention selects 264 nm as the quantitative wavelength, which can effectively eliminate the interference of weak absorption from the transdermal matrix and benzothiazole sulfone ring, and achieve highly specific quantitative detection of dotenord.

[0021] The relevant experimental results show that this technical solution has the following beneficial effects: (1) Clear Spectroscopic Mechanism: The selection of the quantitative detection wavelength in this method is supported by a clear and complete spectroscopic and molecular interaction mechanism. Based on the push-pull electron effect formed by the substituted benzoyl group and benzothiazole sulfone ring within the dotenord molecule, the electronic transition characteristics and UV absorption contribution of different chromophores within the molecule were systematically analyzed. Through experimental verification, 264 nm was determined to be the exclusive quantitative wavelength for dotenord. This wavelength precisely corresponds to the characteristic absorption of the electronic transition of the characteristic functional group of dotenord. This is not an empirical screening result, which solves the problem of existing conventional UV detection methods lacking clear wavelength selection criteria and insufficient detection specificity, and provides a solid theoretical foundation for the stability and reliability of the method.

[0022] (2) High specificity: This method possesses excellent detection specificity through precise control of a dedicated quantitative wavelength. It can effectively avoid the overlapping interference of absorption peaks of intramolecular excipients in dotenord, and at the same time, it can effectively eliminate spectral interference from background components such as commonly used excipients, transdermal enhancers, and drug delivery matrices in transdermal diffusion solutions. At the dedicated quantitative wavelength of 264 nm, the above-mentioned interfering components have no obvious UV absorption response, and only the dotenord target analyte exhibits characteristic absorption. Even for transdermal diffusion solution samples that have not undergone complex purification treatment, it can effectively reduce the detection bias caused by matrix effects, ensure the specificity and accuracy of the detection results, and make up for the shortcomings of existing conventional UV detection methods, such as easy overlap of absorption peaks, poor specificity, and susceptibility to matrix interference.

[0023] (3) Fast and simple: The detection process of this method is simple and fast. The sample pretreatment steps are simple and do not require complicated extraction, solid phase extraction, derivatization and other processing procedures. Only simple dilution and volume adjustment of the transdermal diffusion fluid sample are required before it can be directly tested. This greatly simplifies the operation process and reduces the human error introduced by the pretreatment process. The detection cycle of this method is short. It only takes tens of seconds to complete the quantitative detection of a single sample. It can also be adapted to the multi-well plate detection mode and supports the simultaneous detection of a large number of samples. It perfectly meets the high-throughput detection needs of different formulation screening and multi-time point sampling in the development of transdermal preparations. It significantly improves the detection efficiency and solves the problems of the existing high performance liquid chromatography detection process being cumbersome, time-consuming and difficult to adapt to the rapid screening of large numbers of samples. Attached Figure Description

[0024] Figure 1 The standard curve for dotenord is measured at 264 nm using a UV spectrophotometer. Detailed Implementation

[0025] In the description of this invention, terminology is used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly defined.

[0026] Unless otherwise specified, the experimental methods used in the following examples are all conventional methods; the materials, reagents or instruments used, unless otherwise specified by the manufacturer, are all commercially available reagents and materials; the conditions not specified in the examples are all carried out according to conventional conditions or conditions recommended by the manufacturer. At the same time, the present invention does not limit the source of the raw materials used. Unless otherwise specified, the raw materials used in the present invention are all commercially available products in this technical field.

[0027] Example 1 1. Instruments and Reagents UV-Vis spectrophotometer; 1 cm quartz cuvette; acetonitrile (chromatographic grade); dotenord reference standard (purity ≥98%); dotenord transdermal diffusion receiving solution sample.

[0028] 2. Preparation of reference solution Accurately weigh an appropriate amount of dotenord reference standard, dissolve it in acetonitrile and dilute to volume to prepare a series of standard solutions with concentrations of 10, 20, 30, 40, 50, 60, 70, 80, 90 and 100 μg / mL.

[0029] 3. Preparation of the test solution Accurately measure 1.0 mL of the transdermal diffusion solution and place it in a 10 mL volumetric flask. Dilute to the mark with acetonitrile and shake well to obtain the final product.

[0030] 4. Ultraviolet detection conditions Blank reference: Acetonitrile.

[0031] Cuvette: 1 cm quartz.

[0032] Detection wavelength: 264 nm.

[0033] Measurement environment: room temperature.

[0034] 5. Linear relationship Plotting concentration x on the x-axis and absorbance A on the y-axis, a linear regression was performed, such as... Figure 1 As shown, the regression equation is obtained: A = 0.021x + 0.0217 (R) 2 =0.999).

[0035] The results showed that dotenorode exhibited good linearity in the range of 0–100 μg / mL.

[0036] 6. Specificity test A blank transdermal diffusion solution was taken, diluted in the same manner, and measured at 264 nm. The results showed no obvious absorption and no interference with the measurement.

[0037] 7. Precision and Recovery Rate The precision RSD was <2.0%; the recovery rate was between 95.0% and 105.0%. The results show that the detection method involved in this embodiment is accurate and reliable, and can be directly used for the quantification and qualitative analysis of dotenord transdermal diffusion receiving fluid samples.

[0038] It should be noted that the specific embodiments described above are exemplary, and those skilled in the art can devise various solutions inspired by the disclosure of this invention. These solutions all fall within the scope of this invention and its protection. Those skilled in the art should understand that this specification and its accompanying drawings are illustrative and not intended to limit the scope of the claims. The scope of protection of this invention is defined by the claims and their equivalents.

Claims

1. A UV spectrophotometric method for detecting the transdermal diffusion solution of a tenorodex transdermal formulation, characterized in that, Includes the following steps: (1) Take the dotenord transdermal diffusion solution, dilute or make up to volume with acetonitrile to prepare the test solution; (2) Using acetonitrile as a blank reference, ultraviolet spectroscopy was performed; (3) Select 264 nm as the quantitative detection wavelength, measure the absorbance and substitute it into the standard curve to calculate the concentration of dotenord.

2. The ultraviolet spectrophotometric detection method according to claim 1, characterized in that, The standard curve is defined as follows: with concentration x on the x-axis and absorbance A on the y-axis: A = 0.021x + 0.0217 Where X is the concentration of dotenord, in μg / mL; and A is the absorbance, in nm.

3. The ultraviolet spectrophotometric detection method according to claim 2, characterized in that, The standard curves were prepared based on the absorbance of dotenord samples dissolved in acetonitrile at concentrations of 10, 20, 30, 40, 50, 60, 70, 80, 90, and 100 μg / mL.

4. The ultraviolet spectrophotometric detection method according to claim 1, characterized in that, The acetonitrile was of analytical grade.

5. The ultraviolet spectrophotometric detection method according to claim 3, characterized in that, The purity of the dotenord sample is not less than 98%.

6. The ultraviolet spectrophotometric detection method according to claim 1, characterized in that, The dotenord transdermal diffusion solution was mixed with acetonitrile at a volume ratio of 1:

10.

7. The method according to claim 5, characterized in that, The temperature required for ultraviolet detection is 15-30℃.

8. The use of the ultraviolet spectrophotometric detection method for the transdermal diffusion solution of dotenorode transdermal formulations according to any one of claims 1-7 in the quality monitoring of the transdermal diffusion solution of dotenorode transdermal formulations.

9. The use according to claim 8, characterized in that, The precision of the test is less than 2%.

10. The use according to claim 8, characterized in that, The recovery rate of the sample was between 95.0% and 105.0%.

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