Spectrophotometric and spectrofluorimetric studies on azilsartan medoxomil and chlorthalidone to be utilized in their determination in pharmaceuticals

Exploration of 1, 2-naphthoquinone-4-sulfonate derivatizing reagent for determination of chlorthalidone in tablets: a spectrophotometric investigation

Background

Chlorthalidone is a diuretic medicinal agent used to treat hypertension. Lowering hypertension results in the prevention of strokes, heart attacks and kidney-related problems.

Results

In this work, the spectrophotometric investigation was employed to examine the reaction between chlorthalidone and 1, 2-naphthoquinone-4-sulfonate. A reaction is performed at the alkaline environment (pH 9.2) and heated at a moderate temperature of 60 ± 1 °C using a water bath. The red colour product was produced, and it displayed a maximum absorbance at 440.50 nm. Further, the advancement of response conditions was explored by UV/visible spectrophotometer. The stoichiometric of the reaction was considered by using Job’s plot and the reaction mechanism of the proposed work was drawn. The established approach obeyed the calibration curve in the concentration range of 2–12 μg/mL with a regression coefficient superior to 0.994. The accuracy of the method, assessed by employing the % recovery, was in the range of 99.06–99.60% with the % relative standard deviation being less than 2%. The limit of detection and limit of quantification were 0.58 μg/mL and 1.72 μg/mL, respectively.

Conclusion

A UV/visible spectrophotometric investigation for the analysis of the chlorthalidone in the tablet matrix was successfully established and validated. The established investigation was found to be simple and accurate, and because of its ease of use, the proposed strategy could be applied for quality control investigation of chlorthalidone in pharmaceutical matrices.

Full spectrum and genetic algorithm-selected spectrum-based chemometric methods for simultaneous determination of azilsartan medoxomil, chlorthalidone, and azilsartan: Development, validation, and application on commercial dosage form

Five various chemometric methods were established for the simultaneous determination of azilsartan medoxomil (AZM) and chlorthalidone in the presence of azilsartan which is the core impurity of AZM. The full spectrum-based chemometric techniques, namely partial least squares (PLS), principal component regression, and artificial neural networks (ANN), were among the applied methods. Besides, the ANN and PLS were the other two methods that were extended by genetic algorithm procedure (GA-PLS and GA-ANN) as a wavelength selection procedure. The models were developed by applying a multilevel multifactor experimental design. The predictive power of the suggested models was evaluated through a validation set containing nine mixtures with different ratios of the three analytes. For the analysis of Edarbyclor® tablets, all the proposed procedures were applied and the best results were achieved in the case of ANN, GA-ANN, and GA-PLS methods. The findings of the three methods were revealed as the quantitative tool for the analysis of the three components without any intrusion from the co-formulated excipient and without prior separation procedures. Moreover, the GA impact on strengthening the predictive power of ANN- and PLS-based models was also highlighted.

A Versatile Stability-indicating Liquid Chromatographic Method for the Simultaneous Determination of Atenolol, Hydrochlorothiazide and Chlorthalidone

Background:

Atenolol is a selective beta 1 blocker that can be used alone or in combination with hydrochlorothiazide or with chlorthalidone for the treatment of hypertension and prevention from a heart attack.

Objective:

The main target of this work was to improve modern, easy, accurate and selective liquid chromatographic method (RP-HPLC) for the determination of these drugs in the presence of their degradation products. These methods can be used as analytical gadgets in quality control laboratories for a routine examination.

Methods:

In this method, the separation was accomplished through an Inertsil® ODS-3V C18 column (250 mm x 4.6 mm, 5 μm), the mobile phase used was 25 mM aqueous potassium dihydrogen orthophosphate solution adjusted to pH 6.8 by using 0.1M sodium hydroxide and acetonitrile (77 : 23, v/v), the flow rate used was 1 ml/min and detection was achieved at 235 nm using UV.

Results:

All peaks were sharp and well separated, the retention times were atenolol degradation (ATN Deg.) 2.311 min, atenolol (ATN) 2.580 min, hydrochlorothiazide degradation (HCT Deg.) 5.890 min, hydrochlorothiazide (HCT) 7.016 min, chlorthalidone degradation CTD Deg 8.018 min and chlorthalidone (CTD) 14.972 min. Linearity was obtained and the range of concentrations was 20- 160 μg/ml for atenolol, 10-80 μg/ml for hydrochlorothiazide and 10-80 μg/ml for chlorthalidone. According to ICH guidelines, method validation was accomplished, these methods include linearity, accuracy, selectivity, precision and robustness.

Conclusion:

The optimized method demonstrated to be specific, robust and accurate for the quality control of the cited drugs in pharmaceutical dosage forms.

Azilsartan medoxomil

Azilsartan is used for treatment of the high blood pressure (hypertension). Reducing high blood pressure enables avoid strokes, heart attacks and problems of kidneys. Azilsartan comes under the name angiotensin receptor blocker (ARBs) as a class of drugs. It acts by relaxing blood vessels to make it easier for blood to flow. Azilsartan Medoxomil's a comprehensive profile containing the description, formulae, Elemental Analysis, Uses and application. Furthermore, methods and schemes are outlined for the preparation of the drug substance. The physical properties of the medication include constant of ionization, solubility, X-ray powder diffraction pattern, differential scanning calorimetry, thermal conduct and spectroscopic studies are investigated. The methods employed in bulk medicines and/or in pharmaceutical formulations to analyze the drug substance include spectrophotometric, electrochemical and the chromatographic methods. Other studies on this drug substance include drug stability, Pharmaceutical Applications, Mechanism of Action, Pharmacodynamics, and a Dosing Information are reviewed. At the end of this profile, there are more than sixty references were listed.

Liquid chromatography/tandem mass spectrometry study of forced degradation of azilsartan medoxomil potassium

RATIONALE

Azilsartan medoxomil potassium (AZM) is a new antihypertensive drug introduced in the year 2011. The presence of degradation products not only affects the quality, but also the safety aspects of the drug. Thus, it is essential to develop an efficient analytical method which could be useful to selectively separate and identify the degradation products of azilsartan medoxomil potassium.

METHODS

AZM was subjected to forced degradation under hydrolytic (acid, base and neutral), oxidative, photolytic and thermal stress conditions. Separation of the drug and degradation products was achieved by a liquid chromatography (LC) method using an Acquity UPLC(®) C18 CSH column with mobile phase consisting of 0.02% trifluoroacetic acid and acetonitrile using a gradient method. Identification and characterization of the degradation products was carried out using LC/electrospray ionization quadrupole time-of-flight mass spectrometry (ESI-QTOFMS).

RESULTS

A total of five degradation products (DP 1 to DP 5) were formed under various stress conditions and their structures were proposed with the help of tandem mass spectrometry (MS/MS) experiments and accurate mass data. A common degradation product (DP 4) was observed under all the degradation conditions. DP 1, DP 2 and DP 5 were observed under acid hydrolytic conditions whereas DP 3 was observed under alkaline conditions.

CONCLUSIONS

AZM was found to degrade under hydrolytic, oxidative and photolytic stress conditions. The structures of all the degradation products were proposed. The degradation pathway for the formation of degradation products was also hypothesized. A selective method was developed to quantify the drug in the presence of degradation products which is useful to monitor the quality of AZM.

A Rapid Novel HPLC Method for Estimation of Eight Related Compounds in Azilsartan Kamedoxomil and Identification of Degradation Compounds by Using LC-MS

A novel, rapid, specific and stability-indicating reverse-phase high-performance liquid chromatography method was developed for the quantitative determination of related compounds, obtained from two different synthetic routes and degradation products of Azilsartan kamedoxomil (AZL). The method was developed by using a YMC-Pack pro C18 (150 × 4.6 mm, 3 µm) column with a mobile phase containing a gradient mobile phase combination. The eluted compounds were measured at wavelength 220 nm. The developed method run time was 25 min, within which AZL and its eight impurities were well separated with minimum 3.0 resolution. The drug substance was subjected to stress conditions of hydrolysis (acid, base and water), oxidation, photolysis, sunlight, 75% relative humidity and thermal degradation as per International Conference on Harmonization (ICH) prescribed stress conditions to ascertain the stability-indicating power of the method. Significant degradation was observed during acid, base, peroxide, water hydrolysis and 75% relative humidity studies. The mass balance of AZL was close to 100% in all the stress condition. The developed method was validated as per the ICH guidelines with respect to specificity, linearity, limit of detection, limit of quantification, accuracy, precision and robustness.