Sustainable signal processing spectrophotometric analysis of candesartan, hydrochlorothiazide, and amlodipine: Green methods aligned with global sustainability goals

Green Analytical Chemistry (GAC) aims to create eco-friendly methods for pharmaceutical analysis, with a focus on quality control. This study focuses on the simultaneous quantification of candesartan (CAN), hydrochlorothiazide (HCT), and amlodipine (AML) in a triple medication using two green spectrophotometric techniques. The study incorporates mathematical manipulation approaches to extract the parent spectrum of each drug component. These integrated methods address the problem of spectral signal overlap without requiring prior separation, utilizing a factorized spectrum (FS), which is notable for its capacity to assess the specified drugs in the mixture and retrieve their original zero-order spectra it is distinctive for its ability to evaluate the mentioned drugs within the mixture and recover their initial zero-order spectra. The first integrated resolution technique, the Integrated signal processing plan (ISPP-D0), was applied to the mixture's zero-order spectrum, including successive manipulation of three methods: extended absorbance difference, absorbance resolution, and spectrum subtraction. The second integrated resolution technique is the Integrated signal processing plan (ISPP-R)via ratio spectrum of the mixture, which includes successive manipulation of three methods: dual amplitude difference, ratio extraction, and spectrum subtraction. The proposed methods were validated and assessed following the International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use (ICH) guidelines, showing linear concentration ranges of 5.0-35.0 µg/mL for CAN at 254.0 nm, 2.0-20.0 µg/mL for HCT at 270.0 nm, and 5.0-35.0 µg/mL for AML at 240.0 nm. The specificity was evaluated by accurately and precisely determining the concentrations of the three drugs in their synthetic blends and single-tablet pharmaceutical formulation. The findings were statistically analyzed against the official results using the F-test and Student's t-test, indicating no notable differences. These UV spectrophotometric techniques align with green analytical chemistry (GAC) and white analytical chemistry (WAC) principles, supporting the United Nations Sustainable Development Goals (UNSDGs). These integrated analytical techniques for drug analysis offer enhanced precision and efficiency, enabling the retrieval of zero-order spectra that serve as unique fingerprints for each analyte. These advancements simplify the identification process, improve accuracy, and ensure reliable results, making them invaluable in pharmaceutical research and quality control.

The power of High Impact Amplitude Manipulation (HIAM) technique for extracting the basic spectra of two Fixed-dose combinations (FDC) -Spectrophotometric purity analysis via spectral contrast angle

HIAM technique allows the extraction of the original constant signal of each single component out of interference signals of a mixture and further transformed into basic spectrum (D⁰). It includes the methods: ratio subtraction coupled with unified constant subtraction (RS-UCS), constant center (CC) and constant extraction (CE). The technique was introduced for the analysis of two pharmaceutical formulations used to treat cardiovascular diseases. The formulations are binary combinations of Amlodipine (AML) with either Atorvastatin (ATR) or Candesartan (CND) which shows interefernce absorbance signals. The technique was valid over the linearity range of (5.0-35.0 µg/ml) for AML, ATR and CND with recovery percentage 100.40 ± 1.88 , 100.00 ± 0.86 and 99.83 ± 1.07, respectively . The extracted signals were tested for its purity by spectral contrast angle (cos θ) to illustrate the efficency of the HIAM technique where cos θ values ranges from (0.9902 to 0.9986). The presented technique was fully validated regarding ICH guidelines and were statistically compared using one-way ANOVA at 95% confidence.

Reversed-phase high-performance liquid chromatography: A fast and efficient analytical method to quantify docetaxel-loaded pegylated liposomes in release study

Docetaxel is an anticancer that belongs to the family of taxanes and acts in the inhibition of cell proliferation through the polymerization of microtubules. The aim of this study was the development and validation of a fast method by reversed-phase high-performance liquid chromatography for quantitative analysis of docetaxel encapsulated in pegylated liposomes. The analytical method was validated for the following recognized specifications: system suitability, precision (repeatability and intermediate precision), linearity, accuracy, selectivity, detection and quantification limits, and robustness. The reversed phase-high-performance liquid chromatography analyses were performed at a temperature of 45°C (isocratic mode). The mobile phase was composed of acetonitrile and water (65:35, v/v) and the flow rate was fixed at 0.8 mL/min. The running time and wavelength were 8 min and 230 nm, respectively. The method was found to be linear, precise, selective, precise, robust, accurate, in the range of 1-75 μg/mL (R² = 0.9999) and the values of detection and quantification limits were 2.35 and 7.84 μg/mL, respectively. The release rates of docetaxel in pegylated liposomes were lower compared to docetaxel in solution. The reversed phase high-performance liquid chromatography method developed proved to be adequate and can be effectively used to determine the in vitro release profile of docetaxel transported by pegylated liposomes.

A Rapid HPLC Method for the Concurrent Determination of Several Antihypertensive Drugs from Binary and Ternary Formulations

A rapid, synchronized liquid chromatographic method was established for the estimation of hydrochlorothiazide (HCZ), amlodipine (AMD), olmesartan (OLM), telmisartan (TEL), and irbesartan (IRB) in binary and ternary coformulations using the same chromatographic conditions. Five analytes were separated on a Zorbax C18 column using isocratic elution with a mobile phase consisting of acetonitrile, methanol, and 20 mM phosphate buffer (pH 3.5) in a ratio of 45:20:35% v/v. The analytes were detected at a wavelength of 230 nm at ambient temperature. Furthermore, the proposed liquid chromatographic procedure was validated for linearity, precision, accuracy, stability, and robustness using an experimental design. Analytes were separated with good resolution within 3.5 min. Analytes showed good linearity in a concentration satisfactory to analyze the different ratios of these analytes in the formulations. Pareto charts showed that the flow rate and mobile phase composition have a significant effect on the peak area of analytes and hence need to be carefully controlled, however, the method is robust. Finally, the different formulations consisting of HCZ, AMD, OLM, TEL, and IRB in different ratios were analyzed with high accuracy using an optimized HPLC method and compared with reported methods. Furthermore, the reported HPLC procedure is simple, rapid, and accurate and therefore can used for regular quality control of binary and ternary formulations using the same stationary and mobile phase.

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.

Integrated Analytical Quality by Design (AQbD) Approach for the Development and Validation of Bioanalytical Liquid Chromatography Method for Estimation of Valsartan

The present studies describe the systematic development and validation of a simple, rapid, sensitive and cost-effective reversed-phase high-performance liquid chromatographic bioanalytical method for the estimation of valsartan in rat plasma employing analytical quality by design (AQbD) principles quality risk management was applied for identifying the critical method parameters (CMPs) and subsequently method optimization was performed employing Box–Behnken design by selecting mobile phase pH, flow rate and % organic modifier as the CMPs and evaluated for critical analytical attributes (CAAs) such as peak area, retention time, peak tailing and number of theoretical plates. The developed method was then transferred to bioanalysis, where liquid–liquid extraction process was used for separating the drug from rat plasma. The optimization of extraction process was performed with the help of face-centered cubic design by selecting centrifugation speed and centrifugation time as the CMPs for maximizing % recovery, signal-to-noise ratio and purity threshold of the drug peak after extraction as the CAAs. Optimum chromatographic solution was chosen by mathematical and graphical search techniques, and design space was demarcated. Validation studies performed for the developed method indicated linearity ranging between 5 and 100 ng.mL−1, whereas accuracy and precision study showed good percent recovery (99–102%) along with % relative standard deviation within ±2%. Sensitivity evaluation revealed limit of detection and limit of quantification were found to be 0.76 ng.mL−1 and 2.29 ng.mL−1, respectively. In a nutshell, the present work demonstrates significant merits of AQbD approach for holistic process understanding and analytical method development and validation with enhanced robustness and performance.

A Smart Green Spectrophotometric Method for Simultaneous Determination of Severely Overlapped Binary Mixtures Using Normalized Spectrum and Isosbestic Point as Resolving Tools

Background:

The ability of the normalized spectra when used as a divisor and in combination with isosbestic point to resolve complex binary or ternary mixtures, Candesartan and Hydrochlorthiazide binary mixture was taken as a model.

Introduction:

A green simple smart and accurate method using ethanol as a solvent namely simultaneous derivative ratio (SIDD) was applied to prove the power of normalized spectra and isosbestic point as spectrophotometric resolving tools.

Methods:

In the proposed SIDD method, the zero order spectra of drugs were simply manipulated using the normalized spectra of CAN as divisor to obtain the ratio and first derivative spectra in two successive steps. Firstly, the total amplitude at isosbestic point 255.4 nm of the ratio spectra of the mixture was measured representing the total actual concentration of both drugs in the mixture. Then, the first derivative of the ratio spectra was obtained to determine Hydrochlorothiazide concentration at 233 nm. While the concentration of Candesartan was determined subsequently by subtracting the Hydrochlorothiazide concentration calculated after derivatization from the total concentration of both drugs obtained at the ratio spectra before the derivatization step.

Results:

The SIDD was successfully applied for simultaneous determination of both drugs in their pure form or in their binary mixture either in synthetic prepared mixtures or in combined dosage form the adopted method was validated according to the ICH guidelines and the results were found to be within the acceptable limits.

Conclusion:

The adopted method highlighted the important role of normalized spectrum when used as a divisor in addition to the importance of isosbestic point to resolve severely overlapped spectra. All the measurements were carried using ethanol which is considered one of the greenest solvents making the method an environmentally friendly one. the adopted method was validated according to the ICH guidelines and the results were found to be within the acceptable limits.

HPLC method transfer study for simultaneous determination of seven angiotensin II receptor blockers

In this study, a sensitive high-performance liquid chromatography method was developed and validated for the simultaneous determination of seven angiotensin II receptor blockers, namely, hydrochlorothiazide, chlorthalidone, eprosartan mesylate, valsartan, losartan potassium, irbesartan, and candesartan cilexetil. Different chromatographic parameters were tested and fully optimized. Best chromatographic separation was accomplished on a reversed-phase octadecylsilyl column (250 × 4.6 mm id; 5 μm) under gradient elution using methanol/sodium phosphate monobasic buffer (0.01 M, pH 6.5) as mobile phase. The detection of target analytes was obtained at 254 nm. The pH of the buffer has been selected according to Marvin^® sketch software. The proposed method was validated according to ICH guidelines and showed good precision (relative standard deviation < 1), good linearity (square of correlation coefficient ≥ 0.999), and high accuracy (between 98 and 102%) with detection limit and quantitation limit (40 and 160 ng/mL, respectively) for all the detected analytes.

Selective and validated kinetic spectrophotometric method for the determination of irbesartan in pure and pharmaceutical formulations

A novel-coupling reagent is used for the simple and sensitive kinetic spectrophotometric determination of irbesartan (IRB) in pure or pharmaceutical formulations. The method utilizes an oxidative coupling reaction based on oxidation of 3-methyl-2-benzothiazolinone hydrazone hydrochloride monohydrate (MBTH) with Ce(IV) in 2% sulfuric acid medium, followed by coupling the produced electrophilic intermediate (diazonium salt of the reagent) with IRB to give greenish-blue colored product (1:1, stoichiometry) having maximum absorption at 629nm and the colored species is stable for more than 1h. The initial rate and fixed time (at 35min) methods are adopted for determination of IRB concentration. The linearity is in the ranges of 5.0-40.0μg/mL and 2.0-45.0μg/mL and the limit of detection is 0.46 and 0.40μg/mL for initial rate and fixed time methods, respectively. Molar absorptivity for the method was found to be 1.50×10⁴L/molcm. The validated kinetic methods can be successfully applied to the analysis of IRB in bulk and tablet dosage form and in the routine quality control analysis. The percentage recoveries were above 100% for both methods. The excipients did not interfere in the analysis.