RP-LC and HPTLC Methods for the Determination of Olmesartan Medoxomil and Hydrochlorothiazide in Combined Tablet Dosage Forms

An investigative review for pharmaceutical analysis of angiotensin receptor blockers: Olmesartan medoxomil

Hypertension is often asymptomatic and can substantially elevate the risk of cardiovascular complications. Olmesartan medoxomil works by competitively blocking the angiotensin II receptors, preventing angiotensin II from constructing the blood vessels and releasing aldosterone. This discussion is focused on the critical analytical methods used to analyze olmesartan medoxomil in pharmaceutical and biological samples. A variety of analytical methods have been employed to both qualitatively and quantitatively determine the analyte, including high-performance thin-layer chromatography (HPTLC), high-performance liquid chromatography (HPLC), voltammetry, capillary zone electrophoresis, UV/Vis spectrophotometry, and 96-microwell assays. The review also includes official methods published in the Indian Pharmacopoeia. Based on existing literature, simple spectrophotometry and liquid chromatography are commonly used to analyze olmesartan medoxomil. These findings provide a solid foundation for future olmesartan medoxomil drug analysis research.

A multianalyte LC-MS/MS method for accurate quantification of Nitrosamines in Olmesartan tablets

This research summaries the development, optimization and validation of liquid chromatography tandem mass spectrometric (LC-MS/MS) method for concurrent measurement of seven nitrosamines viz; NDMA, NDEA, NDIPA, NDPA, NEIPA, NMPA & NMBA in Olmesartan tablet. Controlling these nitrosamines at trace levels is imperative for ensuring the safety of drug substances and products for consumption. Various regulatory authorities stress the significance of utilizing highly sensitive analytical methods to precisely measure nitrosamines at trace levels. The method applied effective chromatographic separation and optimized parameters for mass spectrometric detection. Detection was carried out using APCI positive ion mode. Chromatographic separation was achieved using a Thermo Accucore PFP column (150 mm x 4.6 mm, 2.6 µ), with a simple gradient elution of mobile phase consisting of 0.1 % formic acid in water (mobile phase A) and methanol (mobile phase B). The total run time was 20 min, with a flow rate of 0.800 mL/min. The method was validated according to the International Council on Harmonisation (ICH Q2 (R2)) guidelines. The established method demonstrated excellent linearity (R2> 0.99) and sensitivity for all the nitrosamines. Detection and quantification limits were sufficiently low for trace nitrosamine levels having good S/N ratio. The method showed good accuracy in Olmesartan tablet samples, with recoveries ranges between 80 % to 120 %. The new analytical approach has exceptional repeatability and reliability, making it possible to precisely quantify the levels of seven nitrosamines in Olmesartan medoxomil tablets in a single analytical run.

Different spectrophotometric and TLC-densitometric methods for determination of olmesartan medoxomil and hydrochlorothiazide and their degradation products

In this work, multivariate calibration models and TLC-densitometric methods have been developed and validated for quantitative determination of olmesartan medoxomil (OLM) and hydrochlorothiazide (HCZ) in presence of their degradation products, olmesartan (OL) and salamide (SAL), respectively. In the first method, multivariate calibration models including principal component regression (PCR) and partial least square (PLS) were applied. The wavelength range 210-343 nm was used and data was auto-scaled and mean centered as pre-processing steps for PCR and PLS models, respectively. These models were tested by application to external validation set with mean percentage recoveries 99.78, 100.01, 100.41 and 100.46% for OLM, HCZ, OL and SAL, respectively, for PLS model and also, 100.22, 100.40, 102.25 and 100.13% for them, respectively, for PCR model. The second method is TLC-densitometry at which the chromatographic separation was carried out using silica gel 60F254 TLC plates and the developing system consisted of a mixture of ethyl acetate:chloroform:methanol: formic acid:tri-ethylamine (60:40:4:4:1, by volume) with UV-scanning at 254 nm. The developed methods were successfully applied for determination of OLM and HCZ in their pharmaceutical dosage form. Also, statistical comparison was made between the developed methods and the reported method using student’s-t test and F-test and results showed that there was no significant difference between them concerning both accuracy and precision.

Olmesartan

Olmesartan is an angiotensin receptor blockers with actions similar to those of losartan; it is used for the treatment of high blood pressure by relaxing blood vessels for this reason blood can flow more easily. It could be used alone or in combination with other antihypertensive drugs. This chapter gives a comprehensive profile of olmesartan, containing detailed nomenclature, formulae, elemental analysis, and appearance of the drug. In addition this chapter also describes several methods of synthesis and usage of the olmesartan. The profile covers the physicochemical properties including pK_a value, solubility, X-ray powder diffraction, melting point, and procedures of analysis (compendial, spectroscopic, electrochemical, and chromatographic techniques of analysis). Comprehensive pharmacology is also presented (pharmacological actions, therapeutic uses and dosing, interactions, and adverse effects and precautions). Eighty references were given as a proof of the above-mentioned studies.

Central Composite Design for Validation of HPTLC Method for Simultaneous Estimation of Olmesartan Medoxomil, Amlodipine Besylate and Hydrochlorothiazide in Tablets

High performance thin layer chromatographic method for simultaneous estimation of olmesartan medoxomil, amlodipine besylate and hydrochlorothiazide was developed and validated as per ICH guidelines. Moreover, robustness testing was performed applying a central composite design with k factor having 2(k) factorial runs, 2k axial experiments and two center points. High performance thin layer chromatographic separation was performed on aluminium plates precoated with silica gel 60F254 and toluene:chloroform:methanol:acetonitrile:formic acid (2:7:1.8:0.8:0.2% v/v) as optimized mobile phase. The detection wavelength for simultaneous estimation of three drugs was 232nm. The Rf values for olmesartan medoxomil, amlodipine besylate and hydrochlorthiazide were 0.78, 0.20 and 0.45, respectively. Percent recoveries in terms of accuracy for the marketed formulation was found to be 101.3-104.4, 100.7-104 and 101.5-103.9 for, olmesartan medoxomil, amlodipine besylate and hydrochlorthiazide, respectively. The pooled %relative standard deviation values for repeatability studies and intermediate precision studies was found to be less than 2% for olmesartan medoxomil, amlodipine besylate and hydrochlorthiazide, respectively. All the three factors evaluated in the robustness testing by central composite design were found to have an insignificant effect on the retention factor. However, methanol content in total mobile phase as a factor appeared to have significant effect on robustness, compared to band size and developing distance and hence it is important to be carefully controlled. In summary, a novel, simple, accurate and reproducible high performance thin layer chromatographic method was developed, which would be of use in quality control of these tablets.

Analysis of Sartans: a review

The risk of cardiovascular diseases is closely related to hypertension, high cholesterol levels, and diabetes. When these risk factors appear together they are referred to as a metabolic syndrome. In the treatment of cardiovascular diseases, a combination of antihypertensive, hypolipemiant, and antidiabetic drugs is often applied. Diuretics (chlortalidone, hydrochlorothiazide, etc.) and angiotensin II receptors antagonist (sartans) are used to control hypertension, whereas statins (fluvastatin, simvastatin, etc.) are used to reduce cholesterol levels. This review is concerned with methods for the analysis of sartans in various matrices, such as pharmaceutical formulations, environmental and biological samples, and discusses the current status of stability studies of sartans . It also presents analytical methods for the simultaneous determination of sartans, diuretics, and statins.

Application of a Stability-Indicating HPTLC Method for Simultaneous Quantitative Determination of Olmesartan Medoxomil and Hydrochlorothiazide in Pharmaceutical Dosage Forms

A rapid, precise, sensitive, economical, and validated high performance thin layer chromatographic method is developed for simultaneous quantification of olmesartan medoxomil and hydrochlorothiazide in combined tablet dosage form. The method used amlodipine as internal standard (IS). Chromatographic separations were achieved on silica gel 60 F254 plates using toluene-methanol-ethyl acetate-acetone (2.5 : 1 : 0.5 : 2, v/v/v/v) as mobile phase. Densitometric analysis was carried out in the reflectance mode at 258 nm. Calibration curves were linear over a range of 80-480 ng/band for olmesartan medoxomil and 25-150 ng/band for hydrochlorothiazide. The detection and quantification limits were found to be 18.12 and 56.35 ng/band for olmesartan medoxomil and 6.31 and 18.56 ng/band for hydrochlorothiazide, respectively. Intra- and interassay precision provided relative standard deviations lower than 2% for both analytes. Recovery from 99.60 to 101.22% for olmesartan medoxomil and 98.30 to 99.32% for hydrochlorothiazide show good accuracy. Both the drugs were also subjected to acid, alkali, oxidation, heat, and photodegradation studies. The degradation products obtained were well resolved from pure drugs with significantly different R f values. As the method could effectively separate the drugs from their degradation products, it can be used for stability-indicating analysis. Validation of the method was carried out as per international conference on harmonization (ICH) guidelines.

Simultaneous Quantitative Determination of Nine Active Chemical Compositions in Traditional Chinese Medicine Glycyrrhiza by RP-HPLC with Full-Time Five-Wavelength Fusion Method

A new, simple, accurate and reliable full-time five-wavelength fusion method for the simultaneous separation and determination of nine active chemical compositions (liquiritin apioside, liquiritin, isoliquiritin apioside, ononin, isoliquiritin, liquiritigenin, calycosin, isoliquiritigenin, Glycyrrhizic acid monoammonium salt) in traditional Chinese medicine Glycyrrhiza was developed using reverse phase high-performance liquid chromatography (RP-HPLC) coupled with a diode-array detector (DAD). The chromatographic separation was performed on an Agilent TC-C18 column with gradient elution using 0.04% methanoic acid (A) and acetonitrile (B) at a flow rate of 1.0 mL min-1 and UV detection at 248 nm, 250 nm, 276 nm, 362 nm, 370 nm. The standard curves were linear over the range of 2.1379–12.8272 μg for liquiritin apioside, 3.9299–23.5794 μg for liquiritin, 1.0432–6.2592 μg for isoliquiritin apioside, 0.8764–5.8584 μg for ononin, 1.0701–6.4205 μg for isoliquiritin, 1.3685–8.2111 μg for liquiritigenin, 0.3927–2.3563 μg for calycosin, 0.2498– 1.4986 μg for isoliquiritigenin, 2.0094–12.0564 μg for Glycyrrhizic acid monoammonium salt, respectively (r2 > 0.9997). The recoveries and relative standard deviation (RSD) varied from 95.09% to 103.54% and 1.09% to 2.36%, respectively. The precision for all the analytes was less than 2.52%. The method indicated good performance in terms of precision, accuracy and linearity. The method enabled the simultaneous determination of nine active chemical compositions for quality control of Glycyrrhiza.

Electrochemical determination of olmesartan medoxomil using hydrothermally prepared nanoparticles composed SnO2-Co3O4 nanocubes in tablet dosage forms

Low-dimensional nanoparticles composed SnO(2)-Co(3)O(4) nanocubes (NCs) were prepared by a hydrothermal method using reducing agents. The doped nanomaterials were investigated by UV/vis, powder X-ray diffraction, FT-IR, energy-dispersive X-ray spectroscopy (EDS), and Raman spectroscopy, and field-emission scanning electron microscopy. They were deposited on a silver electrode (AgE, surface area, 0.0216 cm(2)) to give a drug sensor with a fast response towards Olmesartan medoxomil (OSM) in 0.1 mol L(-1) phosphate buffer-phases. The sensor also exhibits higher sensitivity, long-term stability, and enhanced electrochemical response. The calibration plot is linear (r(2)=0.9948) over the 0.28 nmol L(-1)-1.4 μM OSM concentration range. The sensitivity is ~2.083 μA cm(-2) mmol L(-1) and the detection limit is 0.17 nmol L(-1) (at an SNR of 3). We discuss the possible potential uses of this nanoparticles doped semiconductor NCs in terms of drug sensing, which could also be employed for the determination of drugs in quality control of formulation.

Development of a novel 96-microwell assay with high throughput for determination of olmesartan medoxomil in its tablets

A novel 96-microwell-based spectrophotometric assay has been developed and validated for determination of olmesartan medoxomil (OLM) in tablets. The formation of a colored charge-transfer (CT) complex between OLM as a n-electron donor and 2, 5-dichloro-3, 6-dihydroxy-1, 4-benzoquinone (p-chloranilic acid, pCA) as a π-electron acceptor was investigated, for the first time, and employed as a basis in the development of the proposed assay. The proposed assay was carried out in 96-microwell plates. The absorbance of the colored-CT complex was measured at 490 nm by microwell-plate absorbance reader. The optimum conditions of the reaction and the analytical procedures of the assay were established. Under the optimum conditions, linear relationship with good correlation coefficient was found between the absorbance and the concentration of OLM in the range of 1-200 μg ml-1. The limits of detection and quantitation were 0.3 and 1 μg ml-1, respectively. No interference was observed from the additives that are present in the pharmaceutical formulation or from hydrochlorothiazide and amlodipine that are co-formulated with OLM in some formulations. The assay was successfully applied to the analysis of OLM in tablets with good accuracy and precision. The assay described herein has great practical value in the routine analysis of OLM in quality control laboratories, as it has high throughput property, consumes minimum volume of organic solvent thus it offers the reduction in the exposures of the analysts to the toxic effects of organic solvents, and reduction in the analysis cost by 50-fold. Although the proposed assay was validated for OLM, however, the same methodology could be used for any electron-donating analyte for which a CT reaction can be performed.