Simultaneous Quantitative Analysis of Olmesartan Medoxomil and Amlodipine Besylate in Plasma by High-performance Liquid Chromatography Technique

Four chemometric spectrophotometric methods for simultaneous estimation of amlodipine besylate and olmesartan medoxomil in their combined dosage form

For determination of amlodipine besylate (AML) and olmesartan medoxomil (OLM) at the same time, four UV chemometric spectrophotometric techniques were created and tested in accordance with ICH standards. Method (I) was absorption subtraction method (ASM) using two wavelengths, one of which was of AML at 365 nm and the other was the isoabsorptive point of both drugs at 237 nm. Method (II) was ratio subtraction method (RSM) for determination of OLM at λ_max = 254 nm by taking the ratio spectrum and subtracting the constant values using 10 μg/mL of AML as a divisor in combination with extended ratio subtraction method (ERSM) to determine AML at λ_max = 239 nm using 10 μg/mL OLM as a divisor. Method (III) was dual wavelength method; the wavelengths used to determine OLM were 221 nm and 235 nm, while those used to determine AML were 246 nm and 259 nm. Method (IV) was the second order derivative (²D) spectrophotometric method at 219 nm for OLM and 227 nm for AML. The proposed approaches were used to achieve linearity in the concentration range of 2-25 μg/mL for both drugs. The approaches were found to be uncomplicated, reproducible, efficient, and cost-effective as well as they were successfully used to determine the cited drugs in both laboratory samples and commercial pharmaceutical formulations.

Electrochemical sensing of dobutamine, paracetamol, amlodipine, and daclatasvir in serum based on thiourea SAMs over nano-gold particles-CNTs composite

We report in this work a one-step approach for the formation of self-assembled monolayers (SAMs) from thiourea (TU) over gold nanoparticles dispersed in carbon nanotubes (CNTs-Aunano). The fabrication of the...

Design and optimization of nano invasomal gel of Glibenclamide and Atenolol combination: in vitro and in vivo evaluation

Background

There are many circumstances where chronic disease is associated with other disorders, especially in diseases such as diabetes with noncommunicable disease risk factors, such as hypertension. The current therapies for treating such chronic comorbid diseases are limited and challenging due to the difficulties in overcoming the side effects from complex therapeutic treatment regimen. The present study is aimed to develop and optimize the combinational nano invasomal gel of Glibenclamide (GLB) and Atenolol (ATN) as a novel combination therapy for comorbid treatment of diabetic hypertensive patients. The developed formulations were characterized for various parameters, including in-vitro skin permeation, skin irritation, in-vivo antidiabetic, and antihypertensive activities.

Results

OCNIG showed that the % entrapment efficiency of GLB is 96.67 ± 0.65% and % entrapment efficiency of ATN is 93.76 ± 0.89%, flux of GLB (240.43 ± 1.76 μg/cm2/h), and flux of ATN (475.2 ± 1.54 μg/cm2/h) which was found to conform to the expected value. The results indicated desired release and permeation profiles. Optimized formulation showed significant pharmacokinetic properties, which shows improvement in bioavailability by 134.30% and 180.32% respectively for two drugs, when compared to marketed oral preparation. Pharmacodynamic studies showed improved and prolonged management of diabetes and hypertension in Wistar rats, compared to oral and drug-loaded nano invasomes formulations.

Conclusion

Overall, the results showed that nano invasomal gel was found to be a useful and promising transdermal delivery system for the treatment of concurrent diseases.

Trade-off efficacy and data processing strategy in the power of spectral resolution of co-formulated antihypertensive pharmaceuticals

Versatile, extraction-free univariate spectrophotometric methods have been modified to get effective spectral resolution of mixtures in accordance with their feature challenges. The proposed methods have been applied and validated for analyzing some antihypertensive medicines in their co-formulated medicinal products. Two mixtures have been used: the first one [Mix I _(OLM/ADB)] is composed of Olmesartan medoxomil (OLM) and Amlodipine besylate (ADB) with partly-overlapped spectra while the second [Mix II _(TEL/HCT)] is made up Telmisartan (TEL) and Hydrochlorothiazide (HCT) with total-overlapped spectra. Induced dual wavelength, absorbance correction and ratio subtraction coupled with constant multiplication methods were applied to Mix I _(OLM/ADB), while dual wavelength, advanced absorbance subtraction and constant center coupled with spectrum subtraction methods were applied to Mix II _(TEL/HCT). Calibration graphs were established with good correlation coefficients. The methods exhibit significant advantages as simplicity, sensitivity, minimal data manipulation besides optimum robustness. Selectivity was inspected using lab-mixtures with diverse ratios. Accuracy, precision and repeatability were found to be within the acceptable limits. The proposed methods are good enough to be used for co-assay of analytes in combined forms without any interfering from excipients. Moreover, all results were estimated in accordance with ICH criteria and successfully compared with those of the reported methods applying t-test and F-test at 95% confidence level. Generally, these methods can be used efficiently for routine quality control testing.

Analytical and Bioanalytical Techniques for the Quantification of the Calcium Channel Blocker - Amlodipine: A Critical Review

Hypertension is a condition in which blood pressure is elevated to an extent where benefit is obtained from blood pressure lowering. The risk of complications is proportional to the level that blood pressure raises. Calcium channel blockers are a class of compounds used in the treatment of hypertension. The dihydropyridine (DHP) group, a subclass of the calcium channel blocker works almost exclusively on L-type calcium channels in the peripheral arterioles and reduce blood pressure by reducing total peripheral resistant. Long acting DHP is preferred because they are more convenient for patients and avoid the large fluctuations in plasma drug concentration which are associated with side effects. Amlodipine is the most distinct DHP and the most popular. The drug was patented in the year 1986 and its commercial sale began by 1990. The current article provides a state of art about the analytical and bioanalytical techniques available for the quantification of drug as a single entity and in combined pharmaceutical formulations between 1989 and 2019.

Development and validation of simple simultaneous analysis for amlodipine and glibenclamide by nonderivatization high-performance liquid chromatography-fluorescence

Studies have shown that about 65% of diabetics have hypertension. Treatment for diabetic patients with hypertension is usually given a combination of drugs such as amlodipine (AML) and glibenclamide (GLI). The aim of this study was to develop and validate the simple simultaneous analysis method for separation of AML and GLI using high-performance liquid chromatography (HPLC) with fluorescence detector without derivatization. The arrangement of isocratic and gradient methods, mobile phase compositions, and flow rates to develop and validate the simple simultaneous analysis method for separation of AML and GLI by nonderivatization HPLC fluorescence was done. Optimum condition was obtained using an RP 18 (125 mm × 4 mm, i.d., 5 μm) and guard column RP 18 (4 mm × 4 mm, i.d., 5 μm) with mobile phase composition containing acetonitrile and phosphate buffer pH 3.0 using a 20:80 gradient condition at flow rate 1.0 ml/min measured at 361 nm for λ excitation and 442 nm for λ emission for AML and 235 nm for λ excitation and 354 nm for λ emission for GLI. The analysis of AML and GLI demonstrated a valid result with r ² value 0.999, recoveries were 100.04% and 99.14% relative standard deviations were 0.508% and 0,797%, respectively, detection limits were 0.055 and 0.104 μg/ml, and quantification limits were 0.166 and 0.316 μg/ml, respectively. An accurate method of separation for AML and GLI using HPLC with fluorescence detector without derivatization has been validated.

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.

Development of olmesartan medoxomil optimized nanosuspension using the Box-Behnken design to improve oral bioavailability

The aim of the present investigation was to enhance the oral bioavailability of olmesartan medoxomil by improving its solubility and dissolution rate by preparing nanosuspension (OM-NS), using the Box-Behnken design. In this, four factors were evaluated at three levels. Independent variables include: concentration of drug (X₁), concentration of surfactant (X₂), concentration of polymer (X₃) and number of homogenization cycles (X₄). Based on preliminary studies, the size (Y₁), zeta potential (ZP) (Y₂) and % drug release at 5 min (Y₃) were chosen as dependent responses. OM-NS was prepared by high pressure homogenization method. The size, PDI, ZP, assay, in vitro release and morphology of OM-NS were characterized. Further, the pharmacokinetic (PK) behavior of OM-NS was evaluated in male wistar rats. Statistically optimized OM-NS formulation exhibited mean particle size of 492 nm, ZP of -27.9 mV and 99.29% release in 5 min. OM-NS showed more than four times increase in its solubility than pure OM. DSC and XRD analyses indicated that the drug incorporated into OM-NS was in amorphous form. The morphology of OM-NS was found to be nearly spherical with high dispersity by scanning electron microscopic studies. The PK results showed that OM lyophilized nanosuspension (NS) exhibited improved PK properties compared to coarse powder suspension and marketed tablet powder suspension (TS). Oral bioavailability of lyophilized NS was increased by 2.45 and 2.25 folds when compared to marketed TS and coarse powder suspension, respectively. Results of this study lead to conclusion that NS approach was effective in preparing OM formulations with enhanced dissolution and improved oral bioavailability.

Development of olmesartan medoxomil lipid-based nanoparticles and nanosuspension: preparation, characterization and comparative pharmacokinetic evaluation

The aim was to enhance the oral bioavailability of olmesartan medoxomil (OM) by preparing solid lipid nanoparticles (SLNs) and comparing with nanosuspension (OM-NS). OM-SLNs and OM-NS were prepared by known methods. Prepared SLNs were evaluated for physical characters and in vivo pharmacokinetic (PK) performance in rats. OM-NS showed more than four-fold increase in the solubility. During DSC and XRD studies, drug incorporated in SLNs was found to be in amorphous form. The relative bioavailability of OM-SLN and OM-NS was 7.21- and 3.52-fold when compared with that of coarse suspension. Further, OM-SLNs also increased the oral bioavailability by two-fold over that of OM-NS.

Development and Validation of a Chromatography Method Using Tandem UV/Charged Aerosol Detector for Simultaneous Determination of Amlodipine Besylate and Olmesartan Medoxomil: Application to Drug-Excipient Compatibility Study

A study was carried out to investigate compatibility of amlodipine besylate and olmesartan medoxomil with a variety of pharmaceutical excipients. Both drugs are antihypertensive agents that can be administered alone, in monotherapy, or in pharmaceutical association. The studies were performed using binary and ternary mixtures, and samples were stored for 3 and 6 months at 40°C under 75% relative humidity and dry conditions. For this study, a method based on high-performance liquid chromatography (HPLC) was developed and validated for the simultaneous determination of amlodipine besylate and olmesartan medoxomil in samples from pharmaceutical preformulation studies using diode array detector (DAD) and charged aerosol detector (CAD). The runtime per sample was 10 min with retention time of 7.926 min and 4.408 min for amlodipine and olmesartan, respectively. The validation was performed according to ICH guidelines. The calibration curve presents linear dynamic range from 12 to 250 μg mL^-1 for amlodipine and from 25 to 500 μg mL^-1 for olmesartan with coefficient of determination (R² ≥ 0.9908) while repeatability and reproducibility (expressed as relative standard deviation) were lower than 1.0%. The excipients such as corn starch, croscarmellose sodium, magnesium stearate, polyvinyl alcohol, talc, polyvinylpyrrolidone, lactose monohydrate, and polyethylene glycol showed potential incompatibilities after accelerated stability testing.

Design, formulation and optimization of novel soft nano-carriers for transdermal olmesartan medoxomil delivery: In vitro characterization and in vivo pharmacokinetic assessment

Olmesartan is a hydrophobic antihypertensive drug with a short biological half-life, and low bioavailability, presents a challenge with respect to its oral administration. The objective of the work was to formulate, optimize and evaluate the transdermal potential of novel vesicular nano-invasomes, containing above anti-hypertensive agent. To achieve the above purpose, soft carriers (viz. nano-invasomes) of olmesartan with β-citronellene as potential permeation enhancer were developed and optimized using Box-Behnken design. The physicochemical characteristics e.g., vesicle size, shape, entrapment efficiency and skin permeability of the nano-invasomes formulations were evaluated. The optimized formulation was further evaluated for in vitro drug release, confocal microscopy and in vivo pharmacokinetic study. The optimum nano-invasomes formulation showed vesicles size of 83.35±3.25nm, entrapment efficiency of 65.21±2.25% and transdermal flux of 32.78±0.703 (μg/cm(2)/h) which were found in agreement with the predicted value generated by Box-Behnken design. Confocal laser microscopy of rat skin showed that optimized formulation was eventually distributed and permeated deep into the skin. The pharmacokinetic study presented that transdermal nano-invasomes formulation showed 1.15 times improvement in bioavailability of olmesartan with respect to the control formulation in Wistar rats. It was concluded that the response surfaces estimated by Design Expert(®) illustrated obvious relationship between formulation factors and response variables and nano-invasomes were found to be a proficient carrier system for transdermal delivery of olmesartan.

Simultaneous estimation of amlodipine and atenolol in human plasma: a sensitive LC–MS/MS method validation and its application to a clinical PK study

Background: A highly sensitive, specific and rapid LC–ESI-MS/MS method has been developed and validated for simultaneous quantification of amlodipine (AMD) and atenolol (ATL) in human plasma (200 µl) using AMD-d4 and ATL-d7, respectively, as an internal standard (IS) as per the regulatory guidelines. Results: The SPE method was used to extract the analytes and IS from human plasma. The chromatographic resolution of AMD, ATL and corresponding IS was achieved using an isocratic flow on a C18 column. The total chromatographic run time was 3 min. A linear response function was established for the range of concentrations 50–8000 pg/ml and 10–800 ng/ml for AMD and ATL, respectively, in human plasma. Conclusion: The intra- and inter-day accuracy and precision values for AMD and ATL met the acceptance as per regulatory guidelines. The validated assay was applied to a fixed-dose combination of AMD and ATL (Adopin-AT®) PK study in humans.