Green HPTLC-densitometric approach for simultaneous determination and impurity- profiling of ebastine and phenylephrine hydrochloride

Novel HPTLC method for simultaneous estimation from ternary mixture of chlorpheniramine maleate, dextromethorphan hydrobromide and phenylephrine hydrochloride in syrup formulations

OBJECTIVES

A synergic antihistamine, cough suppressant, and decongestant combination of chlorpheniramine, dextromethorphan, and phenylephrine is used to treat acute respiratory infections caused by seasonal viruses. The effective qualitative and quantitative methods require the simultaneous measurement of a ternary combination in the pharmaceutical syrup dosage form. Therefore, a new, simple, fast and robust high performance thin layer chromatographic (HPTLC) method has been developed and validated for chlorpheniramine maleate (CPM), dextromethorphan hydrobromide (DEXO) and phenylephrine hydrochloride (PE).

MATERIAL AND METHODS

The chromatographic separation was carried out on precoated aluminium plates with silica gel 60 F254 as the stationary phase. Mobile phase used was chloroform: methanol: ammonia (2.5:7.5:0.3, v/v/v) for proper separation. The detection was carried out at 270nm wavelength in absorbance mode. Developed method was validated as per International Council for Harmonization (ICH) Q2 (R1) guideline.

RESULTS

The linearity range is 400 to 1400ng/band for CPM, 3000 to 11500ng/band for DEXO and 1000 to 3500ng/band for PE with correlation coefficient ≥ 0.995. The consistent lower values of relative standard deviation (RSD, %) for precision and robustness study indicate the method reliability. The percent recovery ranged from 97.82 to 102.03% indicates the good accuracy of the method.

CONCLUSION

The proposed method was complying for the analytical method validation parameters suggested by the ICH Q2 (R1) guideline. The method was found to be simple, rapid and reliable for the simultaneous estimation of CPM, DEXO and PE from its pharmaceutical syrup dosage form. The method was successfully applied to quantify these analytes from the several pharmaceutical syrup dosage form.

Stability and Biosimilarity Assessment of Bevacizumab Monoclonal Antibody; Orthogonal Testing Protocol Coupled With Peptide Mapping-Principal Component Analysis

BACKGROUND

Biologics are essential in cancer treatment because they stimulate the body's natural response to fight cancer, but they are expensive. Biosimilars are more affordable compared to patent biologicals, but it must be verified that they are as effective as their innovators. Characterization of biosimilars and assessment of interchangeability requires many data points for verification.

OBJECTIVE

The proposed study provides a quality assessment of two new bevacizumab (BVZ) biosimilars, produced by Amgen and Biocad, Inc., through the development and greenness assessment of an orthogonal testing protocol and purity indicating assay, including size-exclusion (SE-HPLC), reversed-phase (RP-HPLC), and cation exchange chromatography (CEX-HPLC) in addition to dynamic light scattering (DLS) and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE).

METHODS

SE-HPLC method was performed and validated to screen the BVZ monomer and its aggregates and/or fragments. Peak purity and system suitability parameters were calculated. Results indicate that the orthogonal protocol is a useful tool for assessing monoclonal antibody stability. It is a key criterion for biosimilarity assessment. DLS and SDS-PAGE results were compared to each other to reveal close retention times and banding patterns between BVZ innovator and its biosimilars. These results showed that Avastin® and the investigated biosimilars have the same profile in terms of peak area of related compounds within the acceptance limit and apparent molecular weight, and the SDS-PAGE technique was found to be the most eco-friendly technique among others.

CONCLUSIONS

The results obtained highlighted the importance of assessing similarities and differences in ensuring the biosimilarity and interchangeability of the studied products.

HIGHLIGHTS

BVZ is one of the essential monoclonal antibodies in the treatment of colorectal cancer (CRC). BVZ biosimilars were evaluated by developing an orthogonal testing protocol and a purity-indicating assay. The size-exclusion (SE)-HPLC method was applied and validated to monitor the BVZ monomer and its aggregates. The results demonstrated the importance of assessing the stability and biosimilarity of BVZ.

Expeditive Chromatographic Methods for Quantification of Solifenacin Succinate along with its Official Impurity as the Possible Acid Degradation Product

Two selective stability-indicating procedures were adopted for the quantification of Solifenacin succinate (SOL) along with its acid degradant, in its powder form or in pharmaceutical tablet. Under stress conditions, the acid degradation pathway of SOL was investigated, its official impurity (SOL imp-A) was obtained as the possible acid degradation product, also. A densitometric technique based on the separation of SOL from SOL imp-A employing HPTLC plates prelaminated with silica gel 60 F254 as the stationary phase and a developing solution containing methanol:chloroform:ammonia (8:1:1, v/v/v) and UV scanning of the developed bands at 220 nm. Linear regression analysis data for the calibration plot of SOL showed perfect linear relationships throughout the range of concentration 10-60 μg/band. A reversed phase C18 analytical column (4.6 × 250 mm, 5 μm) was also used to separate the mixture at a flow rate of 1 mL/min, using acetonitrile:0.05 M phosphate buffer (70:30, v/v) as the mobile phase and phosphoric acid to set pH = 3.5. Quantification was obtained at 220 nm using peak area and linear calibration curve across a concentration range of 10-70 μg/mL. The recommended procedures were applied to the existing dosage form, and they generated satisfactory results.

Chitosan nanoparticles modified TLC-densitometry for determination of imidacloprid and deltamethrin residues in plants: greenness assessment

Two thin layer chromatography (TLC) methods have been developed for the determination of pesticides residues of imidacloprid (IMD) and deltamethrin (DLM) in thyme and guava leaves. In the two methods, the used stationary phase was silica gel 60 F₂₅₄ plates impregnated in chitosan nanoparticles (ChTNPs) 0.5% to improve separation using a green developing system consists of isopropyl alcohol for IMD and n-hexane-toluene-ethylacetate for DLM. The two pesticides were determined quantitatively, after TLC separation, at wavelengths 270.0 nm for IMD and 230.0 nm for DLM. Validation of both approaches was carried out in agreement with the guidelines of International Conference on Harmonization (ICH) and found to be selective, reliable and reproducible. Limits of detection of IMD and DLM were 0.002 and 0.00116 μg/spot, respectively. The newly developed TLC methods were used to monitor the pre-harvest interval estimation. Analytical eco-scaling depending on penalty points for IMD was calculated and showed that this method was eco-friendlier than the reported one.

Quality Control of the Dietary Supplements Containing Selected Fat-Soluble Vitamins D and K

Nowadays, the most important aspect related to the use of dietary supplements seems to be their quality. There are many reports indicating their insufficient quality primarily related to a much lower content of ingredients or even their absence. Currently, there is an increasing interest in supplementing the diet with various kinds of supplements, including those containing combinations of vitamins and minerals, among which preparations with vitamin D are very popular. This is probably due to the reduced production of this vitamin, depending on the amount of time spent in the sun and the use of UV-filters. Very often, preparations with cholecalciferol also contain vitamin K2, which is associated with their synergistic effect. Therefore, the question arises about the effectiveness of supplementation, which may be correlated with the quality of commonly available dietary supplements. In the presented work, it was undertaken to develop optimal conditions for the qualitative and quantitative determination of vitamins D2, D3 and K2 in dietary supplements available in various forms, using thin-layer chromatography with densitometric detection. As a result, the methodology for analyzing the content of three vitamins from various matrices was developed, optimized and validated in accordance with ICH requirements. The obtained results allow us to conclude that it is reliable and meets the requirements for analytical procedures used in the analysis of medicinal products. Based on the results obtained for examined dietary supplements, it can be stated that the amount of vitamin D3 in analyzed products is basically similar to that declared by the manufacturer, in contrast to vitamin K2, the content of which is diverse. The developed methodology seems to be a good, low-cost and quick way to control the quality of dietary supplements so that they can supplement the human diet and be a wholesome product.

Application of Chemometry and Design of Experiments to Green HPTLC Method for Synchronous Estimation of Multiple FDCs of Cilnidipine

BACKGROUND

Numerous fixed-dose combinations (FDCs) of cilnidipine (CIL) with chlorthalidone (CLT) and azilsartan medoxomil (AZL) are used for the treatment of hypertension. Numerous reverse-phase high-pressure liquid chromatography (RP-HPLC) and high-performance thin-layer chromatography (HPTLC) methods have been reported in the literature for the estimation of FDCs of CIL. But no HPTLC method has been reported yet for synchronous estimation of multiple FDCs of CIL to save time, organic solvent, and cost of analysis. In the recent scenario of green chemistry, the minimum usage of organic solvent in the development of the chromatographic method is highly desirable for the safety of the environment and analysts.

OBJECTIVE

Hence, a robust and green HPTLC method has been developed for the synchronous estimation of multiple FDCs of CIL using the analytical quality by design (AQbD) approach.

METHODS

The chemometric tool was applied for the identification of the critical method variables (CMVs) and critical analytical attributes (CAAs) for the HPTLC method development. The design of experiments (DoE) was applied for the response surface analysis of identified CMVs and CAAs using the Box-Behnken design. The analytical design space and control strategy was framed for the lifecycle management of the HPTLC method.

RESULTS

The chromatographic separation was performed using silica gel G60 F254 as the stationary phase and toluene-ethyl acetate-methanol (6.5 + 2 + 1.5, v/v) as the mobile phase. The method was validated as per the International Council for Harmonization Q2 (R1) guideline. The developed method was applied for the synchronous estimation of multiple FDCs of CIL, and results were found in compliance with labeled claims.

CONCLUSIONS

The developed HPTLC method can be used as a green, economical, and rapid analytical tool for routine analysis and quality control of multiple FDCs of CIL in the pharmaceutical industry.

HIGHLIGHTS

Development of a HPTLC method for synchronous estimation of multiple FDCs of CIL using the AQbD approach based on principles of chemometry and DoE. Application of the developed method for synchronous assay of multiple FDCs of CIL to save time, cost, and solvent for analysis.

Analytical Eco-Scale for Evaluating the Uniqueness of Voltammetric Method used for Determination of Antiemetic Binary Mixture Containing Doxylamine Succinate in Presence of its Toxic Metabolite

Green analytical procedures are gaining popularity in the pharmaceutical research area as a way to reduce environmental impact and improve analyst health safety. The current work presents a green and sensitive electrochemical carbon paste electrode that has been chemically modified with zirconium dioxide and multi-walled carbon nanotubes for estimation of pyridoxine HCl (PYR) and doxylamine succinate (DOX) using the square wave voltammetric technique. Under optimum conditions, the linearity ranges were 20.00–2000.00 ng mL−1 and 2.00–20.00 µg mL−1 for both drugs in the 1st linear segment and 2nd linear segment, respectively. Stability testing assesses how the quality of a drug substance changes over time, depending on environmental and laboratory factors. DOX was found to undergo oxidative degradation when refluxed for 7 h using 30% H2O2 and the degraded product (DOX DEG) (toxic metabolite) was successfully characterized utilizing LC–MS. The developed electrode showed selectivity for the determination of binary mixture in pure form, pharmaceutical form, and in the presence of DOX DEG and common interfering molecules with good recovery. The proposed method was found to be eco-friendlier than the reported method in terms of the use of hazardous chemicals and solvents, energy consumption, and waste generation.

Graphical Abstract

Green Analytical Approach for the Determination of Zinc in Pharmaceutical Product Using Natural Reagent

A selective, sensitive, and environmentally safe spectrophotometry method was developed and validated for the determination of zinc in pharmaceutical substances using natural reagents obtained from the leaves of plant Acacia catechu. Different factors were optimized such as volume of reagent, selection of pH, and stability of the color complex. The drug showed a stable yellowish orange color complex at 550 nm. The greenness of the methods was estimated using an eco-scale tool where the presented method was found to be excellent green with an ecoscore of 84 based on spectrophotometric determination. Also, the greenness of the method was assessed by the Green Analytical Procedure Index and found to be eco-friendly. The method was validated in conformance with ICH guidelines, with acceptable values for linearity, accuracy, precision, LOD, and LOQ. The linearity range for zinc sulphate was 5–25 μg mL−1 with an R2 value of 0.996. The % RSD for intraday precision and interday precision was less than 2%. The suggested method can be employed for the economic analysis of zinc in its pure form and various formulations. The presented spectrophotometric method is the first analytical method for the analysis of zinc present in zinc sulphate and showed greater ecoscale as compared to the official method.

Sustainable Liquid Chromatographic Determination and Purity Assessment of a Possible Add-on Triple-Action Over-the-counter Pharmaceutical Combination in COVID-19

Nowadays, all researchers are focused on combating the pandemic COVID-19. According to recent statistics, most patients are managed at home. An over-the-counter (OTC) triple action formula containing paracetamol (PAR), aspirin (ASP), and diphenhydramine (DIPH) is widely prescribed for pain, fever and as night-time sleep aid. For COVID-19 patients, this combination is now suggested as part of symptomatic therapy and prophylaxis. In this work, two simple liquid chromatographic approaches were designed for simultaneous determination of PAR, ASP, and DIPH in Excedrin® PM caplets, beside three specified official toxic impurities, namely, p-aminophenol, p-nitrophenol, and salicylic acid. The first method comprised high-performance thin-layer chromatographic separation coupled with densitometric quantification, on silica gel HPTLC 60 F₂₅₄ aluminium sheets as the stationary phase, ethyl acetate–methanol-aqueous ammonium hydroxide (10.0: 2.0: 0.1, by volume) as the developing system and scanning was performed at 210.0 nm. The second one is a high-performance liquid chromatography coupled with diode array detector. Successful separation of the six components was performed on XTerra C₁₈ column with isocratic elution of mobile phase 0.1% triethylamine acidified water: methanol (70:30, v/v) adjusted with o-phosphoric acid to pH 3.0 and methanol (90:10, v/v) with flow rate programming and detection at 210.0 nm. Validation of the proposed methods was performed according to ICH guidelines. Both methods were successfully used for quality control of the cited drugs in their marketed formulation. Moreover, the in-vitro release study was monitored using the proposed HPLC-DAD method. The greenness profile of the proposed methods was assessed and comparatively evaluated through various assessment tools, specifically; the analytical eco-scale system, national environmental method index (NEMI), green analytical procedure index (GAPI) and analytical greenness (AGREE) metric.

An Overview of Advances in the Chromatography of Drugs Impurity Profiling

A systematic literature survey published in several journals of pharmaceutical chemistry and of chromatography used to analyze impurities for most of the drugs that have been reviewed. This article covers the period from 2016 to 2020, in which almost of chromatographic techniques have been used for drug impurity analysis. These chromatography techniques are important in the analysis and description of drug impurities. Moreover, some recent developments in forced impurity profiling have been discussed, such as buffer solutions, mobile phase, columns, elution modes, and detectors are highlighted in drugs used for the study. This primarily focuses on thorough updating of different analytical methods which include hyphenated techniques for detecting and quantifying impurity and degradation levels in various pharmaceutical matrices.

Recent Progresses in Analytical Perspectives of Degradation Studies and Impurity Profiling in Pharmaceutical Developments: An Updated Review

Forced degradation studies have been used to simplify analytical methodology development and achieve a deeper knowledge about the inherent stability of active pharmaceutical ingredients (API) and drug products. This provides insight into degradation species and pathways. Identification of impurities in pharmaceutical products is closely related to the selection of the most appropriate analytical methods like HPLC-UV, LC-MS/MS, LC-NMR, GC-MS, and capillary electrophoresis. Herein, recent trends in analytical perspectives during 2018-April 14, 2021, are discussed based on forced and impurity degradation profiling of pharmaceuticals. Literature review showed that several methods have been used for experimental design and analysis conditions such as matrix type, column type, mobile phase, elution modes, detection wavelengths, and therapeutic category. Thus, since these factors influence the separation and identification of the impurities and degradation products, we attempted to perform a statistical analysis for the developed methods according to the abovementioned factors.

Two green chromatographic methods for the quantification of tamsulosin and solifenacin along with four of their impurities

Modern analytical procedures often include impurity profiling to verify the potency, safety, and effectiveness of new formulations. We had to develop techniques based on green analysis since the detrimental influence of solvents and chemicals on the environment has now become a serious concern. Two selective, sensitive and green LC methods were established and fully validated for quantitation of tamsulosin hydrochloride and solifenacin succinate along with four of their official and/or related impurities namely; tamsulosin sulfonic acid, tamsulosin impurity H, solifenacin impurity A and solifenacin impurity C. The first used High Performance Thin Layer Chromatography with silica gel 60 F254 plates as the stationary phase and an elution system of ethyl acetate:butanol:glacial acetic acid (10.0:0.4:0.1, by volume) and a scanning wavelength of 225.0 nm. The second method depended on HPLC with diode array detection. Chromatographic separation was accomplished on a Zorbax^® SB C₁₈ (250 × 4.6 mm² , 5 μm) column utilizing a mixture of 10.0 mM sodium dihydrogen phosphate (pH 3.0, adjusted by o-phosphoric acid) and methanol, at a flow rate of 0.8 mL/min in a gradient elution mode and then the separated peaks were scanned at a wavelength of 225.0 nm. To assess the greenness profile, three distinct methodologies were applied. This article is protected by copyright. All rights reserved.

Versatile TLC-Densitometric Methods for the Synchronous Estimation of Cinnarizine and Acefylline Heptaminol in The Presence of Potential Impurity and Their Reported Degradation Products

From evolution, thin-layer chromatography (TLC) attracts attention as a versatile technique for efficient separation and identification of many drug substances and chemicals. Owing to its simplicity and other outstanding advantages, TLC is extensively used by chromatographers in quantification and purity profiling objectives. In the present study two TLC-Densitometric methods are established and validated for the synchronous estimation of Cinnarizine (Cinn) and Acefyline Heptaminol (Acef) in the presence of Cinn/Acef reported degradation products and Thoephylline (Theo) as Acef potential impurity. The proposed methods are based on densitometric measurements of the spots of Cinn and Acef after separation from their degradation products. Separation is attained on silica gel sheet with dichloromethane: methanol: formic acid as a developing system in ratio: (15, 1, 0.5, by volume) and (15, 0.75, 0.4, by volume) for Cinn (method 1) and Acef (method 2) degradation, consecutively. Quantification is done at 254 nm over concentration ranges of 0.2-1.8 and 2-18 μg/spot for Cinn and Acef; respectively, with mean percentage recoveries of 99.18 ± 0.60/99.84 ± 0.53 and 99.19 ± 0.93/99.66 ± 0.58 for method 1 and method 2; consecutively. The two methods are fully validated and proven to be selective, robust and retained their accuracy in up to 50% of Cinn/Acef reported degradation products and Theo. Moreover, the two methods are applied to a coformulated drug product comprising Cinn and Acef showing satisfactory results. Comparison of the obtained results by the proposed methods with that of the reference ones statistically shows no significant differences.

Identification of type B trichothecenes and zearalenone in Chilean cereals by planar chromatography coupled to mass spectroscopy

High-performance thin-layer chromatography (HPTLC) and HPTLC coupled with mass spectrometry (MS) methods were described for the simultaneous determination of zearalenone (ZEA); type B trichothecenes (TCT-B); nivalenol (NIV) and deoxynivalenol (DON) along with its acetylated derivatives: 3-acetyldeoxynivalenol (3-ADON) and 15-acetyldeoxynivalenol (15-ADON). The extract samples were cleaned-up with Bond Elut Mycotoxin^® solid-phase extraction cartridges. Then, separation was performed on HPTLC silica gel 60 F₂₅₄ plates using toluene, ethyl acetate and formic acid (1:8:1 v/v/v) as mobile phase. Derivatisation was then performed with 10% aluminium trichloride in 50% methanol. Mycotoxin standards and spiked cereals grains were identified by UV spots at 366 nm, with retention factors (R_F) of 0.20 (NIV), 0.39 (DON), 0.45 (15-ADON), 0.50 (3-ADON) and 0.60 (ZEA). Some parameters of validation were determined. Calibration data (n = 5) fitted a linear regression model with determination coefficients, R² > 0.99. The recovery was determined in triplicate at two levels, ranging from 84.3 ± 2.2% to 114.2 ± 11.7%. Detection limits ranged from 80 to 120 μg kg^-1 and quantification limits ranged from 120.0 to 200 μg kg^-1. The analysis by HPTLC/electrospray (ESI)-MS in negative mode confirmed the presence of TCT-B and ZEA standards in Chilean cereals with mass signals at m/z 355, 371, 337, and 317 for DON, NIV, 3-ADON and 15-ADON, and ZEA, respectively.

Greenness profile assessment of selective liquid chromatographic methods for determination of a quaternary antimigraine combination along with three of their related official impurities

Two selective, sensitive and environmentally safe LC methods were developed and validated for determination of paracetamol, caffeine, ergotamine tartrate and metoclopramide in coformulated antimigraine tablets along with p-aminophenol, p-nitrophenol and theophylline as officially specified impurities. The first is based on high-performance thin-layer chromatography (HPTLC) coupled with densitometric quantitation. Separation was achieved on HPTLC silica gel 60 F₂₅₄ plates as stationary phase using ethyl acetate:aqueous ammonium hydroxide solution:glacial acetic acid (10.0:0.4:0.1, by volume) as a developing system followed by scanning of the separated bands at 210.0 nm. The subsequent method depends on HPLC with diode array detection. The LC separation was accomplished on a Scharlau C₁₈ (250 × 4.6 mm, 5 μm) column using a mixture of 20.0 mm sodium dihydrogen phosphate, pH 3.0, adjusted with o-phosphoric acid and methanol, at a flow rate of 1.3 mL/min in a gradient elution program. The separated peaks were detected at 210.0 nm. The proposed methods have been validated and proven to meet the requirements outlined in the International Council for Harmonisation (ICH) guidelines. The greenness profile evaluation was carried out using three tools, namely, the National Environmental Method Index, the Analytical EcoScale and the Green Analytical Procedure Index tool, and a comparative study was then conducted. Successful application of the developed methods for determination of the cited quaternary mixture in Metograine tablets confirms their suitability regarding the analytical performance and ecological impact in quality control assay and impurity profiling purposes.

A comparative study of two analytical techniques for the simultaneous determination of amprolium HCl and ethopabate from combined dosage form and in presence of their alkaline degradation

Chemometric and separation-based techniques (HPLC) are the most applicable and versatile analytical techniques for the analysis of multicomponent mixtures, in the present contribution, a comparison was highlighted between the two analytical techniques of utmost importance as stability indicating assays: UV-spectrophotometry and HPLC-UV focusing on the greenness of each for the simultaneous determination of amprolium HCl (AMP) and ethopabate (ETHOP) in the presence of their alkaline degradation products. The first method was chemometric methods applied were PLS-1, GA-PLS and GA-ANN. To compare the prediction ability of the models, a 4-factor 5-level experimental design was used to establish a calibration set of 25 mixtures containing different ratios of the drugs and their degradation products. The validity of the proposed methods was assessed using an independent validation set of 5 mixtures. The comparison between the different models showed the superiority of ANN model in solving the highly overlapped spectra of the quaternary mixture, yet using inexpensive and easy to handle instruments like the UV-VIS spectrophotometer. The ANN method was used for the quantitative analysis of the drugs in pharmaceutical dosage form via handling the UV spectral data. The second method was based on liquid chromatographic HPLC determination of AMP and ETHOP using C18 column (250 × 4.6 mm²)-PRONTOSIL 5 μm, a mobile phase consisting of methanol: Hexane sulphonic acid sodium salt at (pH = 3.4 ± 0.2) adjusted by orthophosphoric acid (55: 45 v/v). Quantitation was achieved with UV detection at 270 nm at temperature 24 °C. Linearity, accuracy and precision were found to be acceptable over the concentration range of 10.0-70.0 and 1.0-25.0 μg·mL^-1 for AMP and ETHOP, respectively. The proposed methods could be successfully applied for the routine analysis of the studied drugs either in their pure bulk powders or in their pharmaceutical preparations without any preliminary separation step. The results obtained were statistically compared with those obtained by applying the reported method.

Stability assessment of tamsulosin and tadalafil co-formulated in capsules by two validated chromatographic methods

The advent of a new pharmaceutical formulation evokes the need for examining the chemical stability of their constituents and establishing proper stability-indicating methods. Herein, the stability of the newly co-formulated Tamsulosin and Tadalafil were examined under different stress conditions. The acidic degradation of Tamsulosin yielded its sulfonated derivative, while Tadalafil was susceptible to both acidic and basic degradation. Two stability-indicating chromatographic methods, namely; high-performance thin-layer chromatography and high-performance liquid chromatography, have been developed. Significant high-performance thin-layer chromatography-fractionation could be achieved by utilizing a stationary phase of silica gel 60 F₂₅₄ and a mobile phase composed of ethyl acetate/toluene/methanol/ammonia (4:2:4:0.6, by volumes) with densitometric recording at 280 nm over a concentration range of 0.5-25 μg/band for both drugs. The HPLC-separation could be reached on XBridge^® C₁₈ column isocraticaly by using a mobile phase having acetonitrile/phosphate buffer, pH 6.0 (45:55, v/v) pumped at a flow rate of 1.7 mL/min and applying diode array ultraviolet-detection at 210 nm over a linearity range of 3-70 μg/mL for each drug. Specificity of the two methods was additionally assured via peak purity assessment. Moreover, the methods were distinctly exploited for evaluating the drugs' stability in accelerated stability-studied samples of Tamplus^® capsules.

Stepwise optimization and sensitivity improvement of green micellar electrokinetic chromatography method to simultaneously determine some fluoroquinolones and glucocorticoids present in various binary ophthalmic formulations

A sensitive micellar electrokinetic chromatography method is presented to simultaneously quantify ofloxacin, gatifloxacin, dexamethasone sodium phosphate and prednisolone acetate. The method has the advantages of being rapid, accurate, reproducible, ecologically acceptable and sensitive. The electrophoretic separation utilized 20 mm borate buffer as background electrolyte with pH 10.0 ± 0.1 and 50 mm sodium dodecyl sulfate as a micelle forming molecule. A capillary tube (50 μm i.d., 33 cm) of fused silica was used and on-column diode array detection at 243 nm for dexamethasone sodium phosphate and prednisolone acetate, and 290 nm for ofloxacin and gatifloxacin. Various factors were optimized such as the background electrolyte (type, concentration and pH), addition of sodium dodecyl sulfate and its concentration, detection wavelength, applied voltage and injection parameters. The studied drugs were efficiently separated in 6.2 min, at 20 kV with high resolution. The greenness of the method was estimated using an eco-scale tool and the presented method was found to have excellent green characteristics. The method was validated in conformance with International Conference on Harmonization guidelines, with acceptable accuracy, precision and selectivity. The suggested method can be employed for the economic analysis of the four drugs in dissimilar binary combinations of eye drops saving solvents and chemicals.

Simultaneous Determination of 6-Shogaol and 6-Gingerol in Various Ginger (Zingiber officinale Roscoe) Extracts and Commercial Formulations Using a Green RP-HPTLC-Densitometry Method

Various analytical methodologies have been reported for the determination of 6-shogaol (6-SHO) and 6-gingerol (6-GIN) in ginger extracts and commercial formulations. However, green analytical methods for the determination of 6-SHO and 6-GIN, either alone or in combination, have not yet been reported in literature. Hence, the present study was aimed to develop a rapid, simple, and cheaper green reversed phase high-performance thin-layer chromatography (RP-HPTLC) densitometry method for the simultaneous determination of 6-SHO and 6-GIN in the traditional and ultrasonication-assisted extracts of ginger rhizome, commercial ginger powder, commercial capsules, and commercial ginger teas. The simultaneous analysis of 6-SHO and 6-GIN was carried out via RP-18 silica gel 60 F254S HPTLC plates. The mixture of green solvents, i.e., ethanol:water (6.5:3.5 v/v) was utilized as a mobile phase for the simultaneous analysis of 6-SHO and 6-GIN. The analysis of 6-SHO and 6-GIN was performed at λmax = 200 nm for 6-SHO and 6-GIN. The densitograms of 6-SHO and 6-GIN from traditional and ultrasonication-assisted extracts of ginger rhizome, commercial ginger powder, commercial capsules, and commercial ginger teas were verified by obtaining their single band at Rf = 0.36 ± 0.01 for 6-SHO and Rf = 0.53 ± 0.01 for 6-GIN, compared to standard 6-SHO and 6-GIN. The green RP-HPTLC method was found to be linear, in the range of 100-700 ng/band with R2 = 0.9988 for 6-SHO and 50-600 ng/band with R2 = 0.9995 for 6-GIN. In addition, the method was recorded as "accurate, precise, robust and sensitive" for the simultaneous quantification of 6-SHO and 6-GIN in traditional and ultrasonication-assisted extracts of ginger rhizome, commercial ginger powder, commercial capsules, and commercial ginger teas. The amount of 6-SHO in traditional extracts of ginger rhizome, commercial ginger powder, commercial capsules, and commercial ginger teas was obtained as 12.1, 17.9, 10.5, and 9.6 mg/g of extract, respectively. However, the amount of 6-SHO in ultrasonication-assisted extracts of ginger rhizome, commercial ginger powder, commercial capsules, and commercial ginger teas were obtained as 14.6, 19.7, 11.6, and 10.7 mg/g of extract, respectively. The amount of 6-GIN in traditional extracts of ginger rhizome, commercial ginger powder, commercial capsules, and commercial ginger teas were found as 10.2, 15.1, 7.3, and 6.9 mg/g of extract, respectively. However, the amount of 6-GIN in ultrasonication-assisted extracts of ginger rhizome, commercial ginger powder, commercial capsules, and commercial ginger teas were obtained as 12.7, 17.8, 8.8, and 7.9 mg/g of extract, respectively. Overall, the results of this study indicated that the proposed analytical technique could be effectively used for the simultaneous quantification of 6-SHO and 6-GIN in a wide range of plant extracts and commercial formulations.

A Green RP-HPTLC-Densitometry Method for the Determination of Diosmin in Pharmaceutical Formulations

Green analytical technologies for the determination of a bioactive compound diosmin (DIOM) in the real samples of pharmaceutical formulations and biological fluids are scarce in literature. Therefore, the present investigation was carried out to develop a novel, rapid, simple, and economical green “reversed phase high-performance thin-layer chromatography (RP-HPTLC)” method for the determination of DIOM in commercial tablets and in-house developed spray-dried microparticles (MPs). The quantification of DIOM was conducted via “RP-18 silica gel 60 F254S HPTLC plates”. The binary combination of green solvents, i.e., ethanol:water (5.5:4.5 v/v) was proposed as a green mobile phase. The analysis of DIOM was conducted in absorbance/reflectance mode of densitometry at λmax = 348 nm. The densitograms of DIOM from the commercial tablets and in-house developed spray-dried MPs were verified by recording their single band at Rf = 0.80 ± 0.02 compared to standard DIOM. Green RP-HPTLC method was observed as linear in the range of 100–700 ng/band with R2 = 0.9995. The proposed method was found as “accurate, precise, robust, and sensitive” for the determination of DIOM in the real samples of commercial tablets and in-house developed spray-dried MPs. The % content of DIOM in the real samples of commercial tablets and in-house developed spray-dried MPs was obtained as 99.06 and 101.30%, respectively. The recorded results of this research suggested that the green RP-HPTLC method can be effectively used for the routine analysis of DIOM in pharmaceutical products.

Determination of Delafloxacin in Pharmaceutical Formulations Using a Green RP-HPTLC and NP-HPTLC Methods: A Comparative Study

In this work; delafloxacin (DLFX) was determined using a validated green RP-HPTLC and NP-HPTLC methods in commercial tablets and in-house developed solid lipid nanoparticles (SLNs). RP-HPTLC determination of DLFX was performed using "RP-18 silica gel 60 F254S HPTLC plates". However; NP-HPTLC estimation of DLFX was performed using "silica gel 60 F254S HPTLC plates". For a green RP-HPTLC method; the ternary combination of ethanol:water:ammonia solution (5:4:2 v/v/v) was used as green mobile phase. However; for NP-HPTLC method; the ternary mixture of ethyl acetate: methanol: ammonia solution (5:4:2 v/v/v) was used as normal mobile phase. The analysis of DLFX was conducted in absorbance/reflectance mode of densitometry at λmax = 295 nm for both methods. RP-HPTLC method was found more accurate, precise, robust and sensitive for the analysis of DLFX compared with the NP-HPTLC method. The % assay of DLFX in commercial tablets and in-house developed SLNs was determined as 98.2 and 101.0%, respectively, using the green RP-HPTLC technique, however; the % assay of DLFX in commercial tablets and in-house developed SLNs was found to be 94.4 and 95.0%, respectively, using the NP-HPTLC method. Overall, the green RP-HPTLC method was found superior over the NP-HPTLC. Therefore, the proposed green RP-HPTLC method can be successfully applied for analysis of DLFX in commercial tablets, SLNs and other formulations containing DLFX.

Ecofriendly densitometric RP-HPTLC method for determination of rivaroxaban in nanoparticle formulations using green solvents

A literature survey revealed no suitable “reversed phase-high performance thin layer chromatography (RP-HPTLC)” method for the analysis of rivaroxaban in nanoparticle (NP) formulations. Therefore, a novel rapid, simple, economical and environment friendly RP-HPTLC method has been established for the quantification of rivaroxaban in NP formulations and commercial tablets. RP-HPTLC analysis of rivaroxaban was performed using “RP-18 silica gel 60 F254S HPTLC plates”. The binary mixture of green solvents ethanol : water (7 : 3 v/v) was utilized as the mobile phase. The quantification of rivaroxaban was carried out in densitometric mode at λ_max = 253 nm. Rivaroxaban peaks from NP formulations was confirmed by comparing its single spot at R_f = 0.71 ± 0.02 with that of the standard. The proposed RP-HPTLC method was found to be linear in the range of 50–600 ng per band with R² = 0.9994. The equation for linear regression analysis was obtained as Y = 13.28x + 1189.4. The proposed RP-HPTLC technique was validated for “precision, accuracy, robustness and sensitivity”. The accuracy of the method was obtained as 97.97–99.67%. The % RSD in repeatability and intermediate precision was recorded as 0.46–0.64 and 0.48–0.86%, respectively. The LOD and LOQ for rivaroxaban were obtained as 18.45 and 55.35 ng per spot, respectively. The % content of rivaroxaban in marketed tablets and NPs was recorded as 99.20 and 98.08%, respectively. The proposed RP-HPTLC technique could be successfully applied for the pharmaceutical assay of rivaroxaban in NPs, marketed tablets and related formulations.

A literature survey revealed no suitable “reversed phase-high performance thin layer chromatography (RP-HPTLC)” method for the analysis of rivaroxaban in nanoparticle (NP) formulations.