Green RP-HPLC method for simultaneous determination of moxifloxacin combinations: Investigation of the greenness for the proposed method

Green HPLC Enantioseparation of Chemopreventive Chiral Isothiocyanates Homologs on an Immobilized Chiral Stationary Phase Based on Amylose tris-[(S)-α-Methylbenzylcarbamate]

Sulforaphane is a chiral phytochemical with chemopreventive properties. The presence of a stereogenic sulfur atom is responsible for the chirality of the natural isothiocyanate. The key role of sulfur chirality in biological activity is underscored by studies of the efficacy of individual enantiomers as chemoprotective agents. The predominant native (R) enantiomer is active, whereas the (S) antipode is inactive or has little or no biological activity. Here we provide an enantioselective high-performance liquid chromatography (HPLC) protocol for the direct and complete resolution of sulforaphane and its chiral natural homologs with different aliphatic chain lengths between the sulfinyl sulfur and isothiocyanate group, namely iberin, alyssin, and hesperin. The chromatographic separations were carried out on the immobilized-type CHIRALPAK IH-3 chiral stationary phase with amylose tris-[(S)-methylbenzylcarbamate] as a chiral selector. The effects of different mobile phases consisting of pure alcoholic solvents and hydroalcoholic mixtures on enantiomer retention and enantioselectivity were carefully investigated. Simple and environmentally friendly enantioselective conditions for the resolution of all chiral ITCs were found. In particular, pure ethanol and highly aqueous mobile phases gave excellent enantioseparations. The retention factors of the enantiomers were recorded as the water content in the aqueous-organic modifier (methanol, ethanol, or acetonitrile) mobile phases progressively varied. U-shaped retention maps were generated, indicating a dual and competitive hydrophilic interaction liquid chromatography (HILIC) and reversed-phase liquid chromatography retention mechanism on the CHIRALPAK IH-3 chiral stationary phase. Finally, experimental chiroptical studies performed in ethanol solution showed that the (R) enantiomers were eluted before the (S) counterpart under all eluent conditions investigated.

Green innovation in analytical chemistry: A sustainable densitometric HPTLC approach for the distinctive separation and quantification of structurally related abused drugs - tramadol, tapentadol, and venlafaxine - in seized pharmaceutical dosage forms

An innovative ecofriendly high-performance thin layer chromatographic (HPTLC) method with spectrophotometric detection for simultaneous determination of Tramadol (TMD), Tapentadol (TAP), and Venlafaxine (VEN) in seized dosage forms was presented. Our method was conducted to achieve separation following the optimal conditions: pre-coated silica gel plates using a green mobile phase (heptane: acetone: ammonia, 7:3:0.5 v/v), with absorbance scanning at 272 nm. The validation of the method was done following International Conference on Harmonization (ICH) guidelines, demonstrates linearity, accuracy, precision, selectivity, robustness, and system suitability. Separation was achieved with a detection limit of 0.34, 0.16, and 0.084 (ug/band) for TMD, TAP, and VEN, respectively, the method successfully analyzes seized samples. Trueness is confirmed through a high degree of similarity between HPTLC and gas chromatography results. The study's ecofriendly approach, simplicity, and selectivity position it as a promising method for efficient, on-site monitoring of seized samples.

Eco-friendly micellar HPLC approach for simultaneous estimation of combination therapy for hidradenitis suppurativa: Applications to spiked human plasma and different dosage forms

This study introduces a new method for analyzing rifampicin, moxifloxacin, and metronidazole using a green micellar High Performance Liquid Chromatography-Ultraviolet method in bulk drugs, different commercial formulations, and spiked human plasma. The combined therapy of these three broad-spectrum antibiotics is used to cure refractory hidradenitis suppurativa (HS), an inflammatory condition affecting the skin. The sustainable separation was attained on a reversed-phase C18 Kinetex® column maintained at ambient temperature in less than 5 min. The mobile phase comprises 0.1 M sodium dodecyl sulfate (SDS) in water, pH 3.5, adjusted using o-phosphoric acid, and 10% n-butanol. The flow rate was 1 mL/min, with 10 μL injection volume and UV detection at 230 nm. The impact of three key significant variables, SDS concentration, n-butanol percentage, and the mobile phase pH, on suitability parameters was studied. ICH and FDA guidelines were committed to when validating the technique. The results showed linear calibration graphs with high precision and accuracy, in both pure and spiked plasma. The method is efficient, easy to use, and has a high sample throughput, making it suitable for routine analysis in the quality control department and therapeutic monitoring. It is also evaluated as a green-and-white substitute for traditional reported methods.

Eco-friendly approach for the determination of moxifloxacin in pharmaceutical formulations and biological fluids based on fluorescence quenching of l-tryptophan

A rapid, novel and cost-effective spectrofluorimetric method developed to determine moxifloxacin (MFX) in pharmaceutical preparations because MFX in a pH 10 medium could reduce the fluorescence intensity of l-tryptophan. The maximum fluorescence excitation and emission wavelengths were found to be 280 and 363 nm respectively. A range of factors affecting fluorescence quenching and the effect of co-existing substances were investigated. Fluorescence quenching values (ΔF = FL-tryptophan  - FMoxi-L-tryptophan ) displayed a strong linear relationship with the MFX concentration ranging from 0.2 to 8.0 μg/ml under optimum conditions. The limit of detection was found to be 6.1 × 10-4  μg/ml. The proposed method was shown to be suitable for MFX determination in pharmaceutical tablets and biological fluids by the linearity, recovery and limit of detection. The spectrofluorimetric approach that has been developed is extremely eco-friendly, as evidenced by the fact that all the experimental components and solvents were safe for the environment.

Validated spectrofluorimetric assay of two co-administered drug mixtures containing hydroxychloroquine with either moxifloxacin or ofloxacin as a drug regimen for hospital-acquired pneumonia in patients with COVID-19

Moxifloxacin and ofloxacin are two broad-spectrum quinolone antibiotics. They are among the most widely used antibiotics, at this time, applied to control the COVID-19 pandemic. Hydroxychloroquine is an FDA-approved drug for the treatment of COVID-19. This work describes a simple, green, selective, and sensitive spectrofluorimetric method for the assay of moxifloxacin and ofloxacin in the presence of hydroxychloroquine, two co-administered mixtures used in the treatment of hospital-acquired pneumonia in patients with COVID-19. Simultaneous assay of hydroxychloroquine and moxifloxacin was carried out in methanol using a direct spectrofluorimetric method (method I) at 375 and 550 nm, respectively, after excitation at 300 nm. The direct spectrofluorimetric assay was rectilinear over concentration ranges 50.0-400.0 and 300.0-2500.0 ng/ml for hydroxychloroquine and moxifloxacin, respectively, with limits of detection (LOD) of 6.4 and 33.64 ng/ml and limits of quantitation (LOQ) of 19.4 and 102.6 ng/ml, respectively, for the two drugs. The assay for hydroxychloroquine and ofloxacin was carried out by measuring the first derivative synchronous amplitude for hydroxychloroquine at the zero crossing point of ofloxacin and vice versa at Δλ = 140 nm (method II). Hydroxychloroquine was measured at 266 nm, while ofloxacin was measured at 340 nm over the concentration range 4-40 ng/ml for hydroxychloroquine and 200-2000 ng/ml for ofloxacin with LOD of 0.467 and 25.3 ng/ml and LOQ of 1.42 and 76.6 ng/ml, respectively, for the two drugs. The two methods were validated following International Conference on Harmonization guidelines and were applied to the analysis of the two drugs in plasma with good percentage recoveries (109.73-93.17%).

Development and Validation of Facile RP-HPLC Method for Simultaneous Determination of Timolol Maleate, Moxifloxacin Hydrochloride, Diclofenac Sodium and Dexamethasone in Plasma, Aqueous Humor and Pharmaceutical Products

The present study aimed to develop a validated RP-HPLC method for the simultaneous determination of timolol maleate (TM), moxifloxacin hydrochloride (MOXI), diclofenac sodium (DS) and dexamethasone (DEXA) in human plasma, bovine aqueous humor and pharmaceutical preparations. The chromatographic separation was studied using the C18 column. The chromatographic conditions, such as composition, pH, the flow rate of mobile phase, the temperature of column, wavelength of absorption and injection volume of the sample, were studied. The method was validated to confirm specificity, linearity and accuracy in accordance with an International Conference on Harmonization guidelines. The optimum conditions for separation included mobile phase 0.05 M monobasic phosphate buffer: acetonitrile (65:35 v/v), pH of buffer adjusted to 6.2 and the flow rate of 1 mL/minute. The optimum temperature of the column was found to be 35°C, absorption wavelength 265 nm and injection volume 50 μL. The baseline separation of all four drugs with good sensitivity, resolution, and a less than 15 min run time was achieved. The retention time of TM, MOXI, DS and DEXA were 4.3,5.7,9.9 and 13.5 minutes respectively. The limit of detection (LOD) values were 6.2, 4.8, 0.8 and 1.2 ng/mL for TM, MOXI, DS and DEXA, respectively, whereas their respective limit of quantification (LOQ) values was: were 42.6, 26.8, 5.6 and 6.2 ng/mL. The coefficient of variation for intra-day and inter-day were in the range of 0.32-1.57 and 1.29-3.07%, respectively. The method was found to be sensitive, precise and accurate in human plasma and bovine aqueous humor and can be applied for the quantification of these compounds in plasma, aqueous humor and pharmaceuticals.

Moxifloxacin: Physical-chemical and Microbiological Analytical Methods in the Context of Green Analytical Chemistry

Moxifloxacin (MOX) is a fourth-generation fluoroquinolone used in the form of tablets, infusion solutions and ophthalmic solutions. It does not have a physical-chemical or microbiological analytical method described in an official compendium. However, the literature shows some analysis methods for pharmaceuticals and biological matrices. In this context, the objective is to show the analytical methods present in the literature for the investigation of MOX by physical-chemical and microbiological techniques, as well as discussing them according to the requirements of current pharmaceutical analyses and green analytical chemistry. Among the physical-chemical methods present in the literature for MOX evaluation, 33% are HPLC, 21% are UV-Vis and 17% are capillary electrophoresis. On the other hand, among the microbiological methods, all of them are based on diffusion in agar. There is still scope in the literature to incorporate new and improved analytical methods for MOX evaluation, which adopt the concepts of green and sustainable analytical chemistry, either by using less (or not using) toxic organic solvents, reducing waste generation or even reducing the analysis time according to the intended objectives.

Implementation of HILIC-UV technique for the determination of moxifloxacin and fluconazole in raw materials and pharmaceutical eye gel

Hydrophilic interaction liquid chromatography (HILIC) has inherent merits over RP-HPLC in the analyzing of hydrophilic substances. Accordingly, an innovative HILIC-UV methodology is proposed for the simultaneous estimation of ethyl paraben (PRN), fluconazole (FLZ) and moxifloxacin hydrochloride (MOX) in raw materials and pharmaceutical eye gel. The separation process was conducted using Waters XBridge™ HILIC column (100 mm × 4.6 mm, 3.5 μm particle size) at room temperature. Isocratic mobile phase containing acetonitrile: 0.1% triethylamine buffer (90:10, v/v, pH 5.0), was pumped at flow rate 1.0 mL/min and detected at 260 nm. Under these optimized conditions, PRN, FLZ and MOX showed rectilinear relationships with the concentration ranges (0.5–6.0), (5.0–50.0) and (5.0–60.0) μg/mL, respectively. The developed method offered at least fivefold increase in sensitivity within shorter time than the reported methods. Three greenness assessment tools namely: Analytical eco-scale, GAPI and AGREE were exploited to investigate the method's impact on the environment and conduct a comparative study with the reported methods. International council of Harmonization (ICH) guidelines have been followed to calculate validation parameters. The statistical comparison between results of the suggested method and the comparison method showed no discrepancy confirming accuracy of the method.

Comparative Greenness Metric Estimates for Content Uniformity Testing of Anti-Cov-2, GS-5734 in Commercial Vials: Validated Micellar Electrokinetic Chromatographic Assay

Background

The antiviral drug GS-5734 remdesivir is a new phosphoramidate prodrug developed initially as a treatment for Ebola virus which then proved to have antiviral properties against other viruses. After clinical trials, it was the first antiviral to be approved by the U.S. Food and Drug Administration in 2020 to treat severe coronavirus (COVID-19) cases. The widespread current pandemic gave an urge to its fast production and marketing. Thus, new analytical methods must be available for its analysis in a fast and easy manner with low cost to be applicable in all laboratories.

Objective

In the current study, a green and economic micellar electrokinetic chromatographic (MEKC) method is proposed for remdesivir analysis.

Methods

A fused-silica capillary (58.5 cm × 50 μm id, 50 cm effective length) with 20 mM borate buffer (pH 9) and 25 mM sodium dodecyl sulfate was used under a positive potential of 30 kV at 25°C with detection at 245 nm.

Results

Remdesivir analysis was achieved in approximately 5 min. The method proved to be linear in range of 1–50 μg/mL with correlation coefficient, r > 0.999.

Conclusion

The MEKC method proposed was applied to the analysis of remdesivir in its commercial vials. The method was validated per International Conference on Harmonization guidelines.

Highlights

Green chemistry has been the focus of the analytical community in the past few years. This method is considered green due to its low energy and solvent consumption without sacrificing the method’s sensitivity or selectivity. The method’s green profile has been assessed by different greenness assessment scales to ensure the method is eco-friendly and can be used in the pharmaceutical industry.

A Simple, Cost-Effective, and Green HPTLC Method for the Estimation of Ascorbic Acid in Solvent and Ultrasound-Assisted Extracts of Phyllanthus emblica, Capsicum annuum, and Psidium guajava

Greener analytical methodologies for the estimation of ascorbic acid (AA) are poorly reported in the literature. Furthermore, the green indexes of the literature’s analytical assays of AA estimation have not been assessed. As a consequence, the aim of this research is to invent and validate a simple, cost-effective, and green reverse-phase “high-performance thin-layer chromatography (HPTLC)” method for the estimating AA in the solvent extracts (SE) and ultrasound-assisted extracts (UAE) of Phyllanthus emblica, Psidium guajava, and Capsicum annuum. The greener mobile phase for AA estimation was a binary mixture of water and ethanol (70:30, v/v). At a wavelength of 265 nm, the detection of AA was carried out. The greener HPTLC technique was linear in the 25–1200 ng/band range. In addition, the method was simple, cost-effective, accurate, precise, robust, sensitive, and green. The amount of AA was highest in the SE and UAE of P. emblica compared to the SE and UAE of P. guajava and C. annuum. The amount of AA in the SE of P. emblica, P. guajava, and C. annuum was found to be 491.16, 168.91, and 144.30 mg/100 g, respectively. However, the amount of AA in the UAE of P. emblica, P. guajava, and C. annuum was found to be 673.02, 218.71, and 199.30 mg/100 g, respectively. Using the “analytical GREEnness (AGREE)” methodology, the greenness index for the developed method was calculated to be 0.88, showing that the developed method has an excellent green profile. When it came to extracting AA, the UAE method outperformed the SE method. These findings suggested that the developed method might be used to estimate the AA in a variety of vegetable crops, plant-based extracts, and commercial formulations. Furthermore, because of the use of greener solvent systems against the commonly utilized hazardous solvent systems for AA determination, this technique is also safe and sustainable.

A Green High-Performance Thin-Layer Chromatography Method for the Determination of Caffeine in Commercial Energy Drinks and Formulations

The literature on green analytical approaches for caffeine estimation is limited. As a consequence, this study aimed to establish a reverse-phase high-performance thin-layer chromatography (HPTLC) technique for caffeine estimation in a variety of commercial energy drinks (ED) and pharmaceutical formulations that is rapid, sensitive, and green. The combination of ethanol-water (55:45 v v−1) was used as a mobile phase. The detection of caffeine was carried out at 275 nm. The green reverse-phase HPTLC method was linear in the concentration range of 50−800 ng band−1. Furthermore, the developed method for caffeine estimation was simple, quick, economical, accurate, precise, robust, sensitive, and green. The amount of caffeine in different marketed ED (ED1−ED10) was recorded in the range of 21.02−37.52 mg 100 mL−1 using the developed HPTLC method. However, the amount of caffeine in different commercial formulations (F1−F3) was estimated as 10.63−20.30 mg 100 mL−1 using the same method. The “analytical GREEnness (AGREE)” scale for the developed analytical method was predicted to be 0.80, utilizing 12 distinct components of green analytical chemistry, indicating the HPTLC approach’s excellent greener profile. Overall, the developed method for estimating caffeine in marketed ED and dosage forms was found to be reliable.

Green NP-HPTLC and green RP-HPTLC methods for the determination of thymoquinone: A contrast of validation parameters and greenness assessment

INTRODUCTION

Thymoquinone (TQ) is a naturally derived bioactive compound with several therapeutic effects.

OBJECTIVE

The highly sensitive, rapid and green normal-phase (NP)/reversed-phase (RP) high-performance thin-layer chromatography (HPTLC) densitometry technique was developed for the determination of TQ in various plant extracts of different geographical regions, commercial capsules, creams and essential oils.

METHODOLOGY

The NP densitometry estimation of TQ was performed using a cyclohexane-ethyl acetate (90:10, v/v) green solvent system, while, the RP-densitometry estimation of TQ was performed using an ethanol-water (80:20, v/v) green solvent system. The estimation of TQ was conducted at 259 nm.

RESULTS

The NP and RP densitometry techniques were observed linear in the range of 25-1000 and 50-600 ng/band, respectively. All validation parameters such as accuracy, precision, robustness and sensitivity of NP/RP densitometry were observed within the limit of regulatory requirements and hence found to be suitable for the determination of TQ. The TQ contents were found to be highest in the Saudi Arabian extract followed by the Syrian extract, Indian extract, commercial capsules, commercial creams, Jordanian extract, Egyptian extract, Palestinian extract and commercial essential oils using NP densitometry. The TQ contents were found in same order using RP densitometry, but they were much lower than those recorded using NP densitometry. The Analytical GREEnness (AGREE) scores of NP and RP densitometry were found to be 0.82 and 0.84, respectively, suggesting an excellent greenness profile.

CONCLUSIONS

Based on these results, NP/RP densitometry was found to be suitable for the pharmaceutical assay of TQ.

A Greener Stability-Indicating High-Performance Thin-Layer Chromatography Approach for the Estimation of Topiramate

Despite various reported analytical methods for topiramate (TPM) analysis, greener analytical approaches are scarce in literature. As a consequence, the objective of the current research is to design a normal-phase stability-indicating high-performance thin-layer chromatography (SI-HPTLC) methodology for TPM analysis in marketed tablet dosage forms that is rapid, sensitive, and greener. TPM was derivatized densitometrically and analyzed at 423 nm in visible mode with anisaldehyde-sulfuric acid as the derivatizing agent. The greener SI-HPTLC technique was linear in the 30–1200 ng band⁻¹ range. In addition, the suggested SI-HPTLC methodology for TPM analysis was simple, rapid, cheaper, precise, robust, sensitive, and environmentally friendly. The greener SI-HPTLC method was able to detect TPM along with its degradation products under acid, base, and oxidative degradation conditions. However, no TPM degradation was recorded under thermal and photolytic stress conditions. TPM contents in commercial tablet dosage forms were recorded as 99.14%. Using 12 different principles of green analytical chemistry, the overall analytical GREEnness (AGREE) score for the greener SI-HPTLC method was calculated to be 0.76, confirming the proposed normal-phase SI-HPTLC method’s good greener nature. Overall, these results demonstrated that the suggested SI-HPTLC technique for TPM measurement in pharmaceutical products was reliable and selective.

Analytical Methods for the Determination of Major Drugs Used for the Treatment of COVID-19. A Review

At the beginning of the COVID-19 outbreak (end 2019 - 2020), therapeutic treatments based on approved drugs have been the fastest approaches to combat the new coronavirus pandemic. Nowadays several vaccines are available. However, the worldwide vaccination program is going to take a long time and its success will depend on the vaccine public's acceptance. Therefore, outside of vaccination, the repurposing of existing antiviral, anti-inflammatory and other types of drugs, have been considered an alternative medical strategy for the COVI-19 infection. Due to the broad clinical potential of the drugs, but also to their possible side effects, analytical methods are needed to monitor the drug concentrations in biological fluids and pharmaceutical products. This review deals with analytical methods developed in the period 2015 - July 2021 to detect potential drugs that, according to a literature survey, have been taken into consideration for the treatment of COVID-19. The drugs considered here have been selected on the basis of the number of articles published in the period January 2020-July 2021, using the combination of the keywords: COVID-19 and drugs or SARS-CoV-2 and drugs. A section is also devoted to monoclonal antibodies. Over the period considered, the analytical methods have been employed in a variety of real samples, such as body fluids (plasma, blood and urine), pharmaceutical products, environmental matrices and food.

Determination of Thymol in Commercial Formulation, Essential Oils, Traditional, and Ultrasound-Based Extracts of Thymus vulgaris and Origanum vulgare Using a Greener HPTLC Approach

In the literature, greener analytical approaches for determining thymol in its commercial formulations, plant-based phytopharmaceuticals, and biological fluids are scarce. As a result, the goal of this study is to develop and validate a normal-phase "high-performance thin-layer chromatography (HPTLC)" method for determining thymol in commercial formulations, essential oils, traditional extracts (TE), and ultrasound-based extracts (UBE) of Thymus vulgaris and Origanum vulgare obtained from various geographical regions. The greener mobile phase for thymol analysis was a binary combination of cyclohexane and ethyl acetate (85:15, v/v). The derivatized densitometric analysis of thymol was carried out under visible mode at 530 nm utilizing anisaldehyde-sulfuric acid as a derivatizing/visualizing agent. In the 10-2000 ng/band range, the greener normal-phase HPTLC method was linear. Furthermore, for thymol analysis, the proposed analytical approach was simple, quick, inexpensive, accurate, precise, robust, sensitive, and greener. The thymol contents in commercial formulation were computed as 7.61% w/w. In general, the thymol contents were maximum in essential oils of T. vulgaris and O. vulgare compared to the other sample matrices studied. The thymol contents of TE of T. vulgaris and O. vulgare of different geographical regions were significantly low compared to their UBE extract. Using 12 distinct components of green analytical chemistry, the overall "analytical GREEnness (AGREE)" scale for the proposed analytical approach was computed 0.79, showing the good greener nature of the proposed analytical approach. Overall, the greener normal-phase HPTLC technique was found to be reliable for determining thymol in commercial formulations and plant-based phytopharmaceuticals.

A Greener HPTLC Approach for the Determination of β-Carotene in Traditional and Ultrasound-Based Extracts of Different Fractions of Daucus carota (L.), Ipomea batatas (L.), and Commercial Formulation

Various analytical approaches for determining β-carotene in vegetable crops and commercial dosage forms have been documented. However, neither the qualitative nor quantitative environmental safety and greener aspects of the literature analytical methodologies of β-carotene analysis have been assessed. As a result, the goal of this research is to develop and validate a reversed-phase “high-performance thin-layer chromatography (HPTLC)” approach for determining β-carotene in traditional (TE) and ultrasound-assisted (UBE) extracts of different fractions of Daucus carota (L.), Ipomea batatas (L.), and commercial formulation. The greener mobile phase for β-carotene analysis was a ternary mixture of ethanol, cyclohexane, and ammonia (95:2.5:2.5, v v v−1). The detection of β-carotene was done at a wavelength of 459 nm. In the 25–1000 ng band−1 range, the greener reversed-phase HPTLC approach was linear. Other validation factors for β-carotene analysis, including as accuracy, precision, robustness, and sensitivity, were likewise dependable. The contents of β-carotene were found to be maximum in hexane: acetone (50:50%) fractions of TE and UBE of D. carota and I. batatas compared to their acetone and hexane fractions. The amount of β-carotene in hexane: acetone (50:50%) portions of TE of D. carota, I. batatas and commercial formulation A was estimated to be 10.32, 3.73, and 6.73 percent w w−1, respectively. However, the amount of β-carotene in hexane: acetone (50:50%) portions of UBE of D. carota, I. batatas and commercial formulation A was estimated to be 11.03, 4.43, and 6.89 percent w w−1, respectively. The greenness scale for the proposed HPTLC strategy was calculated as 0.81 using the “analytical GREEnness (AGREE)” method, indicating that the proposed HPTLC methodology has good greenness. The UBE approach for extracting β-carotene outperformed the TE procedure. These results indicated that the greener reversed-phase HPTLC approach can be utilized for the determination of β-carotene in different vegetable crops, plant-based phytopharmaceuticals, and commercial products. In addition, this approach is also safe and sustainable due to the utilization of a greener mobile phase compared to the toxic mobile phases utilized in literature analytical approaches of β-carotene estimation.

Highly Sensitive and Ecologically Sustainable Reversed-Phase HPTLC Method for the Determination of Hydroquinone in Commercial Whitening Creams

Hydroquinone (HDQ) is a natural depigmenting agent, which is commonly used in skin-toning preparations. The safety and greenness of analytical methods of HDQ quantification were not considered in previous literature. Therefore, a highly sensitive and ecologically greener reversed-phase high-performance thin-layer chromatography (RP-HPTLC)-based assay was established for HDQ estimation in four different commercial whitening creams (CWCs). The binary ethanol–water (60:40, v·v−1) mixture was utilized as the green solvent system. The estimation of HDQ was carried out at 291 nm. The present RP-HPTLC-based assay was linear in the 20–2400 ng band−1 range. The present analytical method was highly sensitive based on the detection and quantification data. The other validation parameters, such as accuracy, precision, and robustness, were also suitable for the determination of HDQ. Maximum HDQ quantities were obtained in CWC A (1.23% w·w−1) followed by CWC C (0.81% w·w−1), CWC D (0.43% w·w−1), and CWC B (0.37% w·w−1). The analytical GREEnness (AGREE) score for the present analytical method was estimated as 0.91, indicating the excellent greener characteristics of the present RP-HPTLC assay. These results suggest that the present analytical method is highly sensitive and ecologically sustainable for the quantitation of HDQ in its commercial formulations.

Eco-Friendly UPLC-MS/MS Quantitation of Delafloxacin in Plasma and Its Application in a Pharmacokinetic Study in Rats

A novel UPLC-MS/MS assay was developed for rapid quantification of delafloxacin (a novel fluoroquinolone antibiotic in plasma samples by one step sample cleanup procedure. Delafloxacin (DFX) and internal standard (losartan) were separated on a UPLC BEH C18 column (50 × 2.1 mm; 1.7 μm) by using gradient programing of a mobile phase containing 0.1% formic acid in acetonitrile and 0.1% formic acid in water. The quantification was performed by a using triple-quadrupole mass detector at an electrospray ionization interface in positive mode. The precursor to the product ion transition of 441.1 → 379.1 for the qualifier and 441.1 → 423.1 for the quantifier was used for DFX monitoring, whereas 423.1 → 207.1 was used for the internal standard. The validation was performed as per guidelines of bioanalytical method validation, and the evaluated parameters were within the acceptable range. The greenness assessment of the method was evaluated by using AGREE software covering all 12 principles of green analytical chemistry. The final score obtained was 0.78, suggesting excellent greenness of the method. Moreover, Deming regression analysis showed an excellent linear relationship between this method and our previously reported method, and it is suitable for high-throughput analysis for routine application. The proposed method was effectively applied in a pharmacokinetic study of novel formulation (self-nanoemulsifying drug delivery systems) of DFX in rats.

A Sustainable Reversed-Phase HPTLC Method for the Quantitative Estimation of Hesperidin in Traditional and Ultrasound-Assisted Extracts of Different Varieties of Citrus Fruit Peels and Commercial Tablets

Hesperidin (HSP) is a bioactive flavanone glycoside, present abundantly in the variety of citrus fruits. The environmental safety and sustainability of the reported analytical assays of HSP analysis have not been considered in the literature. Hence, a sensitive and sustainable “reversed-phase high-performance thin-layer chromatography (RP-HPTLC)” method has been developed and validated for HSP analysis in traditional (TE) and ultrasound-based (UBE) extracts of four different varieties of citrus fruit peels and its commercial tablet dosage forms. The binary combination of green solvents such as ethanol-water (50:50, v v−1) was used as the mobile phase. The detection of HSP was performed at 287 nm. The sustainable RP-HPTLC method was linear in 20–2000 ng band−1 range. The studied validation parameters, including accuracy, precision, robustness, sensitivity were acceptable for HSP analysis. The content of HSP in TE of four different varieties of citrus fruits including grapefruit peels (Citrus paradisi), mosambi peels (Citrus limetta), lemon peels (Citrus lemon), and orange peels (Citrus sinensis) was detected as 8.26, 6.94, 5.90, and 6.81% w w−1, respectively. The content of HSP in TE of commercial formulations A and B was detected as 5.31 and 5.55% w w−1, respectively. However, the content of HSP in UBE of grapefruit peels, mosambi peels, lemon peels, and orange peels was detected as 11.41, 8.86, 7.98, and 8.64% w w−1, respectively. The content of HSP in UBE of commercial formulations A and B was detected as 6.72 and 6.92% w w−1, respectively. The greenness score of the sustainable RP-HPTLC method was predicted as 0.83 using analytical GREEnness (AGREE) metric approach, indicated the excellent greenness profile of the RP-HPTLC method. UBE procedure for HSP was superior over its TE procedure. These observations and results suggested that the present RP-HPTLC method can be successfully used for the quantitative estimation of HSP in the variety of citrus fruit peels and its commercial formulations. In addition, this method is simple, rapid, precise, accurate, and economical compared to the reported analytical methods of HSP analysis. It is also safe and sustainable method due to the use of ethanol-water solvents systems, as both the solvents are green solvents compared to the solvents used in reported analytical methods of HSP analysis.

Simultaneous enantio- and diastereo-selective high-performance liquid chromatography separation of paroxetine on an immobilized amylose-based chiral stationary phase under green reversed-phase conditions

A simple and green high-performance liquid chromatography method for the separation of paroxetine from its enantiomeric and diastereomeric impurities has been developed. The simultaneous chromatographic resolution was carried out on the amylose-based Chiralpak IA-3 chiral stationary phase using the mixture ethanol-water-diethylamine 80:20:0.1 (v/v/v) as a mobile phase. The effects of substitution of ethanol with methanol or acetonitrile and changes in column temperature on selectivity have been carefully investigated. The optimized single-run HPLC protocol allows the baseline separation of the enantiomers of paroxetine without suffering from interference from five other chiral and achiral impurities reported in the monograph of the European Pharmacopoeia.

Determination of six drugs used for treatment of common cold by micellar liquid chromatography

The use of organic solvents as eluants in RP-HPLC has an important role to decrease retention time and improve peak shape; however, it has high environmental impacts. Their production and disposal represent economic and biohazard problems. So, alternatives had to be introduced and studied to minimize such pollution. Combination of sodium dodecyl sulfate (SDS) together with polyoxyethylene-23-lauryl ether (Brij-35) was studied as an alternative to the presence of organic solvents on the separation performance of six active pharmaceutical ingredients. Response surface methodology was applied to test the impact of three independent variables; concentrations of SDS and Brij-35, as well as, pH of the mobile phase; on retention, peak symmetry, and resolution of the analytes using a rotatable central composite design. Significant variables were determined and the suggested models for predicting retention and resolution parameters were significant. Meanwhile, the common cold is the most abundant disease treated with over-the-counter (OTC) medications worldwide. In 2015, the USA recorded $9.56 billion total sales of OTC cold and cough medicaments alone, with average individual patient expenditure of $338. The worldwide sales and generics of common cold and cough products keep growing annually. The six active pharmaceutical molecules under study, namely, paracetamol, guaifenesin, pseudoephedrine, ibuprofen, chlorpheniramine, and dextromethorphan, are widely used in common cold products. The predicted optimum conditions were validated using mobile phase consisting of 93.6 mM SDS, 32.0 mM Brij-35, and 10.0 mM sodium dihydrogen phosphate, adjusted at pH 5.2, column temperature 35° C, and detection at 215-nm wavelength. The method was successfully applied to determine 12 different combination formulae of the analytes in their pharmaceutical products and was assessed for greenness on two novel metrics. A thorough comparison to previously reported methods was included and methods were assessed against greenness metrics Green Analytical Procedure Index and Analytical Greenness Metric to demonstrate superiority.

Combining Normal/Reversed-Phase HPTLC with Univariate Calibration for the Piperine Quantification with Traditional and Ultrasound-Assisted Extracts of Various Food Spices of Piper nigrum L. under Green Analytical Chemistry Viewpoint

Due to unavailability of sustainable analytical techniques for the quantitation of piperine (PPN) in food and pharmaceutical samples, there was a need to develop a rapid and sensitive sustainable analytical technique for the quantitation of PPN. Therefore, the current research presents a fast and highly sensitive normal/reversed-phase high-performance thin-layer chromatography (HPTLC) technique with classical univariate calibration for the quantitation of PPN in various food spices of black pepper with traditional (TE) and ultrasound-assisted extracts (UBE) of various food spices of Piper nigrum L. under green analytical chemistry viewpoint. The amount of PPN in TE of four different spices of black pepper-namely BPMH, BPLU, BPSH, and BPPA-was found to be 309.53, 304.97, 282.82, and 232.73 mg g-1, respectively using a sustainable normal-phase HPTLC technique. However, the amount of PPN in UBE of BPMH, BPLU, BPSH, and BPPA was recorded as 318.52, 314.60, 292.41, and 241.82 mg g-1, respectively using a sustainable normal phase HPTLC technique. The greenness of normal/reversed-phase HPTLC technique was predicted using AGREE metric approach. The eco-scale was found to be 0.90, suggested excellent greenness of normal/reversed-phase technique. UBE of PPN was also found to be superior over TE of PPN. Overall, the results of this research suggested that the proposed normal/reversed-phase densitometry technique could be effectively used for the quantitation of PPN in food and pharmaceutical samples.

Quantitative Analysis of Emtricitabine in Dosage Forms Using Green RP-HPTLC and Routine NP-HPTLC Methods-A Contrast of Validation Parameters

In this research, an antiviral drug emtricitabine (ECT) was quantified using the validated green reversed-phase high-performance thin-layer chromatography (RP-HPTLC) and routine normal-phase HPTLC (NP-HPTLC) methods in the marketed oral solutions and capsules. Green RP-HPTLC-densitometry quantification was performed using the acetone/water (70:30, v/v) solvent system as the mobile phase. Routine NP-HPTLC-densitometry quantification was performed using the chloroform/methanol (85:15, v/v) solvent system as the mobile phase. The detection was performed at λmax-285 nm for both of the methods. Both densitometry methods were validated for different parameters. Most of the validation parameters including linearity, precision, accuracy, detection, and quantification limits for the green densitometry method were found to be superior compared to the routine densitometry technique. The ECT contents of commercial oral solution and commercial capsules were found to be 100.85 and 98.27%, respectively, using the green densitometry technique. The ECT contents of oral solutions and capsules were 97.16 and 95.54%, respectively, using the routine densitometry technique. Accordingly, the green densitometry technique was found to be better than the routine densitometry technique for ECT assays. Thus, the green densitometry technique can be successfully applied for the quantitation of ECT in the marketed formulations.

A Critical Review on Analytical Methods for Recently Approved FDC Drugs: Pregabalin and Etoricoxib

Fixed-dose combinations (FDCs) refer to products containing two or more active ingredients combined in a single dosage form. The FDCs are justified because of several advantages. These are a) potentiating therapeutic efficacy, b) reducing the incidences of adverse drug effects, c) having pharmacokinetic advantages, d) reducing pills burden, e) reducing the dose of individual drugs and f) decreasing the drug resistance development. A recently approved FDC of Pregabalin IP (75 mg) and Etoricoxib (60 mg) recommended to control neuropathic chronic back pain. Analytical methods are available for individual quantitation of pregabalin (PGB) and etoricoxib (ETC), but an effective and reliable analytical method has not been reported for their combination. Thus, the objective of this literature survey was to gather information on various analytical instrumental methods used so far for the individual quantitation of PGB and ETC in various matrices. Such data would be useful to the scientific community to develop a novel analytical method for the analysis of recently approved FDC of PGB and ETC. Various scientific databases were explored to meet the objectives, and the information is synchronized. The reported methods are high-performance liquid chromatography (48% & 53%), hyphenated techniques (54% & 21%), spectroscopy (50% & 34%), and high-performance thin-layer chromatography, or thin-layer chromatography (6% & 13%) for pregabalin and etoricoxib, respectively. All these methods were specific and selective for the analysis of individual drugs.

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.

Solvent-free mixed micellar mobile phases: An advanced green chemistry approach for reversed-phase HPLC determination of some antihypertensive drugs

Minimizing the amount of organic solvents without loss in chromatographic performance has been an important step toward greening analytical methodologies. Mobile-phase composition is the key for maintaining separation efficiency in liquid chromatography while decreasing the procedure hazardousness. If sodium dodecyl sulfate is mixed with Brij-35 in the mobile phase, they could be used as a green alternative for using organic modifiers. In this research, the effect of changing the relative amounts of both surfactants was studied on the chromatographic performance and separation efficiency of ten antihypertensive drugs belonging to different categories. The use of surfactants has many advantages including low cost and toxicity, safe environmental disposal, unique selectivity besides high solubilization capabilities. The optimum separation was maintained using a mobile phase (0.01 M Brij-35, 0.08 M sodium dodecyl sulfate and 0.01 M sodium dihydrogen phosphate/pH 5) on reversed-phase C18 core-shell column at flow rate 1.5 mL/min and temperature 30°C. The method was successfully applied for the determination of the drugs in various marketed dosage forms. International Conference of Harmonization guidelines were followed to validate the developed method. Additionally, the method was verified on the Green Analytical Procedure Index in regards to the greenness and found to be an excellent green alternative method.

Moxifloxacin Hydrochloride Electrochemical Detection at Gold Nanoparticles Modified Screen-Printed Electrode

It appeared that either the carbon paste or the screen-printed carbon electrodes that were modified with gold nanoparticles (AuNPs) gave rise to the largest current responses after a rapid screening of various nanomaterials as modifiers of carbon composite electrodes in view of designing an electrochemical sensor for Moxifloxacin Hydrochloride (Moxi). The screen-printed electrode (SPE) support was preferred over the carbon paste one for its ability to be used as disposable single-use sensor enabling the circumvention of the problems of surface fouling encountered in the determination of Moxi. The response of AuNPs modified SPE to Moxi was investigated by cyclic voltammetry (CV) (including the effect of the potential scan rate and the pH of the medium), chronoamperometry, and differential pulse voltammetry (DPV) after morphological and physico-chemical characterization. DPV was finally applied to Moxi detection in phosphate buffer at pH 7, giving rise to an accessible concentration window ranging between 8 µM and 0.48 mM, and the detection and quantification limits were established to be 11.6 µM and 38.6 µM, correspondingly. In order to estimate the applicability of Moxi identification scheme in actual trials, it was practiced in a human baby urine sample with excellent recoveries between 99.8 % and 101.6 % and RSDs of 1.1-3.4%, without noticeable interference.

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.

A Reversed-Phase HPLC Method for Determination of Osteopontin in Infant Formula

Osteopontin (OPN) is a multifunctional whey protein which has recently received much attention for possibly applications in fortifying infant milk formula (IMF) with its bioactivity. However, to date, there is no established high-performance liquid chromatography (HPLC) method to quantify this protein in milk or IMF. In this study, a rapid, simple, isocratic and reliable reversed-phase HPLC method was developed and validated to quantify the OPN in IMF. A C18 column (4.6 × 150 mm × 5 micron) was employed with 20% of 0.1% trifluoroacetic acid (TFA) and 80% of 60% acetonitrile in 0.1% TFA for 10 min detected at 214 nm. The flow rate was 0.3 mL/min with an injection volume of 10 µL. The column temperature was 40 °C, and the peak appeared after 4 min. The validation was based on the system suitability, linearity (r2 = 0.999), limit of detection (LOD) (0.14 mg/L), limit of quantitation (LOQ) (0.41 mg/L), precision (% relative standard deviation (RSD) < 0.2), recovery (% RSD < 3) and robustness. The results confirm that the method developed is suitable for OPN determination in IMF.