Micellar Liquid Chromatographic Method Research Articles

Evaluating the effectiveness of different household washing techniques for removal of insecticides from spinach and chickpea leaves by micellar liquid chromatography

In the past few decades, the employment of green analytical approaches in chromatographic method development has attracted the analytical separation community. The greenness of the developed method depends upon the toxicity of solvents and the amount of generated post-analysis waste generated. In this concern, micellar liquid chromatography (MLC) is a simple and rapid technique that generates very low toxic waste compared to traditional chromatographic pesticide detection methods. Here, MLC method has been validated and applied for the determination of monocrotofos (MCF), imidacloprid (ICP), dimethoate (DM) and profenofos (PFF) in spinach and chickpea leaves. The optimized mobile phase was 0.065 M SDS-2 % 1-propanol, 0.01 M NaH2PO4 buffered to pH 7. A C18 column was used for separation with a flow rate of 1 mL/min. The developed method has been validated following the guidelines of SANTE/11,312/2021 and ICH guidelines for; limit of quantification (0.05–0.20 mg/kg), linearity (r2> 0.997–0.999), precision (<6.3 %), accuracy (96.3 %–99.8 %) and robustness (<6) in real samples. ICP and MCF, apart from DM and PFF, were detected in the present work. After detecting insecticides in spinach and chickpea leaves both were washed with different household chemicals i.e. normal, lukewarm, common salt, lemon juice water and commercial ozonizer. Based on five washing techniques with insecticide concentration time intervals reduction rates were calculated for each washing treatment. The results show that lemon juice, common salt water, and ozonizer can be used as washing techniques for the reduction of superficial and systematic residues of ICP and MCF. Common salt and lemon juice water were better for washing over vinegar and potassium permanganate (KMnO4) as they enhance the colour of the green leafy vegetables and are available in every Indian kitchen. They can be easily used by lower socioeconomic classes who cannot afford KMnO4 and vinegar.

Green micellar liquid chromatographic method for simultaneous determination of antihistaminic drugs tripelennamine hydrochloride and diphenhydramine in pharmaceutical gel.

A new green micellar liquid chromatographic method has been developed and validated for the simultaneous determination of diphenhydramine (DPH) and tripelennamine hydrochloride (TRP) using a micellar mobile phase consisting of 1mM Tween 20 in phosphate buffer pH 4:isopropanol (85:15, %v/v). The method was linear in the range of 4-150 and 5-120μg/mL for TRP and DPH, respectively. The method was successfully applied for the simultaneous determination of DPH and TRP in a laboratory-prepared gel containing all possible excipients with mean percent recoveries±standard deviation of 100.346±1.265 and 100.754±1.117 for TRP and DPH, respectively. The method was validated according to the International Conference on Harmonization guidelines. The method is confirmed to have excellent greenness.

Use of green analysis methods to determine the ionization constant values of isoxazolyl penicillins

In this study, an environmentally friendly analysis of penicillinase-resistant antibiotics oxacillin, dicloxacillin, and cloxacillin was carried out by liquid chromatography methods using ethanol solvent that is not harmful to human health and the environment. Ionization constant (wwpKa) values of isoxazolyl penicillins in ethanol–water binary mixtures containing 20–35% (v/v) ethanol at 37 °C were obtained by green reverse phase liquid chromatography and micellar liquid chromatography methods known as green chromatography. The developed methods are based on a model that relates the chromatographic behavior of the identified analytes to pH. The linear relationship between the microscopic solvatochromic parameter ETN and the retention values of the compounds was determined depending on the change of organic solvent in the mobile phase. Using the obtained chromatographic data, conditions that ensure the simultaneous separation of the compounds for both methods were determined. The relationship between the calculated sspKa values and the macroscopic properties of ethanol was investigated. The agreement between the pKa (wwpKa) values in the water medium determined by this approach was determined by t-test at a 95% confidence level for both methods. The wwpKa values of the compounds at 25 °C were also estimated using Abraham solute parameters without any experimental work.

Micellar Liquid Chromatographic Method for Determination of Moxifloxacin and its Impurities

A selective eco-friendly micellar HPLC method was developed for investigation of moxifloxacin and related compounds in the presence of its degradation products. Central composite design was used to optimize the experimental conditions. The proposed method is based on isocratic elution on a C18 column using 92.5% (v/v) biodegradable aqueous mobile phase containing 0.01 M sodium dihydrogen phosphate, 0.15 M sodium dodecyl sulfate (SDS) and 0.5% triethylamine (v/v) with a pH of 3.5 and 7.5% isopropanol (v/v) as eco- friendly organic solvent. The flow rate and injection volume were 0.6 ml/min and 5 μl, respectively. Experiments were performed at a temperature of 60 °C and detection was performed at 295 nm. The optimized method was validated. The method was found to be suitable for the quantification of moxifloxacin and its related compounds in moxifloxacin drug substance. The Green Analytical Procedure Index (GAPI) proves the superiority of the developed method against other reported methods.

Green method for determination of four anti-viral drugs using micellar liquid chromatography: Application to dosage form analysis

A micellar liquid chromatographic (MLC) method was developed to separate and analyze four anti-viral drugs. The method utilized a Thermo Hypersil ODS C18 HPLC column with an isocratic elution mode employing a mobile phase consisting of sodium dodecyl sulfate (0.15 M, pH 3), isopropanol and triethylamine (79.7:20:0.3, v/v/v). The Design Expert 8® software was used to optimize four factors simultaneously and the developed quadratic D-optimal model could achieve maximum resolution between peaks while minimizing the run time. The method was found linear over the concentration ranges of 10–100 μg/mL for sofosbuvir, daclatasvir, and 20–200 μg/mL for ledipasvir and velpatasvir, and successfully applied to the analysis of sofosbuvir and velpatasvir in tablets. The MLC method was compared with a previously reported high-performance liquid chromatography (HPLC) method using the analytical GREEnness metric approach (AGREE), and was found to exhibit greener performance due to the use of safer reagents. The results indicate the high potential of micellar liquid chromatography in the separation of quaternary mixtures with the aid of response surface methodologies.

Micellar enhanced chromatographic separation of selected hazardous chemical present in hair dye and their detection in formulations and swab, including assessment of damage caused to cuticle of hair shaft

Hydroquinone (HQ), resorcinol (RS), m-aminophenol (m-AMP) and p-phenylenediamine (p-PPD) are aromatic compounds which are generally used in hair dyes to provide different colours to hair. In European Union the concentrations of HQ, RS, m-AMP and p-PPD is regulated in hair dyes and other cosmetic products by EU commission regulation EU/2019/831. This legislation is generally exercised because all these compounds are toxic and may cause severe allergies when used regularly. However in India no such regulations exist to monitor these toxic compounds in hair dyes therefore in this study a simple, rapid, economical and ecofriendly micellar liquid chromatographic (MLC) technique has been developed which can monitor all the selected toxic compounds simultaneously. HQ and RS are positional isomers and are difficult to be separated by HPLC whereas with the developed MLC method it was well separated and detected. The developed MLC technique has been applied to detect and quantify selected analytes in oxidative and non-oxidative hair dyes and swab samples from the scalp. The simultaneous separation of selected analytes was performed in mobile phase 0.09 M SDS, 0.01 M NaH2PO4–2% v/v 1-butanol at pH 7 running through C18 column under isocratic mode at 1 mL/min. flow rate. All the analytes were eluted within 6 min. The present method has been validated following the EURCHEM Guideline, 2014 in terms of calibration range (0.08–15 µg/mL), limit of detection (0.01–0.09 µg/mL), limit of quantification (0.08–0.35 µg/mL), accuracy (<5.6%), precision (91–105%) and robustness (<5.8%). The selected compounds in hair dye formulation were found in the range of 0.06–12.2 µg/mL (when diluted 25 times). Hair dyes persistence study was conducted up to 10 days from the day of application on the scalp, suggesting that the dyes were not completely washed off and were retained on the scalp for more than one week. SEM analysis of dyed hair revealed that hair are severely damaged due to use of dyes. The advantage of the developed method is that it could easily be adopted by quality control and cosmetic laboratories for quality control and check for the simultaneous separation of positional isomers together with two other aromatic compounds.

Eco-friendly micellar HPLC approach for assessment of two anti-asthmatic breezhalers; Application of central composite design

Short-term breathing problems are brought on by asthma, a chronic lung disease. Mometasone furoate (MOF) and Indacaterol (IDT), are co-formulated alone or with Glycopyrronium (GLY) in the form of inhalation powder to control the symptoms of asthma. A novel green hybrid micellar liquid chromatographic method was developed to analyze the three mentioned medications. Contrary to routine analysis, Quality by Design methodology was applied to maximize the resolution with the fewest number of trials. Fractional factorial design was used to study the impact of three significant variables: sodium dodecyl sulphate (SDS) concentration, methanol %, and the mobile phase pH. Separation of the analytes was optimized by central composite design using a mobile phase consists of (191.49 mM) SDS and (10.00 mM) potassium dihydrogen phosphate buffer: methanol (77.50: 22.50 v/v), pH 3.00 on a reversed phase C18 column, within eight minutes. The flow rate was 1.2 mL/min, with 20 µL injection volume, and UV detection at 210 nm. Green Analytical Procedure Index, and Analytical Greenness Calculator were used for the method’s greenness evaluation, and it was deemed to be an effective green methodology. The developed approach was effectively applied for quantitative determination of the three drugs in bulk powder and two pharmaceutical dosage forms. International Conference of Harmonization requirements were adhered to when validating the approach. Under optimized conditions, calibration curves of the studied drugs were linear over the concentration range of (10.00 – 100.00 µg/mL) with high accuracy results and correlation coefficients of 0.9997 for MOF, 0.9996 for IDT and 0.9996 for GLY. Additionally, a precise approach has been demonstrated by the intra- and inter-day coefficients of variation ≤ 2%. The LOD and LOQ were (2.39 μg/mL) and (7.25 μg/mL) for MOF, (2.67 μg/mL) and (8.08 μg/mL) for IDT, and (2.80 μg/mL) and (8.48 μg/mL) for GLY, respectively.

Enhanced fluorimetric detection of diphenylpyraline HCl using micelle and cyclodextrin mediated approach: Spectrofluorimetric and micellar liquid chromatographic application for either single or combined formulation with caffeine and paracetamol

Highly sensitive micellar spectrofluorimetric method (Method I) has been developed and validated for the determination of diphenylpyraline HCl in pharmaceutical tablets and in plasma. Sodium dodecyl sulfate improves the intensity of fluorescence of diphenylpyraline at 286 nm at pH 5 that allow its determination in plasma at nano-level. the mean percent recovery ± S.D was 99.719 ± 0.338 in plasma. In addition, Green cyclodextrin-modified micellar liquid chromatographic method (Method II) has been developed and validated for simultaneous determination of diphenylpyraline, paracetamol and caffeine using cyclodextrin micellar mobile phase consisted of 30 mM Brij*35, 0.5 mM hydroxypropyl β-cyclodextrin and phosphate buffer pH 4: MeOH (95:5, %v/v) that allows their simultaneous determination with enhanced spectrofluorimetric detection of diphenylpyraline. Method II was effectively applied for the simultaneous determination of diphenylpyraline, paracetamol and caffeine in a ternary laboratory prepared mixture which contained all possible excipients with mean percent recoveries ± S.D of 100.176 ± 1.008, 101.166 ± 0.415 and 100.708 ± 1.836, respectively. Linearity range for Method I was 0.1–1 μg. mL−1 for diphenylpyraline and for Method II was 0.3–50, 25–350, and 0.5–50 for caffeine, paracetamol and diphenylpyraline, respectively. Method I was also applied in spiked human plasma with linearity range 0.2–0.5 μg. mL−1. The methods are verified to have excellent greenness.

Multiple sensitive eco‐friendly analytical approaches for the determination of two fourth‐generation fluoroquinolones: Application to stability study and content uniformity testing

Multiple sensitive eco-friendly analytical techniques were applied for the assessment of two important fourth-generation fluoroquinolones namely, gemifloxacin (GFX), and gatifloxacin (GTF). GFX, which is utilized as an essential adjunct therapy for the management of pneumonia in SARS-CoV-2 was determined by green indicating micellar liquid chromatographic in authentic powder and dosage forms. The separation was performed by using a reversed-phase C18 column; the micellar mobile phase comprised of 12.5% n-propanol, 0.15 M sodium lauryl sulfate, and 0.3% triethylamine in 0.02 M O-phosphoric acid adjusted to pH 3.0 and pumped at 1 ml/min flow rate and detected at 266 nm by UV detection. The method was linear over the range of 4.0–90 μg.ml−1 with a recovery percentage of 99.81 ± 0.69. The acidic degradation behavior of GFX along with the kinetic investigation was evaluated as recommended by ICH-stress conditions. The separation of the degradation product was performed in good elution time (less than 8 min), and the suggested technique has a good reproducibility (R.S.D. less than 1.0%) and provides an excellent resolution (Rs = 4.5) between GFX and its degradation product. Concerning the second drug, GTF, simple, extremely sensitive, and accurate spectrofluorimetric and spectrophotometric techniques were adopted for the determination of the drug in its pharmaceutical preparations. The suggested approaches utilize the concept of complex formation with eosin Y in an aqueous buffered solution. Regarding the spectrophotometric method (method I), the binary complex has a maximum absorption at 544 nm, while for spectrofluorimetric determination (method II) the formed complex was recorded at λem 491 nm after excitation at 286 nm. For both approaches, variables affecting the formation of the binary complexes were extensively investigated and optimized. The suggested techniques were shown to be rectilinear across the concentration range of 0.5–8 and 0.05–1 μg.ml−1, respectively, with recovery percentages of 100.34 ± 0.85 and 99.90 ± 0.81 for method (I) and method (II), respectively. In compliance with ICH guidelines, the analytical performance of the suggested techniques was thoroughly validated. Moreover, uniformity testing was also applied successfully for the evaluation of GFX by the proposed micellar liquid chromatographic method. To ensure the proposed methodology's greenness, The AGREE calculator software was adopted and the results obtained revealed an excellent greenness of the proposed approaches.

Application of micellar liquid chromatographic method for rapid screening of ceftriaxone, metronidazole, amoxicillin, amikacin and ciprofloxacin in hospital wastewater from Sagar District, India

• A rapid green chromatograpic method was developed. • Developed Method is suitable for routine analysis of CTX, CPFX, MTZ, AMO and AMK in hospital wastewater. • Separation of the selected antibiotics was accomplished within 11 min. • The method was applied on samples of wastewater from 25 hospitals out of which 13 have found positive. • The minimum reported concentration 0.05 µg/mL while the maximum was 11.7 µg/mL. The present research work mainly highlights the simultaneous detection of five antibiotics i.e., ceftriaxone (CTX), metronidazole (MTZ), amoxicillin (AMX), amikacin (AMK) and ciprofloxacin (CPFX) in hospital wastewater located in Sagar district (Madhya Pradesh, India). All these antibiotics make their way through drainage systems into the environment in the form of metabolized and unmetabolized compounds. Growing concern about the antibiotic resistance and contamination of wastewater by antibiotics requires fast, sensitive and eco-friendly techniques. Therefore a simple, rapid and eco-friendly chromatographic method has been developed for simultaneous determination of CTX, MTZ, AMX, AMK and CPFX in hospital wastewater samples. Optimization of the method was accomplished using response surface methodology (RSM) with Box-Behnken design (BBD). The optimized mobile phase was 0.15 M SDS-0.01 M NaH 2 PO 4 -7% (v/v) 1-butanol, pH 3 which provided a chromatographic run time of 11 min. for the simultaneous determination of selected antibiotics. The correlation coefficient (r 2 ) values were satisfactory between 0.996 and 0.999 over the linear concentration range of 0.04–12 μg/mL. Limits of detection (LODs) and the limits of quantification (LOQs) for the five antibiotics were in the range of 0.02–0.18 μg/mL and 0.04–0.25 μg/mL, respectively. The developed method is simple, rapid, cost-effective and green which could be used for complex matrix (wastewater) without any sample pretreatment other than filtration. The results indicated that the MLC-PDA method proved to be more suitable than reverse phase-high performance liquid chromatography for the simultaneous separation of selected antibiotics.

Rapid simultaneous determination of coumarins and organic acids in notopterygium by an isocratic micellar liquid chromatography based on Box-Behnken design

This work has developed an isocratic micellar liquid chromatographic method for simultaneous determination of nodakenin, isoimperatorin, psoralen, ferulic acid, and chlorogenic acid in notopterygium and notopterygium processed products for the first time. Analytes were successfully separated within 15 min. The optimized chromatographic conditions were obtained by Box-Behnken design optimization, and the mobile phase consisted of 0.064 M sodium lauryl sulfate aqueous solution and 8.15% n-pentanol with a pH value of 3.04. The analytes were eluted isocratically through a C18 column at a flow rate of 1 mL/min. The linear ranges, limit of detection, limit of quantitation, recovery, intra-day and inter-day precision of the proposed method were validated according to ICH guidelines. The proposed method was successfully applied to the quantitative the 5 active components in notopterygium and its processed products. It is a simple, efficient, and low-cost analytical method that provides an alternative method for the determination of the 5 active ingredients in notopterygium.

Direct injection green chromatographic method for simultaneous quantification of amoxicillin and amikacin in maternity hospital wastewater (Sagar, India)

Amoxicillin (AMO) and amikacin (AMK) are broad-spectrum antibiotics that are most preferably given post-delivery (normal and cesarian) in the maternity hospitals located in Sagar city (Madhya Pradesh), India. Both the antibiotics make their way through sewage/drainage systems into the environment in the form of metabolized and unmetabolized compounds. Growing concern about the contamination of wastewater by antibiotics requires fast, sensitive and eco-friendly techniques. Therefore a simple, rapid and environmental friendly chromatographic method has been developed for simultaneous determination of AMO and AMK in maternity hospital wastewater samples. A micellar liquid chromatographic (MLC) method was developed with a C18 column (250 mm × 4.6 mm), sodium dodecyl sulphate (SDS; 0.15 M), 1-butanol (7%) as a modifier, pH 5 and photo diode detector (PDA) at 270 nm and 256 nm for AMO and AMK respectively. The method was fast with analysis time below 9 min. In the present MLC method, linearities (r > 0.998), limits of quantification in the range of 0.02–0.04 μg/mL, repeatabilities, and intermediate precision below 4.9% were adequate for the quantification of AMO and AMK. The proposed method can be utilized to detect and quantify both the antibiotics in various samples by hospitals, pharmaceutical companies, pollution control board, municipal corporations, etc.

Evaluating micellar liquid chromatographic methods on octadecyl particle-based and monolithic columns to predict the skin permeation of drug and cosmetic molecules

A micellar liquid chromatographic method was developed to assist in the modeling of the skin permeability of pharmaceutical and cosmetic compounds. The composition of the mobile phase was determined by means of a two-factor central composite design, after which it was tested on both a particle-based and monolithic column. The latter provided the opportunity to increase the flow rate from 1 to 8 mL/min without reaching too high backpressures. The micellar conditions allowed analyzing a large test set of compounds with diverse characteristics with just one mobile-phase composition. The obtained experimental chromatographic descriptors besides two sets of theoretical molecular descriptors were used to model the skin permeability coefficient log Kp, applying multiple linear regression and partial least squares regression approaches. The micellar method on the monolithic column provided useful models with similar or even slightly better performance parameters than the method on the particle-based column. Furthermore, a much faster analysis can be achieved when applying a flow rate of 8 mL/min, making the micellar monolithic method ideal to estimate skin permeability.

Applying eco‐friendly micellar liquid chromatography for the simultaneous determination of two ternary mixtures utilized for cold treatment using monolithic column

AbstractRapid, isocratic, and sensitive micellar liquid chromatographic methods were developed successfully for the analysis of two ternary mixtures: phenylephrine hydrochloride (PHE), ibuprofen (IBU) and chlorpheniramine maleate (CP) (mixture I), and pseudoephedrine hydrochloride (PSE), IBU and CP (mixture II) in their synthetic mixtures and pharmaceutical dosage forms. Analytical separation was achieved in 7 min using monolithic column adopting UV detector at 233 and 218 nm for mixture I and II, respectively. For both mixtures, a micellar mobile phase solution composed of 0.15 M sodium dodecyl sulphate, 15% n‐propanol, and 0.3% triethylamine adjusted to pH 4.0 by 0.02 M phosphoric acid was utilized applying a flow rate of 1.2 ml/min. The methods were fully validated in accordance with the International Conference on Harmonization guidelines. The proposed methods were linear in the range of 0.5–20.0 μg/ml for PHE and 10.0–400.0 μg/ml for IBU, and CP 0.25–8.0 μg/ml (mixture I) and in the range of 3.0–60.0 μg/ml for PSE and 20.0–400.0 μg/ml for IBU, and CP 0.2–4.0 μg/ml (mixture II) and methanol was utilized as diluting solvent. Furthermore, the proposed methods exhibited good accuracy and repeatability (R.S.D. &lt; 2.0%). The limits of detection were 0.07 (PHE), 1.85 (IBU), 0.04 (CP) for mixture I and were 0.41 (PSE), 2.37 (IBU), 0.02 (CP) for mixture II. The limits of quantitation were 0.22 (PHE), 5.61 (IBU), 0.12 (CP) for mixture I and were 1.24 (PSE), 7.17 (IBU), 0.07 (CP) for mixture II, respectively. The new chromatographic method could successfully substitute traditional hazardous liquid chromatographic methods for the separation of the provided polar compounds consuming lower percent of environmentally toxic organic solvents.

Enantioseparation of racemic amino alcohols using green micellar liquid chromatography and confirmation of absolute configuration with elution order

ABSTRACT Micellar liquid chromatographic method was developed for the enantioseparation of racemic amino alcohols. For that, diastereomeric derivatives of amino alcohols were prepared with activated ester of (S)-ketoprofen and separated on C18 column of RP-HPLC using the aqueous solution of surfactant (Brij-35 and SDS) as an alternative of the organic solvents. Also, chromatographic conditions were optimized by varying concentration of surfactant in aqueous solution, and by varying concentration and pH of the buffer. In addition, density functional theoretical calculations (DFT), validation [LOD (0.245 ng mL−1) and LOQ (0.735 ng mL−1)] and green-assessment score (82 score) were calculated for the developed method.

Micellar liquid chromatographic green enantioseparation of racemic amino alcohols and determination of elution order.

A micellar liquid chromatographic method was developed for the green enantioseparation of racemic amino alcohols using an aqueous solution of the mixed surfactants as an alternative for organic solvents. In this study, the derivatives of the amino alcohols were synthesized using highly reactive chiral esters of (S)-levofloxacin (Lfx) under microwave conditions, and an aqueous solution of the surfactants (Brij-35 and SDS) was used for the enantioseparation of the synthesized diastereomeric derivatives (DDs) of amino alcohols using reversed-phase HPLC. The activated ester of Lfx was synthesized by reacting with N-hydroxybenzotriazole and characterized using UV, IR, 1 H NMR, high-resolution mass spectrometry, and elemental analysis. The DDs of racemic amino alcohols were separated on a C18 column using micellar LC. Chromatographic conditions were optimized by varying the concentration of the surfactants in aqueous solution and by varying the concentration and pH of the buffer. The green assessment score was calculated for the developed method (score: 82, an excellent green method). In addition, the density functional theory calculations were performed to develop the lowest energy-optimized structures of DDs. The method was validated according to the International Conference of Harmonization guidelines, and the retention factor (k), selectivity factor (α), resolution factor (RS ), limit of detection (0.198 ng mL-1 or 0.291 pM mL-1 ), and limit of quantification (0.594 ng mL-1 or 0.873 pM mL-1 ) were calculated.

A sensitive micellar liquid chromatographic method for the rectification of enantiomers of esmolol, and determination of absolute configuration and elution order

A green chromatographic method is proposed for the enantioseparation of Esmolol (Amino alcohol) in which aqueous solution of the mixed surfactants is used as the alternative of organic solvents. In this work, the diastereomeric derivatives of racemic esmolol were prepared, under microwave heating conditions, using highly reactive activated chiral esters of the (S)-levofloxacin, (S)-ketoprofen, and (S)-ibuprofen. The prepared diastereomeric derivatives were separated using surfactant based mobile phase on RP-HPLC. The effect of the varying concentration of surfactant (Brij-35 and SDS) in the eluting phase was investigated for separation and elution of synthesized diastereomeric derivatives. The green assessment score was calculated (obtain score points were 82) for developed method. In addition, the density functional theory calculations were performed, using Gaussian 09 rev. A.02 and hybrid density functional B3LYP with 6-31 G* basis set program, in order to develop lowest energy optimized structures of diastereomeric derivatives. The optimized structures used to predict elution order of synthesized diastereomeric derivatives. Our method was characterized by the following validation parameter: LOD (0.289 ng mL−1), LOQ (0.867 ng mL−1), calibration range (0.006–6.0 mg mL−1), correlation coefficient (0.999) and recovery (99.97 and 99.85% for intra-day assay and 99.42 and 99.75% for inter-day assay).

Simultaneous analysis of blasticidin S and kasugamycin with micellar liquid chromatography

A simple and fast micellar liquid chromatographic (MLC) method for simultaneous analysis of the antibiotic fungicides of blasticidin S and kasugamycin was developed. Chromatographic separation was achieved on a Phenomenex® Aqua 5μ C 18 125 A column. The mobile phase consisted of an aqueous mixture of 69.3 mM sodium dodecyl sulfate (SDS) with deionized water (50 : 1, v/w). The flow rate was set at 1.0 mL/min, and the absorbance was monitored at 210 nm with a photodiode array detector. The total run time was less than 10 min, and the retention times (t r) were 2.47 min for blasticidin S ion, and 7.15 min for kasugamycin ion. Good linear relationships were obtained with correlation of coefficients (r) of 0.997 for kasugamycin, and 0.999 for blasticidin S. The limits of detection (LODs) of blasticidin S and kasugamycin were 0.5 μg/mL and 0.75 μg/mL, respectively, and the limits of quantitation (LOQs) for blasticidin S and kasugamycin were 1.5 μg/mL and 2.2 μg/mL, respectively. The recoveries of blasticidin S and kasugamycin in blank irrigation water ranged from 94.9-97.3% and 87.8-99.7%, respectively. By using MLC method blasticidin S and kasugamycin could be analyzed simultaneously.

An efficient method for the determination of enantiomeric purity of racemic amino acids using micellar chromatography, a green approach.

A simple, sensitive and green micellar liquid chromatographic method (RP-HPLC) was developed for enantioseparation of four racemic amino acids, namely, (RS)-selenomethionine, (RS)-methionine, (RS)-cysteine and (RS)-penicillamine. An aqueous solution of sodium dodecyl sulfate and Brij-35 was prepared and used as mobile phase for HPLC analysis. Activated esters of (S)-ibuprofen, (S)-ketoprofen and (S)-levofloxacin were synthesized by reacting them with N-hydroxybenzotriazole. These esters were characterized by UV, IR, 1 HNMR, HRMS and elemental analysis. These chiral reagents (activated esters) were used for the synthesis of diastereomeric derivatives of the chosen amino acids. The diastereomeric derivatives were separated on a C18 column by micellar liquid chromatography. Chromatographic conditions were optimized by varying concentration of surfactant in aqueous solution, and by varying the concentration and pH of the buffer. The green assessment score was calculated for the developed method (78, an excellent green method score). In addition, density functional theory calculations were performed, using Gaussian 09 rev. A.02 and hybrid density functional B3LYP with a 6-31G* basis set program, in order to develop lowest energy optimized structures of diastereomeric derivatives. The method was validated according to International Conference on Harmonization guidelines and the retention factor (k), selectivity factor (α), resolution factor (RS ) and limit of detection (0.295 ng ml-1 ) and limit of quantification (0.896 ng ml-1 ) were calculated.

Quantification of rifampicin and rifabutin in plasma of tuberculosis patients by micellar liquid chromatography

A Micellar Liquid Chromatographic method is described to determine Rifampicin and Rifabutin in plasma from Tuberculosis patients. Samples were diluted in mobile phase and then directly injected, avoiding long and tedious extraction steps. The analytes were resolved from the matrix without interferences from endogenous compounds using a mobile phase of sodium dodecyl sulfate 0.15 mol L-1–6%(v/v) 1-pentanol and phosphate buffer at pH 3, running at 1 mL min−1 through a C18 column at 25 °C. Detection was carried out by UV absorbance at 270 nm. Under these conditions, the final chromatographic analysis time was 22 min. The analytical methodology was validated following the FDA 2018 Bioanalytical Method Validation Guidance for Industry. The response of the drugs in plasma was linear in the 0.05–5 μg/mL range, with r2 > 0.9993. Trueness and precision were <14% for both substances. Carry over and matrix effects were negligible. Dilution integrity, robustness and stability were also investigated. Method was reliable, economic, eco-friendly, safe, easy-to-conduct, and with a high sample throughput, thus useful for routine analysis. Finally, the analytical method was used to determine both antituberculosis drugs in incurred plasma samples of Tuberculosis patients.